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Principal Fundamentals of Residential Construction, Third edition
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JWBT418-FM.indd i 1/25/11 5:21 PM Fundamentals of Residential Construction JWBT418-FM.indd i 2/16/11 5:02 PM JWBT418-FM.indd ii 2/16/11 5:02 PM FUNDAMENTALS OF RESIDENTIAL CONSTRUCTION THIRD EDITION E dw a rd Allen and Rob T ha llon Featuring the Drawings of Joseph Iano John Wiley & Sons, Inc. JWBT418-FM.indd iii 2/16/11 5:02 PM This book is printed on acid-free paper. o Copyright © 2011 by John Wiley & Sons. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201)748-6008, or online at http:// www.wiley.com/go/permission. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional person should be sought. The drawings, tables, descriptions, and photographs in this book have been obtained from many sources, including trade associations, suppliers of building materials, governmental organizations, and architectural firms. They are presented in good faith, but the author, illustrator, and Publisher do not warrant, and assume no liability; for, their accuracy, completeness, or fitness for any particular purpose. It is the responsibility of users to apply their professional knowledge in the use of information contained in this book, to consult the original sources for additional information when appropriate, and to seek expert advice when appropriate. The fact that an organization or web site is referred to in this work as a citation and/ or a potential source of further information does not mean that the author or the Publisher endorses the information that the organization or web site may provide or recommendations it may make. Further, readers should be aware that Internet web sites listed in this work may have changed or disappeared between the time the work was written and the time it was read. For general information about our other products and services, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. For more information about Wiley products, visit our web site at www.wiley.com. Library of Congress Cataloging-in-Publication Data: Allen, Edward, 1938Fundamentals of residential construction / Edward Allen and Rob Thallon; featuring the drawings of Joseph Iano. – 3rd ed. p. cm. Includes index. ISBN 978-0-470-54083-1 (hardback) ISBN 978-0-470-90510-4 (ebk); ISBN 978-0-470-90511-1 (ebk); ISBN 978-0-470-90512-8 (ebk); ISBN 978-0-470-95091-3 (ebk); ISBN 978-0-470-95108-8 (ebk) 1. House construction. I. Thallon, Rob. II. Iano, Joseph. III. Title. TH4811.A463 2011 690'.837–dc22 2010050395 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 JWBT418-FM.indd iv 2/16/11 5:02 PM C onte nt s 2 The Construction Community: Builders, Contractors, and Developers 30 History 32 Builders and Contractors 33 Obtaining Work 38 The Residential Developer 40 Training the Construction Community 45 Green Builders, Contractors, and Developers 47 3 Preface xi Acknowledgments xi PART ONE CONTEXT 1 1 The Context for Construction 2 A Building Culture 7 Construction Systems 9 Types of Residential Development 11 Zoning Ordinances, Building Codes, and Other Legal Constraints 17 Building Costs and Financing 18 Environmental Responsibility: Building Green 21 Building a House: The Typical Process 23 The Design Community 50 History 52 Residential Designers 53 Consultants 55 The Design Process 56 Design Sources 63 Communication between Designer and Builder 65 Green Designers 68 PART TWO MATERIALS 4 71 The Material Wood Trees 74 Lumber 78 Wood Products 88 Chemical Treatment 72 99 v JWBT418-FM.indd v 2/16/11 5:02 PM vi / Contents PART THREE WOOD LIGHT FRAME CONSTRUCTION 169 7 Rough Sitework 170 Design Considerations 172 Organizing the Site for Construction 173 Site Preparation 173 Excavation 175 Site Utilities 176 Surface Water Drainage 181 Grading 184 Green Practices for Rough Sitework 186 Wood Fasteners 100 Wood-Manufactured Building Components 106 Types of Wood Construction 106 Building Green with Wood 106 5 Masonry 110 History 112 Mortar 115 Concrete Masonry 116 Brick Masonry 126 Stone Masonry 138 Other Types of Masonry Units 142 Special Problems of Masonry Construction 143 Building Green with Masonry 145 6 Concrete 148 History 150 Cement and Concrete 151 Making and Placing Concrete 154 Formwork 158 Reinforcing 158 ACI 301 165 Building Green with Concrete 165 JWBT418-FM.indd vi 8 Foundations 190 Foundation Loads 192 Foundation Settlement 192 Soils 193 Designing Foundations 195 Footings 198 Concrete Foundation Walls 201 Concrete Masonry Foundation Walls 204 Concrete Slab Foundations 206 Wood Foundations 210 Precast Concrete Foundations 212 Anchor Bolts and Hold-downs 212 Drainage and Waterproofing 212 Foundation Insulation 215 Backfilling 216 Foundation Design and the Building Codes 216 9 Floor and Wall Framing 218 History 220 The Platform Frame 220 Building the Frame 222 2/16/11 5:02 PM / vii Contents 10 Roof Framing 248 14 History 250 Roof Types and Parts 251 Building the Roof 253 Wood Framing and the Building Codes 271 The Uniqueness of Wood Light Frame Construction 272 Building Green with Wood Framing 274 11 Finishing the Roof 276 Preparation for Roofing 278 Roof Slope 280 Steep Roofs 281 Low-Slope Roofs 293 Roof Edge Details 298 Roof Drainage 301 Roofing and the Building Codes 303 Building Green with Roofing 304 12 Windows and Exterior Doors 306 Plumbing 352 Plumbing Basics 354 Planning for Pipes 358 Rough-in Plumbing 359 Finish Plumbing 362 Plumbing Codes 362 Other Piping Systems 363 Building Green with Plumbing Systems 366 15 Heating and Cooling 370 Choosing a System 372 Forced-Air Systems 374 Radiant Panel Systems 380 Hydronic Heating Systems 384 Local Source Heaters 385 Finishing a Heating/Cooling System 388 Heating and Cooling Systems and the Building Codes 388 Green Strategies for Heating and Cooling Buildings 388 Windows 308 Exterior Doors 320 Building Green with Windows and Doors 325 13 Finishing the Exterior Walls 328 The Weather Barrier Membrane 331 Exterior Trim 333 Siding 334 Exterior Paints and Coatings 344 Ladders and Scaffolds 348 Building Green at the Exterior Walls 350 JWBT418-FM.indd vii 2/16/11 5:02 PM viii / Contents 18 Fireplaces and Stoves 434 Selecting a Fireplace 437 Planning for Fireplace Construction 438 The Masonry Fireplace 438 Factory-Built Fireplaces 448 Freestanding Stoves 451 Fireplaces and the Building Codes 452 How Green Are Fireplaces and Stoves? 454 19 Interior Surfaces 456 Wall and Ceiling Finish 458 Finish Flooring 465 Building Green with Gypsum Products 472 16 Electrical Wiring 392 Wiring Basics 394 Electrical System Design 400 Rough-in Electrical Installation 402 Finish Electrical 404 Electrical Wiring and the Building Codes 405 Low-Voltage Wiring 405 Building Green with Electrical Systems 406 17 Thermal Insulation 408 The Thermal Envelope and Its Components 411 Thermal Insulation Materials 415 How Much Insulation? 420 Installation of Insulation 420 Control of Water Vapor 422 Ventilation of Cavities 424 Control of Air Infiltration 428 Building Green with Thermal Insulation 430 JWBT418-FM.indd viii 20 Finishing the Interior 474 Interior Doors 476 Cabinets 479 Finish Carpentry and Trim 486 Paints and Coatings 493 Building Green with Paints and Coatings 494 21 Finish Sitework 496 Paving Systems 498 Level Changes 501 Porches and Decks 505 Finish Grading 506 Fencing 507 Outdoor Lighting 509 Irrigation 510 Planting 511 Green Considerations in Finish Sitework 512 2/16/11 5:02 PM Contents PART FOUR ALTERNATIVE CONSTRUCTION SYSTEMS 22 25 Multifamily Construction 516 Low-Tech, Low-Energy Construction 546 Earthen Construction 548 Stacked Log Construction 556 Straw Bale Construction 562 The "Greenness" of Earth, Logs, and Bales 571 24 Timber Frame Construction 592 515 History 518 Special Issues 521 Foundations 521 Framing 530 Acoustical Separation 533 Fire Protection 533 Systems 536 Accessibility 539 Site Management 540 Green Issues for Multifamily Housing 541 23 / ix The Uniqueness of the Timber Frame 595 Materials and Structure of the Timber Frame 596 Building a Timber Frame House 600 Timber Framing and the Building Codes 606 Building Green with Heavy Timber 606 26 Light-Gauge Steel Construction 608 Light-Gauge Steel Frame Construction 610 Building Green with Steel Framing 620 27 Panelized Construction 622 The Concept of Panelized Construction Types of Panels 625 Framed Panel Systems 626 Structural Insulated Panels 630 Glossary Loadbearing Masonry and Concrete Construction 574 Index 624 643 669 Loadbearing Masonry 576 Insulating Concrete Forms 582 JWBT418-FM.indd ix 2/16/11 5:02 PM JWBT418-FM.indd x 2/16/11 5:02 PM P refac e When Fundamentals of Building Construction, Materials and Methods, was first published more than 25 years ago, it filled a void and quickly was adopted by hundreds of colleges and universities as a text for general courses in construction technology. It also precipitated immediately the first of a growing stream of requests from teachers for a companion volume that would concentrate on residential construction while retaining the qualities of the parent book. We were pleased to respond to those requests with Fundamentals of Residential Construction, which was first published in 2002. The book that you hold in your hands is the third edition of that volume, and it contains numerous improvements. This third edition inherits several important traits from its predecessors: It is straightforward and readable, and it contains extensive drawings and photographs. These elements are blended on attractive pages, and, for the reader's convenience, each illustration appears on the same two-page spread as its referencing text. Retained, too, is the concern for both technical and aesthetic matters, because we believe that they are important for the quality of buildings and the lives of the people who inhabit them. New to this edition are a chapter on multifamily construction and an expanded discussion of green building practices. In addition, the entire text has been edited to include updated and emerging building practices and to improve readability. Over 80 new photographs and illustrations have been added, and the glossary of building terms has been expanded significantly. Although both of us teach in schools of architecture, we are not mere ivory-tower academicians. Between us, we are the architects of well over 200 constructed houses and innumerable remodeling projects. Both of us have spent countless hours on construction sites, working with residential builders, developers, contractors, and craftspeople on the day-to-day minutiae of getting houses built. We have both constructed houses with our own hands, from excavation to finishes. In addition, both of us have authored books on construction that have found enthusiastic acceptance in the building professions. To make this book inclusive of regional differences in construction practices, we have found that it has been extremely helpful that one of us works in wintry New England and the other in the damp but mild Pacific Northwest. To extend the boundaries of our own experiences, we also have consulted frequently with colleagues in other regions of the United States and Canada. xi JWBT418-FM.indd xi 2/16/11 5:02 PM JWBT418-FM.indd xii 2/16/11 5:02 PM Ac knowl edgm ents Edward Allen is grateful to be teamed with Rob Thallon, a gifted teacher, accomplished author, and awardwinning architect of some of the loveliest, most livable houses ever constructed. He offers apologies to Dee Etzwiler and Carter and Claire Thallon for involving their husband and father, respectively, in an enterprise that kept him holed up in his office for many hours over a period of several years. He thanks Rob for sharing his vision of excellence and making this book so special. He is grateful to Joseph Iano, whose ideas and innovations for the parent book still shine in this book. And he thanks Mary M. Allen for her support and encouragement. Rob Thallon is especially thankful to Edward Allen, his mentor and friend, for selecting him to work on this important project. He also thanks his coauthor for having been his keenest critic and most fervent champion during his previous writing projects, and he notes that their collaboration on this book has deepened his appreciation for the clarity of Edward Allen's vision and his language. He wishes to thank the talented illustrators Mu-Yun Chang, Lisa Ferretto, Laura Houston, and Dave Bloom, who helped develop and render drawings for the original edition; and Ben Rippe and John Arnold, who contributed illustrations and organizational brilliance to the second edition. Finally, thanks and a deep appreciation to Jesse Crupper, Dee Etzwiler, and Hank Warneck, whose research, photography, and illustrations were instrumental to the quality of this third edition. Together, Edward Allen and Rob Thallon are both grateful to all the people at John Wiley & Sons, Inc., who have given so much of themselves in producing this book. We thank especially Publisher Amanda Miller, Editor Paul Drougas, Developmental Editor Lauren Olesky, and Senior Production Editor Donna Conte. Like the quality of a house, the quality of a book is proportional to the skill and dedication of the individuals on the production team. Edward Allen South Natick, Massachusetts Rob Thallon Eugene, Oregon xiii JWBT418-FM.indd xiii 2/16/11 5:02 PM JWBT418-FM.indd xiv 2/16/11 5:02 PM PART ONE Context JWBT418-01.indd 1 1/25/11 3:10 PM JWBT418-01.indd 2 1/25/11 3:10 PM 1 The C onte xt f or C onstr uc tion • A Building Culture Contractors and Subcontractors Builders and Developers Designers Material Manufacturers and Distributors Realtors Regulatory Agencies Financial Institutions Educational and Research Institutions Associations Publishers • Construction Systems • Types of Residential Development • Zoning Ordinances, Building Codes, and Other Legal Constraints Zoning Ordinances Building Codes Other Legal Constraints • Building Costs and Financing Building Costs Financing • Environmental Responsibility: Building Green Energy Efficiency Resource Efficiency Low Toxicity • Building a House: The Typical Process Building Permits and Inspections Building Site Preparation The Foundation Structural Framing Roofing and Siding Utilities and Insulation Interior and Exterior Finish 3 JWBT418-01.indd 3 1/25/11 3:10 PM People have been building houses for thousands of years. These houses have provided shelter, afforded privacy, defined territory, enhanced status, and, in some cases, provided defense. The earliest houses were opportunistic uses of naturally sheltered places like caves and were more like nests than houses. As time passed, people learned to assemble materials collected from nature to make simple freestanding structures. In many cultures, these structures evolved into highly crafted houses that are elegant expressions of cultural patterns and values (Figures 1.1 and 1.2). In the past 150 years, technology has afforded us conveniences such as electricity, plumbing, and automatic heating and air conditioning that have made houses, in the words of the famous architect Le Corbusier, "machines for living." Most recently, housing in the industrialized world has emphasized energy conservation and efficient production. Today, residential designers have a rich history from which to draw, and residential builders have the best tools and most complete palette of quality materials with which to build that have ever existed. The challenge for this new generation of designers and builders is to improve the built environment in the face of decreasing natural resources and increasing population. Throughout history, the forms of houses have differed from region to region. House form varies primarily in relation to climate, to available building materials and tools, and to the culture of the people being housed. The influence of climate on house form is dramatically demonstrated by the comparison of the igloo in polar regions with the open-sided palm-thatched structure in tropical zones. The forms of houses in the same climate can vary also, however, because of the use of different building materials. In Mexico, for example, the introduction of reinforced concrete has spawned a collection of flat-roofed houses that contrast sharply with the traditional sloped roof made of timber covered with clay tiles. The culture of the people being housed also has considerable influence on house form. Native American tribes who were nomadic built dwellings such as tepees that were easily folded and transported, while rooted tribes from the same region built stationary houses of earth, stone, and wood. The modern North American house has evolved largely from 16th-century timber-framed houses that had been developed in response to the climate, materials, and culture of northern Europe (Figure 1.3). Early pioneers landing on the eastern shores of North America found a new homeland rich with timber that had to be cleared to make way for development, so it was logical to use wood for the construction of new houses. The settlers soon discovered, however, that the European tradition of exposed timber frame was inadequate in the harsher climate of the New World, so they developed an exterior skin of clapboards to protect the frame (Figure 1.4). This wooden structure and its details evolved over the years in response to changes in tools, transportation, and social norms. Other building materials and systems such as brick and stone masonry developed simultaneously, but were never as prevalent in North America as the clapboard-clad timber-framed building. Then, in the 1840s, after more than 300 years of development, the heavy timber frame yielded its preeminence almost overnight to a new system of construction, the wood light frame. The emergence of the light frame was made possible by two technological developments: mass production of the inexpensive wire nail and the ability of water-powered sawmills to cut large quantities of consistently dimensioned lumber. These developments allowed the large timbers and complicated connections of the traditional timber-framed buildings to be replaced with numerous small structural pieces, simply connected (Figure 1.5). The advantages of the wood light frame over its predecessor were so numerous and compelling that it has dominated residential and other small-scale construction for the 150 years since its introduction, and it still shows no sign of giving way to other systems. Today, the wood light frame accounts for over 90 percent of all new site-built residential construction and is the basis for most factory-built housing as well. 4 JWBT418-01.indd 4 1/25/11 3:10 PM Chapter 1 • The Context for Construction / 5 Figure 1.1 The Roman domus, developed more than 2000 years ago, had individual rooms for common daily functions and was built around a central courtyard that helped to cool the rooms naturally. (From Peter Hodge, The Roman House: Aspects of Roman Life, Longman Group, Ltd., London, 1975) Figure 1.2 A traditional Japanese house from the Nara period, AD 710–784. The house had both open and closed spaces, and the enclosed indoor space had no permanent partitions. Houses such as this have influenced traditional Japanese house design and construction to the present day. (From Nishi Kazuo and Hozumi Kazuo, What Is Japanese Architecture? Kodanshu International, Ltd., Tokyo, 1985) JWBT418-01.indd 5 1/25/11 3:10 PM 6 / Part One • Context Figure 1.3 European timber house forms generally followed a progression of development from crude pit dwellings, made of earth and tree trunks, to cruck frames to braced frames. Figure 1.4 The North American climate was more severe than the European climate, so early pioneers found a way to wrap the wooden frame with cladding, protecting it more securely from the weather than the exposed halftimbers of European houses. This example, built in Essex County, Massachusetts, is still standing. (Photo courtesy Library of Congress, Prints and Photographs Division, Historic American Buildings Survey, Reproduction Number, HABS, MASS, 5-TOP, 1-6) Figure 1.5 The wood light frame uses less material and less labor to construct than does its predecessor, the timber frame. For lateral stability, light framing relies on sheathing such as plywood applied to the exterior of the frame. JWBT418-01.indd 6 1/25/11 3:10 PM Chapter 1 • The Context for Construction A Building Culture Builders and Developers Houses are built within the context of the many individuals and institutions that affect their design and construction. In primitive and vernacular societies, the context is relatively local and involves few people. The head of a household might acquire a piece of land through the family, formulate a simple design based on local traditions, consult with a local builder about schedule and cost, arrange for the purchase of local building materials, and work together with the builder using traditional methods to build the house. The building of a house today in North America involves a much more complex process and many more participants. Nonetheless, all these participants are instrumental to the success of the project, and all are connected to what can be called a residential building culture—a network of people and institutions, which we will call "subcultures," that are directly or indirectly dedicated to the production of houses. The principal subcultures are discussed in the following paragraphs and in later chapters of this book. Builders bring together and coordinate the numerous parts of an entire building project for the purpose of offering it for sale or rent. The builder purchases a building lot, obtains financing, hires the designers and other consultants to produce plans, hires the contractor to do the construction, markets the project, and sells or rents it. Builders can work on one house at a time or can build large tracts of houses or large multifamily structures. Contractors and Subcontractors / 7 Whereas builders are the entrepreneurs who produce houses for sale, developers are entrepreneurs who produce building lots. Developers purchase large tracts of land, contract for the design of roads and utilities, obtain the necessary governmental permissions to develop the land, contract for the installation of roads and utilities, and sell the divided land as building lots. Developers often expand their operation to become builder/developers, and builders likewise can expand in the other direction. Nonprofit builder/ developers produce affordable housing Figure 1.6 The North American wood light frame building system is now used extensively in Japan, where its resistance to earthquakes makes it most practical. (Photo by Rob Thallon) Figure 1.7 Large retail outlets such as this provide one-stop shopping for professional builders and homeowners alike. Because of the large volume of building materials, tools, and books sold at these outlets, prices are usually competitive, and building professionals receive an additional discount. (Photo by Rob Thallon) At the center of today's residential building culture are the contractors and subcontractors whose job it is to construct houses. These people— carpenters, plumbers, masons, electricians, and myriad others—devote their professional lives to assembling materials in concert with one another to make houses. Their work depends on direct contributions from many other sectors of the building culture such as designers, material suppliers, and code enforcement agencies. Indirect contributions from realtors, financial institutions, educators, and publishers also play an important role in their work. Contractors and subcontractors are discussed extensively in Chapter 2. JWBT418-01.indd 7 1/25/11 3:10 PM 8 / Part One • Context for rent or sale to low-income families or individuals. Builders and developers are discussed further in Chapter 2. Designers The members of the building culture most responsible for communication are the designers. This group includes architects, building designers, engineers of several kinds, landscape architects, landscape designers, and interior designers. They are responsible for being knowledgeable about current building practices, understanding and interpreting the various codes and laws that regulate building design, having a current understanding of the availability and performance of building materials, and integrating all these factors into designs that are appreciated by their clients. These various participants in the role of residential design are discussed further in Chapter 3. Material Manufacturers and Distributors There are thousands of companies, large and small, that manufacture and sell the materials and assemblies used to construct houses. The manufacturers generally sell their goods wholesale to retail stores, which, in turn, sell to contractors and to the general public. Contractors, because they are frequent customers who often buy in volume, usually are offered a discount at the retail outlets. Product information in both printed and electronic form is distributed to contractors and designers and is disseminated to the general public via commercial advertising in periodicals. Building material manufacturers have also formed a large number of organizations that work toward the development of technical standards and the dissemination of information with relation to their respective products. The Western Wood Products Association (WWPA), for example, is made up of producers of lumber and wood products. It carries out JWBT418-01.indd 8 Figure 1.8 Lumberyards play an important role in residential construction. Based on a set of building plans, an employee of the yard will estimate the quantity of lumber that is required to build a project and will furnish a competitive bid for the entire package of lumber, delivered to the building site. Yards prefer doing business with contractors who organize their work so that deliveries can be concentrated into five or six truckloads for an average-sized house. (Photo by Rob Thallon) programs of research on wood products, establishes uniform standards of product quality, certifies mills and products that conform to its standards, and publishes authoritative technical literature concerning the use of lumber and related products. Associations with a similar range of activities exist for virtually every material and product used in building. All of them publish technical data relating to their fields of interest, and many of these publications are indispensable references for the architect or engineer. A considerable number are incorporated by reference into various building codes and standards. Realtors Realtors are the salespeople of the building culture and play a critical role in marketing houses built for sale. They are responsible for knowing what the buying public wants in a house and for selling or renting houses as they are built. Because realtors have direct contact with consumers and are in a position to learn their desires, they are frequently queried by resourceful builders who are trying to discover new design features that will make their houses more marketable. New speculative houses are typically advertised and sold by realtors via a listing agreement under which realtors assume numerous responsibilities, including negotiating the price of the house, the terms of the sale, and the conditions of the contract, with particular attention paid to the aspect of financing. For this service, realtors are generally paid a percentage of the cost of each house sold. Large builder/ developers will often create their own real estate company for the purpose of marketing and selling their own houses. Regulatory Agencies Building design and construction are regulated by zoning ordinances and 1/25/11 3:10 PM Chapter 1 • The Context for Construction building codes written for the purpose of providing safe and healthy built environments. Zoning ordinances are local laws that divide the locality into zones and regulate such things as what kinds of buildings may be built in each zone and to what uses these buildings may be put. For example, these regulations restrict the use of buildings within residential zones so that dangerous or obnoxious activities do not get mixed in with houses. Within residential zones, the minimum size of lots, the distance a house must be from the property line, requirements for off-street parking, and maximum fence heights are typically regulated. Building codes are designed to ensure structural safety and a healthy living environment within the house itself. The sizes of structural members, minimum standards for plumbing and wiring, minimum ceiling heights, the design of stairs and handrails, and provision for emergency escape are all examples of the regulations found in the building codes. Zoning ordinances and building codes are further discussed later in this chapter. Financial Institutions Most residential construction projects require financial resources beyond the immediate means of the owner. Banks and other financial institutions provide capital for the projects in the form of long-term loans to qualified owners. The ability to resell a house if the owner defaults on payments is a primary concern of lending institutions, so they are less inclined to loan money for the purchase of houses that appear to be very different from the norm. Financial institutions are further discussed later in this chapter. Educational and Research Institutions Most designers and builders have some formal training. Architects are required to have at least a 5-year professional degree, and most plan service drafters have taken courses in JWBT418-01.indd 9 / 9 drafting and residential construction. Many courses in both the business and the physical skills required of their specialties are offered to contractors and subcontractors. Some contractors and subcontractors are required to be licensed, and there are sanctioned courses offered by different institutions for this purpose. The training of residential designers is explored in Chapter 3, and that of builders and contractors is discussed in Chapter 2. Associations There are many associations that relate to the design and construction of houses. The American Institute of Architects (AIA) and the National Association of Home Builders (NAHB) are two of the largest such associations, and there are numerous other organizations of manufacturers, building trades, and other groups within the building culture. Hybrid groups that include members from several disciplines also exist. For example, the International Code Council (ICC), which is responsible for writing building codes, includes architects, builders, and building code officials. Publishers The publishing industry has long been an integral part of the residential building culture. For hundreds of years, periodicals have advertised the latest building materials, tools, and other products (Figure 1.9). Popular magazines such as Better Homes and Gardens, Sunset, and Home have carried articles about design, while others such as Builder and Fine Homebuilding have focused on construction. Books and journals are devoted to a variety of related topics. Recently, there has been a proliferation of how-to books for the do-it-yourself (DIY) market. Whether the motive is advertising or education, the most successful published materials come from sources with strong connections to the building culture and especially to the design and construction processes. Figure 1.9 Ads such as this one from the year 1882 have appeared in popular journals for as long as the journals have existed. Many modern ads refer to Web pages and/or offer free demonstration videos or compact discs (CDs). (From Builder and Wood-Worker, Vol. XVIII, Chas. D. Lakey, New York, 1882) Construction Systems For the past 150 years, most houses in North America have been built using wood light frame construction, which is the most flexible of all building systems. There is scarcely a shape it cannot be used to construct, from a plain rectilinear box to cylindrical towers to complex roofs with dormers of every description (Figure 1.10). Since it first came into use, wood light framing has served to construct buildings in styles ranging from reinterpretations of nearly all the historical fashions to uncompromising expressions of every architectural philosophy of the last 100 years. It has assimilated without difficulty a succession of technical improvements in building: gas lighting, electricity, indoor plumbing, central heating, air conditioning, thermal insulation, prefabricated components, and electronic communications. 1/25/11 3:10 PM 10 / Part One • Context Figure 1.10 The Carson House, built in 1885 in the Queen Anne style for a lumber baron in Eureka, California, is one of the most elaborate residential forms ever built and stands as a testament to the versatility of the wood light frame. (Courtesy of University of Oregon Visual Resources Collection. Original photography by Michael Shellenbarger) Wood light frame buildings are easily and swiftly constructed with a minimal investment in tools. Many observers of the building industry have criticized the supposed inefficiency of light frame construction, which is carried out largely by hand methods on the building site, yet it has successfully JWBT418-01.indd 10 fought off competition from industrialized building systems of every sort, partly by incorporating their best features, to remain the least expensive form of durable construction. However, wood light frame construction has its deficiencies: If ignited, it burns rapidly; if exposed to dampness, it decays. It expands and contracts by significant amounts in response to changes in humidity, sometimes causing chronic difficulties such as cracking plaster, sticking doors, and buckling floors. The framing itself is so unattractive to the eye that it is seldom left exposed in a building. These problems can be controlled, however, by clever design and careful workmanship, and there is no arguing with success: Frames made by the monotonous repetition of wooden joists, studs, and rafters are likely to remain the number one system of building in North America for a long time to come. The wood light frame system is described in detail in Chapters 7 to 21. If 90 percent of all site-built residential construction consists of light wood frame, the remaining 10 percent is divided among several other residential construction systems. In some regions of the South, loadbearing masonry is the dominant system. Throughout the continent, other systems such as timber frame, light-gauge steel frame, insulating concrete forms, insulated masonry, and panelized construction are used in significant numbers of dwellings. These systems are important for their roles in developing new materials and building methods and for inducing innovation in the dominant wood light frame system. These less common systems are discussed in Chapters 23 to 27. The manufactured housing industry factory-builds entire houses as finished boxes, often complete with furnishings, and trucks them to prepared foundations where they are set in place and made ready for occupancy in a matter of hours (Figure 1.11). If the house is 14 feet (4.27 m) or less in width, is constructed on a rubber-tired frame, and is completely finished in the factory, it is known as a mobile home. If wider than this, or more than one story high, it is built in two or more completed sections that are joined at the site and is known as a sectional home or modular home. Mobile homes are sold at a fraction of the price of conventionally 1/25/11 3:10 PM Chapter 1 • The Context for Construction / 11 Figure 1.11 This manufactured house was trucked to the site in sections, which were joined together as they were placed on the sitebuilt concrete foundation. The garage will be built at the site because garages, having no framed floors, are difficult to transport and are economical to frame on-site. Manufactured houses account for approximately 25 percent of all new housing in the United States. (Photo by Rob Thallon) Figure 1.12 Manufactured housing is typically single-story construction, but some companies experiment with two-story models. This house was set on the foundation within a matter of hours, but it took weeks for the site crew to add the porch, finish the trim, connect the utilities, and complete the painting. (Courtesy of Fischer SIPS, Louisville, Kentucky) (a) (b) constructed houses. This is due in part to the economies of factory production and mass marketing, and in part to the use of components that are lighter and less costly and, therefore, of substantially shorter life expectancy. At prices that more closely approach the cost of conventional on-site construction, however, many companies manufacture modular housing to the same standards as conventional construction. Manufactured housing is an important component of the housing industry but is highly specialized. Because the units are made in a factory rather than at the site, the designs are strongly driven by considerations of production and transport, and their construction process is significantly different from that of site-built housing. For these reasons, manufactured housing is given only limited coverage in this book. Types of Residential Development (c) JWBT418-01.indd 11 At the present time, houses are built in the United States at the rate of about 600,000 new units per year– less than half of the totals reached in recent peak years. Approximately 65 percent are single-family detached 1/25/11 3:10 PM 12 / Part One • Context (freestanding) dwellings, 33 percent are units within large structures (5 or more units), and the balance are in buildings with 2 to 4 units (Figure 1.13). Most new housing is built at the site, but about 130,000 manufactured houses (representing about 8 percent of the total) are built in factories and shipped to the site each year (Figure 1.14). Remodeling of 520 Figure 1.13 260 2009 U.S. housing production measured in thousands of units, broken down by the number of separate dwelling units per building. (Source: U.S. Census Bureau, 2009, Characteristics of Housing, June 2010) 13 1 Unit 2-4 Units 5+Units U.S. Housing Starts and Shipments (in thousands) 2001 2002 2003 2004 2005 2006 2007 2008 1466 1528 1630 1742 1863 1582 1142 704 New site-built singlefamily housing starts Percentage of total 1273 1359 1499 1611 1716 1465 1046 622 87 89 92 92 92 93 92 88 Manufactured homes shipped Percentage of total 193 169 131 131 147 117 96 82 13 11 8 8 8 7 8 12 Total Figure 1.14 New site-built single-family housing starts vs. manufactured-home shipments. (Source: Manufactured Housing Institute) U.S. Annual Value of U.S. Residential Construction 2007 2005 Total residential construction New residential units Residential improvements Figure 1.15 Billions of Dollars Percentage of Total Billions of Dollars Percentage of Total 647 485 162 100 75.0 25.0 531 359 172 100 67.6 32.4 Annual value of construction put in place: new housing units vs. improvements. Residential construction accounted for 44.3 percent of all construction in the United States in 2007. (Source: U.S. Census Bureau, Annual Value of Construction Put in Place in the U.S.) Privately Owned Housing Units 1995 Number of Units (1000s) 1999 2003 Percentage of Total Number of Units (1000s) Percentage of Total Number of Units (1000s) Percentage of Total All units 1313 100 1636 100 1848 100% One unit total For sale Contractor built for owner Owner built For rent 1066 682 204 146 33 81 52 16 11 2 1307 913 208 144 43 80 6 13 9 2 1499 1120 205 127 47 81% 61% 11% 7% 3% 247 51 196 19 4 15 329 54 275 20 3 17 349 51 262 19% 4% 14% Two units or more total For sale For rent Figure 1.16 Statistics for privately owned housing units completed in three separate years. (Source: U.S. Census Bureau: Characteristics of New Housing, 2003) JWBT418-01.indd 12 1/25/11 3:10 PM Chapter 1 • The Context for Construction existing houses is more difficult to quantify because it includes projects that range in scope from a new window to an addition larger than the original house. However, it is clear that remodeling is a substantial component of the residential construction industry. The U.S. Census Bureau estimates that residential remodeling in the United States in 1999 accounted for $99 billion in economic activity, about 28 percent of the value of all new residential construction (Figure 1.15). In Canada in the year 2009, more than 149,000 units were built, 51 percent of which were single-family detached houses. Houses are built for a number of different reasons, depending principally on who pays for their construction (Figure 1.16): • Many are built for personal use and are financed from start to finish by the future owner. Houses in this category are virtually always singlefamily detached dwellings, although a few are condominium units within larger buildings. • Houses may also be built for profit, either to be sold or to be rented by entrepreneurial housing developers. This activity is called speculative building and accounts for more than half of all housing units built each year. Speculative houses built for sale are most likely to be detached dwellings, whereas speculative rental housing is usually consolidated into large buildings. • Finally, low-cost houses intended for low-income families are built for the public good by government or / 13 nonprofit agencies. Like houses built for profit, affordable housing can be detached or part of a large structure, for sale or for rent. The most popular form of residence in North America has always been the single-family detached house. In 2003, 1.5 million detached units were built, representing 92 percent of all site-built residential construction activity (Figure 1.13). Symbolic of independence, family life, and a connection with nature, the singlefamily detached house has evolved through numerous styles, including Colonial, Federal, Victorian, Bungalow, and Ranch (Figure 1.17). In a survey of prospective buyers conducted by Professional Builder magazine, all respondents indicated a strong preference for the detached unit when Figure 1.17 The single-family detached house has always been the most popular type of residence in North America. It has been constructed in a variety of styles throughout its evolution. (Reproduced with permission from John Milnes Baker, A.I.A., American House Styles: A Concise Guide, New York, Norton, 1994) JWBT418-01.indd 13 1/25/11 3:10 PM 14 / Part One • Context Buyer Type Type of Home First Time Move-Up Empty Nester Retiree Detached production house 50.0 46.1 48.7 42.4 One-of-a-kind custom house 22.5 42.1 22.0 24.6 Specialty home 6.6 4.8 1.1 8.8 Modular, panelized, package home 5.3 2.6 16.2 8.6 10.1 0.6 3.7 5.2 Townhouse Mobile home 1.6 1.8 1.2 2.8 Condominium in low-rise building 1.4 — 5.9 3.0 Duplex 2.1 0.7 1.2 4.0 Condominium in high-rise building 0.5 1.3 — 0.7 Figure 1.18 In a consumer survey, several types of potential buyers were asked, "Which one type of home described is the type you would attempt to purchase if you were buying a home at the present time?" Results of surveys such as this influence the construction and design of all types of housing. (Source: Professional Builder Consumer Survey on Housing, 1998, Cahners Business Information) Figure 1.19 Tracts of identical or similar houses built at the edges of existing developments are largely responsible for the sprawl of the suburbs. Production line repetition and a dearth of landscape features contribute most significantly to the lack of character in these instant neighborhoods. (Photo © Bill Owens) offered a choice between this and an attached house such as a townhouse or condominium (Figure 1.18). This preference for detached housing has been largely responsible for the proliferation of suburbs since the end of World War II. The largest number of singlefamily houses are built in tracts of many units, where developer/ builders repeat house plans in order to reduce construction costs by means of production line repetition (Figure 1.19). In tracts, a considerable amount of time and money must be invested to obtain governmental approvals and install infrastructure such as roads, storm drains, sewers, water lines, electricity, and telecommunications before any houses can be built. This large initial investment limits the development of large and medium-sized tracts to experienced JWBT418-01.indd 14 1/25/11 3:10 PM Chapter 1 • The Context for Construction developer/builders to whom financial institutions will loan the large sums of money required for such endeavors. The design of housing tracts must conform to zoning ordinances that stipulate minimum street widths, off-street parking requirements, minimum lot sizes, minimum distances of buildings from lot lines, maximum building heights, and many other constraints. These regulations are designed to avoid infringement of any homeowner's rights and property values by the activities of other homeowners. A tract that is developed to comply completely with these regulations is called a subdivision, whether the houses are all the same or are unique (Figure 1.20). Most municipalities also have laws that allow a residential tract to be developed as a planned unit development (PUD). In a PUD, the houses are designed simultaneously with a coordinated site plan to assure privacy, individuality, visual harmony, and a pleasant neighborhood environment. A PUD generally achieves the qualities that are sought by zoning ordinances, but often does so without literally complying with them. For example, in an area where zoning ordinances call for half-acre lots, a PUD might achieve this overall density by clustering houses in tight groupings, each with a small private yard or garden, and providing generous communal open spaces between the clusters. The concept of the PUD is that, in recognition of the quality of design that can be achieved when the entire project is designed by a coordinated team of design professionals, the literal enforcement of zoning ordinances may be relaxed (Figure 1.21). Many new single-family detached houses are built on individual lots, independently of the construction of other units. These houses may be speculative projects offered for sale or may be built for or by the owner of the lot. Speculative houses on individual lots tend to be constructed by small-scale developers or by JWBT418-01.indd 15 / 15 Figure 1.20 This subdivision has streets and building lots designed to accommodate houses that vary considerably in design from one lot to the next. For the sake of efficiency, builders usually repeat several house designs again and again in each subdivision, but each design can be built in both its original configuration and its mirror image, and small cosmetic features can be introduced for variety. (Photo by Rob Thallon) Figure 1.21 The street in this PUD is narrower than normal and the garages are located close to the street in order to create an intimate feeling for the residents. Adjustments like this to zoning regulations are possible in PUDs because the entire tract is designed at the same time by a professional design team. (Photo by Rob Thallon) 1/25/11 3:10 PM 16 / Part One • Context developers who prefer the variety of experience this type of project affords. The construction of a new residence on individual lots by owners for their own occupancy is also a very common occurrence, accounting for as much as 20 percent of all new house construction (Figure 1.22). In this case, owners either hire a general contractor to manage the construction or act as the general contractor themselves. When acting as general contractor, owners may do some or most of the work themselves with the remaining work performed under their direction by subcontractors. Large multiunit structures up to four stories in height are usually built Figure 1.22 Custom-designed houses, built by or for owners on their own lots, account for about one-fifth of all residential construction. Custom-designed houses may also be built on speculation. In either case, the builder/developers of these unique houses tend to be small-volume entrepreneurs who value the challenge of variety more than that of efficient production. (Photo by Rob Thallon) Figure 1.23 A four-story apartment building under construction in an urban area. The ground floor will be commercial space, and there is a parking garage below grade. The parking and commercial levels are constructed of concrete, and the upper residential floors are constructed of manufactured wood panels lifted into place with a crane. This is a common construction type for urban multiunit housing. (Photo courtesy of Rowell/Brokaw Architects) Figure 1.24 For rental housing, the design goal is most often to maximize density within the guidelines allowed by governmental regulations. The more units there are on the site, the more income for the owner. (Photo by Rob Thallon) JWBT418-01.indd 16 1/25/11 3:10 PM Chapter 1 • The Context for Construction with the same materials and methods as single-family residences but invariably require a larger, more highly capitalized contractor to do the work (Figure 1.23). Multiunit structures are almost always built either for profit or for the public good and tend to be sited as densely as possible. In 2009, new residential structures with 5 or more units contained an average of 23 units. Because cities, counties, and other jurisdictions have regulations about how many automobile parking spaces must be provided for each unit, the number of units that can be located on a given site often depends entirely on the number of parking spaces that the site can accommodate. Without building a parking garage, the greatest density can be achieved by covering as much of the street level of a site as possible with parking and placing the living units on the second floor and above (Figure 1.24). When units are located at ground level, private outdoor yards can be obtained at the expense of density. Multiunit, multistory structures are designed and built essentially the same as single-family detached houses but have special problems: 1. The site planning process is more involved, requiring more neighborhood meetings, necessitating more permits and approvals, and taking more time than a single residence. Parking and the movement of vehicles onto and through the site strongly influence the building design. 2. Code requirements are more stringent with regard to accessibility by emergency vehicles and emergency egress by occupants. 3. Building codes require that individual units be separated by walls or floor/ceiling assemblies that are resistant to the passage of fire. Most residences in multiunit buildings are acoustically insulated as well. 4. A passenger elevator is required in most cases where buildings are three or more stories tall. JWBT418-01.indd 17 5. Where cars are parked below living units, a garage made of concrete or concrete masonry with a concrete slab ceiling is required as a way of protecting the dwellings from vehicle fires. Zoning Ordinances, Building Codes, and Other Legal Constraints Zoning Ordinances The legal restrictions on buildings begin with local zoning ordinances. The most basic purpose of zoning ordinances is to designate areas of land in a town or county for particular kinds of uses. In a town or city, some areas are designated for commercial use, some for civic use, some for schools, others for residential use, and so forth. In rural areas, zones are set aside for agriculture, for commerce, for residential development, and for other uses. Residential zones within urban boundaries are usually divided into low-, medium-, and high-density areas. The device of zoning prevents such things as automobile repair shops or slaughterhouses from being located in residential neighborhoods and creates a mix of residential densities. In residential zones, ordinances usually define minimum lot sizes, off-street parking requirements, maximum building heights, and setback requirements, which dictate how far buildings must be from each of the property lines. Zoning ordinances often contain other provisions such as treecutting restrictions, erosion control measures, fencing restrictions, solar setback requirements, and sidewalk specifications. Copies of the zoning ordinance for a municipality are available for purchase or reference at the office of the building inspector or the planning department, or they may be consulted at public libraries. / 17 Building Codes Building codes were originally developed to protect the occupants of a building from careless or unscrupulous builders. In ancient Babylon, building codes held a builder accountable for his work to the extent that he was slain if a house he had built collapsed and killed the householder. Engineers of ancient Roman arches were required to stand beneath each arch as the formwork was removed. Modern building codes still make builders and designers responsible for structural safety, but place more emphasis on checking plans and verifying workmanship during construction and less on penalizing the builder or designer for failures. Codes that regulate the design and construction of residences came into existence in the United States in response to disastrous fires and unhealthy and unsafe living conditions. One of the first codes was written in the 1630s when the governor of the colony of Massachusetts issued a proclamation forbidding the construction of wooden chimneys or the use of thatch for roofing. In 1867, the New York Tenement House Act called for fire escapes, windows for ventilation, running water within each building, and handrails on all stairways. In the 1920s, fire insurance companies were successful in setting fire safety standards for all major construction throughout the United States, and it wasn't long before other interests followed suit. The first national code intended for adoption by local and state governments, the Uniform Building Code (UBC), was first published in 1927. Since that time, there has been a proliferation of codes that prescribe minimum standards for building design and construction as well as specialized codes for plumbing, electrical wiring, fire safety, mechanical equipment, and energy efficiency. These codes were called model building codes because they were prepared by national organizations of 1/25/11 3:10 PM 18 / Part One • Context local building code officials. Their purpose was to provide models for adoption by local jurisdictions such as states, counties, and cities. In recent decades, there have been several competing model building codes. In the western United States and parts of the Midwest, most codes were modeled after the UBC. In the East and other areas of the Midwest, the Building Officials and Code Administrators (BOCA) National Building Code was the model. The Standard Building Code (SBC) was adopted by many southern and southeastern states. The specialized codes such as plumbing and electrical codes have followed a similar pattern. In recent years, the major building code organizations have published residential versions of their model codes. These specialized editions of the model codes were intended only for single-family dwellings and duplexes (two families in one building), while larger residential structures were subject to the standards in the complete codes. The residential codes were replaced in the 1990s with a single national model code created by the Council of American Building Officials (CABO), an organization with representation from all major regional code associations. The CABO One- and TwoFamily Dwelling Code, published in 1992 and 1995, combined into one document relevant standards from the model building codes as well as standards from the national model electrical and plumbing codes. Beginning in the year 2000, local code jurisdictions throughout the United States began adopting the new International Residential Code (IRC), which applies not only to oneand two-family dwellings, but also to townhouses , which are multiple single-family dwellings with separate means of egress (emergency escape). The IRC is drawn largely from its predecessor, the CABO code, and includes standards for electrical wiring, plumbing, and energy conservation. The IRC is updated every three years, JWBT418-01.indd 18 at which time it is made available for state and local jurisdictions to adopt in its entirety or after revising or excluding particular provisions. The most recent IRC revision in 2009 added a requirement that all new houses must have fire sprinkler systems, and it increased energy efficiency requirements so that new houses will theoretically perform 15 to 20 percent better than houses built to the specifications of the 2006 code. Large multifamily residential buildings with common means of emergency egress are governed by the International Building Code (IBC). The IBC is revised on the same threeyear schedule as the IRC, and it is a much larger and more complex code because it regulates the construction of all buildings except those covered by the IRC—from the corner store to the tallest skyscraper. Canada publishes its own model code, the National Building Code of Canada, the most recent version of which was issued in 2005. While these model codes for residential structures differ in detail, they are similar in approach and intent. Emergency exit requirements generally include minimum size and maximum sill height dimensions for bedroom windows to allow occupants to escape and firefighters to enter. An automatic fire alarm system, including smoke detectors, is almost universally required in residential buildings to awaken the occupants and get them moving toward the exits before the building becomes fully engulfed in flames. Automatic fire sprinkler systems are also sometimes required in residential construction, and these requirements are likely to become more widespread as simpler, less expensive sprinkler systems are developed. A typical code also establishes standards for natural light; ventilation; structural design; floor, wall, ceiling, and roof construction; chimney construction; plumbing; electrical wiring; and energy efficiency. Codes will be discussed further in each chapter as they apply. Other Legal Constraints The U.S. Occupational Safety and Health Act (OSHA) sets safety standards for construction operations. Fire insurance organizations (Underwriters Laboratories, for example) exert a major influence on construction standards through their testing and certification programs and through their rate structures for building insurance coverage, which offer strong financial incentives for more fireresistant construction. In addition, an increasing number of states have placed legal limitations on the quantities of volatile organic compounds in paints and construction adhesives that building products can release into the atmosphere. Most states and localities also have conservation laws that protect wetlands and other environmentally sensitive areas from encroachment by buildings. Multiple-unit residential buildings must adhere to legal restrictions that go beyond the building codes that apply to single-family dwellings. Access standards regulate the design of entrances, stairs, doorways, elevators, and toilet facilities for a small percentage of dwellings in multifamily residential buildings to ensure that they are accessible by physically disabled members of the population. The Americans with Disabilities Act (ADA) makes accessibility to buildings by disabled persons a civil right of all Americans. Building Costs and Financing Building Costs Every building project has a budget, which plays a crucial role in its design and construction. Costs for a typical single-family residence include the initial cost of the land, the costs of site improvements (such as a driveway, utilities, and landscaping), materials and labor to construct the building, 1/25/11 3:10 PM Chapter 1 • The Context for Construction Share of Price / 19 Average Cost 1998 2002 2004 2007 2009 2009 Finished lot cost 23.6 23.5 26.0 24.5 20.3 $ 76,591 Total construction cost $222,511 54.8 50.8 51.7 48.1 58.9 Financing cost 1.9 2.1 1.8 2.4 1.7 $ Overhead and general expenses 5.7 5.5 5.8 7.0 5.4 $ 20,377 Marketing cost 1.4 2.4 1.9 2.5 1.4 $ 6,375 5,297 Sales commission 3.4 3.7 3.0 4.3 3.4 $ 12,815 Profit 9.2 12.0 9.8 11.2 8.9 $ 33,658 100.0 100.0 100.0 100.0 100.0 $377,624 Total sales price Figure 1.25 The construction industry is constantly tracking construction costs. This table shows the cost of doing business as a residential developer/builder as a percentage of total unit cost. The cost of design is in the "overhead" category. (Source: NAHB Construction Cost Survey) building plans or design fees, building permit(s), and the cost of financing (Figure 1.25). There are rules of thumb that can be used to make estimates for these various costs and to create a pro forma, which is a comprehensive analysis of estimated costs and returns to establish the feasibility of a proposed project. Once a project begins, there is a series of conversations among the owner, the designer, and the contractor in order to establish precise costs and allocate resources appropriately. In some cases, the owner buys generic plans and deals directly with contractors to establish prices and maintain quality. A construction cost can be established either by negotiating with a single contractor or by means of a competitive bidding process among several contractors. In other cases, the owner employs an architect or designer who makes early estimates of construction costs based on rules of thumb and later consults with contractors during the negotiating or bidding process to establish more accurate cost projections (Figure 1.26). In all cases, it is ultimately the owner who makes the decisions that affect the cost and the design of a project. JWBT418-01.indd 19 Item Area Unit Cost Cost Main floor 1,853 $155 $287,200 Second floor 1,294 $145 $187,630 Basement 631 $ 40 $ 25,240 Porches (first floor) 270 $ 60 $ 16,200 Porch (second floor) 112 $ 75 $ Garage 528 $ 75 $ 39,600 Connector 300 $ 60 Building Total 8,400 $ 18,000 $582,270 Architectural fees $ 54,000 Engineering $ 2,600 Permits $ 4,000 Systems development fees $ 4,000 Site septic $ 4,000 Road $ 6,500 Landscape $ 26,000 Project total $683,370 Figure 1.26 A cost estimate done by an architect for a client in the year 2007. This type of estimate is based on cost per square foot and is done early in the design process. A contractor will later determine the actual cost of the house based on bids from subcontractors. Construction costs vary considerably from region to region, and permit fees can vary significantly according to the jurisdiction. 1/25/11 3:10 PM 20 / Part One • Context There are a number of variables that must be considered when determining the cost of a residential building project. The most important of these are the overall size, the complexity of the design, and the quality of materials. Larger houses are generally more expensive than smaller houses, but the cost per square foot tends to be lower for larger houses because of the economy of scale. Design complexity can have a significant effect on construction cost. Keeping the overall building form simple and respecting the modular sizes of standard materials are key principles in projects where affordability is a primary objective. Material selection can also have a huge impact on budget because material costs vary so considerably. The cost of a simple residence made with the most affordable materials can easily be doubled if the same residence is built with more luxurious materials. Owners must often grapple with the difference between first cost and long-term value. The first cost is the initial cost of construction, and the Monthly Expenses Mortgage Fuel Total Base case home $1057 $ 124 $1181 Passive home $1082 $ 74 $1156 Difference $ +25 $−50 $ −25 Figure 1.28 A first-cost vs. life-cycle analysis comparing two 2124-square-foot houses in New York State, one with an attached sunspace and additional insulation. The first cost of the sunspace and insulation was $4400, which translated to an additional $25 monthly mortgage payment. With fuel savings, however, the total monthly expenditures for the passive home were $25 less than those of the base home, and the initial additional outlay was recovered in less than 3 years (and has additional amenities). (Source: The Passive Solar Design and Construction Handbook, Steven Winter Associates, Michael J. Crosbie, Editor, John Wiley & Sons, Hoboken, New Jersey, 2009) tendency of owners is to keep this cost as low as possible. Unfortunately, a low first cost frequently leads to more expenditure in the long run. More insulation in the walls of a house, for example, can lead to lower heating and cooling bills that can recoup the initial extra investment in a short time (Figure 1.28). Higher-quality materials can require less maintenance and add to the overall value of a house when it is sold. Numerous examples such as these have led to the practice of life-cycle cost analysis, which is a long-term analysis of construction, operation, and maintenance costs, and is often employed in large-scale projects. Large residential subdivision projects and multifamily structures follow the same cost analysis procedures as a single-family house except that the cost of site development is a much larger percentage of the cost of the overall project, so more evaluation is required in this area. The amount of building construction is also more extensive in large projects, so the stakes are higher and much more attention is given to repetition of house or apartment designs in order to gain the advantages of the assembly line. Financing Figure 1.27 Family cabins and second homes form a significant part of the housing market. Their design often references historical or rustic precedents to create an atmosphere different from that of everyday life in the city or the suburbs. (Photo by Rob Thallon) JWBT418-01.indd 20 Building a house is such an expensive endeavor that almost no one can afford to pay for it out of pocket. Banks and savings and loan institutions are in the business of lending money for this significant investment in return for interest, which is a rental cost for the money expressed as a percentage of the amount loaned. In order 1/25/11 3:10 PM Chapter 1 • The Context for Construction to make a loan on the construction of a house, a bank needs to be convinced that the owner has the financial capacity to repay the loan over time and that the house can be resold to pay off the loan if the owner should fail to make the loan payments. The bank assesses the owner's ability to make loan payments on the basis of investigation of the owner's credit record and the evaluation of recent tax returns. Owners often will prequalify for a loan up to a certain amount in order to establish a project budget before the house is designed. The projected resale value of a house has a tremendous impact on how much financing a bank will provide or if financing will be provided at all. In order to establish resale value, an official of the bank appraises the building based on plans and material specifications and adds the value of the lot to arrive at a total appraised value of the developed property as proposed. To minimize their risk, banks usually require that the owner invest at least 20 percent of the appraised value of a project. The traditional mechanism used to finance the construction of a house is the combination of a construction loan while the house is being built and a permanent mortgage for the period thereafter. The construction loan is generally limited to a period of 9 months or less and has an interest rate that is higher than the permanent mortgage. As construction proceeds, progress is verified by an agent of the bank, and funds from the construction loan are disbursed to the contractor. The permanent mortgage goes into effect after construction has been completed and runs for a period that may range from 15 to 30 years with payments due to the bank every month. These two loans can be consolidated into a single all-in-one loan that is negotiated before construction begins at a single prevailing interest rate and avoids the duplication of closing costs and other costs associated with dual-loan agreements. JWBT418-01.indd 21 Environmental Responsibility: Building Green As expanding populations and diminishing resources begin to produce global-scale environmental impacts, there are many who see the need for a more environmentally aware approach to the way we design and build our houses. The construction of well over a million new houses per year represents the consumption of unimaginable amounts of raw materials, the emission of uncountable tons of toxic chemicals, and huge long-term energy requirements. Even a relatively small shift in the way these houses are designed and built can have a significant impact on resources and on the lives of those directly affected by their construction (Figure 1.29). Those concerned with the environmental consequences of new construction have organized into various groups that promote the cause of what they commonly call green building. The green building movement generally has a comprehensive approach to improving the situation that includes three strategies: 1. Improve the energy efficiency of buildings by designing and building them to use less energy to heat and cool. Material Weight (lb) Solid sawn wood 1600 Engineered wood 1400 Drywall 2000 Cardboard 600 Metals 150 Vinyl (PVC) 150 Masonry Containers Other Total / 21 2. Improve the resource efficiency of buildings by using fewer and better materials in their construction. 3. Lower the toxicity of new buildings to minimize health risks to workers and occupants. Many of these strategies increase the cost of constructing a new house, but proponents of environmental responsibility see no alternative in the long run and point out that consumers are increasingly aware of the issues and expect some response by those who design and build the houses they buy. As the volume of green building activity increases, its cost premiums will decrease. A discussion of green building can be found in a special section at the end of most chapters of this book. Energy Efficiency Environmentally responsible designers can have a large impact on the long-term energy consumption of a house. Reduction of energy consumption starts by making the house no larger than needed and by increasing thermal insulation and other weatherizing elements beyond codemandated minimums. The shape of the building and its orientation can be modified to provide possibilities for passive solar heating and passive cooling (Figures 1.30 and 1.31). In Figure 1.29 Typical construction waste for a new 2000-square-foot house. Siding material was assumed to be vinyl on three sides and brick on the street side. (Source: NAHB, Residential Construction Waste: From Disposal to Management) 1000 50 1050 8000 1/25/11 3:10 PM 22 / Part One • Context fact, a thoughtful response by the designer to the climate and microclimate can have more impact on environmental issues than any other design act for a house of a given size. In addition, the selection of an efficient mechanical system can make a big difference in the amount of energy consumed for heating and cooling. Low-volume plumbing fixtures conserve water and lower the volume of sewage that needs to be treated. Resource Efficiency Figure 1.30 This passive solar house, designed by architect Michael Utsey and built in 1976, employs south-facing glass, interior thermal mass, and extra insulation to reduce heating and cooling costs. Still popular as a strategy, passive solar heating and cooling have received a new impetus in recent years from the green building movement, whose goals relate more generally to the environment and to human health. (Photo © Jane Lidz) The first step toward resource efficiency is to make the house as small as is practical; beyond this, a number of smaller steps can also be taken. The use of lumber that has been harvested from a certified sustainable-yield forest protects timber as a resource and lessens the pressure to harvest from natural forests with volatile ecosystems. The use of materials with minimal embodied energy, which is a measure of all the energy it takes to produce and transport a building product, contributes to overall energy conservation. The use of materials with recycled content such as carpet made of recycled beverage containers and building panels made of recycled newspapers reduces the demand for natural resources and diminishes the volume of landfill (Figure 1.32). The detailing of the house to eliminate structural framing where it is not required and designing to take advantage of the standard dimensions of building materials can save material, reduce labor costs, and minimize construction waste. Finally, the use of materials that can be recycled easily when the house is ultimately remodeled or demolished will save energy and materials in the future. Low Toxicity Figure 1.31 A house exhibited on a passive solar home tour in the year 2006. The principles of passive solar design have remained constant in the 30 years since the house in Figure 1.30 was built, but materials and techniques have improved. (Photo by John Reynolds) JWBT418-01.indd 22 Environmentally conscious builders use materials that do not emit dangerous chemicals over their lifetime. Carpeting is often a big offender in this regard because of the adhesives 1/25/11 3:10 PM Chapter 1 • The Context for Construction / 23 Figure 1.32 House moving exemplifies the ultimate recycling of building materials. It is surprising how many worthy buildings have been saved from the wrecking ball by this practice. (Photo by Rodney Douglas II for Chris Schoap Building Movers) used to bond some types of fibers. Certain panel products used for subflooring and cabinet cores have been notorious for emitting harmful formaldehyde gas, but formaldehyde-free panels are now manufactured and need only be specified. Paint used to have a high lead content, but this situation has been corrected through the efforts of concerned citizens. However, many paints still contain high levels of volatile organic compounds (VOCs), which are extremely unhealthy for painters, pose health risks for future occupants, and pollute the atmosphere. Paint manufacturers have been developing more and more water-based coatings that are just as durable as solvent-based coatings but have much lower VOC levels. The issue of toxic building materials was first raised by people with extremely high sensitivity who were falling ill due to the various emitted gases. The health dangers from these materials were communicated to the general public by environmental advocates and alert journalists, and manufacturers and builders have responded, but the response has been slow, and much work remains for the green building movement to accomplish. JWBT418-01.indd 23 Building a House: The Typical Process The construction of a house involves a series of steps that vary somewhat from project to project but that typically follow a similar path (Figure 1.33). This path is outlined in the paragraphs that follow and is described in detail for a typical wood light frame house in Chapters 7 to 21. For large subdivision or multiplefamily projects, the first steps are typically considerably more complicated, but once framing begins, the only significant difference between a large project and a single-family project is one of scale. Building Permits and Inspections After the construction documents have been completed, the first step in the construction process is the application for a building permit. Plans for the building along with engineering calculations and energy compliance forms are submitted to the city or county building department where they are reviewed by various plans examiners for compliance with local zoning ordinances and building codes. Plans examiners are trained to be comprehensive in their review, which includes many issues of health, safety, energy conservation, and environmental protection. When the review has been completed, any necessary corrections have been made, and all fees have been paid, a permit for construction is issued. As construction proceeds, inspections are requested by the contractor at designated stages of construction, in response to which the building department sends an inspector to verify the quality of the work and its correspondence with the approved plans. Building inspectors are not the same people as plans examiners, although they work for the same agency and their inspections are based on approved plans that are required to be on the site. But inspectors see the completed work in place, so they approve the work or not depending on whether all the details of a particular phase have been completed to their satisfaction. There are usually between 15 and 20 inspections required to build a new house, and the approval of each phase is usually necessary in order to begin the next. 1/25/11 3:10 PM 24 / Part One • Context The bulk of the inspections are conducted by the building inspector, who works for the city or county agency that issues the permit, but there are also specialized inspectors such as a plumbing inspector or electrical inspector who may work for state agencies. Once all the inspections have been passed, the building department will issue a certificate of occupancy, which will allow the new construction to be occupied. Building Site Preparation The Foundation Preparation of the building site for construction is the first physical step in the building process. The area of the site to be occupied by the house is cleared, the building is located and its corners staked, and a hole is excavated for the foundation. In addition, utilities such as electrical power, water, gas, and phone lines are extended to the building site. Sewage and storm drain lines are installed. Construction of a foundation to transmit the weight of the building into the earth is the next step in the construction process. Foundations can range from a concrete slab poured on top of the ground to a basement excavated deeply into the site. Foundations for large multifamily buildings often incorporate parking garages and thus involve much more complicated construction. Contractors Schedule Category Temporary facilities Site work Excavation Debris removal Concrete Figure 1.33 Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 A typical schedule of the work for an average-sized house. Notice how many different trades are at the site during the last week of construction. (Courtesy of Treeborn Carpentry, Eugene, Oregon) Footings and foundation Slabs Masonry Carpentry Framing and exterior trim Interior finish Exterior structures Thermal and moisture protection Insulation Waterproofing Roofing Sheetmetal Drywall and plaster Interior plaster, drywall Doors and windows Cabinetry Paint Finish surfaces Tile Counters Vinyl/Carpet Wood flooring Mechanical Plumbing Electrical HVAC Inspections JWBT418-01.indd 24 1/25/11 3:10 PM Chapter 1 • The Context for Construction / 25 Structural Framing When the foundation is in place, the framing can proceed. With a slab foundation that acts as a floor, framing begins with the walls. When there is no slab, a wooden floor structure is constructed on the foundation. A framing crew builds the walls, floors, and roof with lumber and structural wooden panels (Figure 1.35). Roofing and Siding Figure 1.34 A typical perimeter foundation around a crawlspace. Underfloor plumbing, heating/ cooling ducts, and first-floor framing have been completed, and soil has been backfilled around the foundation. Next the floor deck will be laid, and wall framing will begin. (Photo by Rob Thallon) Exterior finish materials are applied to the completed framing to make the building weathertight and durable. Roofing is applied to the roof, and provisions are made to gather rainwater from the roof and channel it away from the building. Windows and doors are installed, and the walls are covered with siding. Any required exterior painting is done. With roofing and siding in place, the building is "tight to the weather," and the overall project is about 50 percent complete (Figure 1.37). Figure 1.35 The newly begun house in the foreground stands silhouetted against a fully framed house. The roof of the framed house has been covered with building paper and the windows have been installed to protect the inside so that interior work can proceed protected from the weather. (Photo by Rob Thallon) JWBT418-01.indd 25 1/25/11 3:10 PM 26 / Part One • Context Figure 1.36 Large-scale residential projects often employ the same wood light frame technology as single-family residences. Separation between the units to inhibit the rapid spread of fire is achieved with gypsum board panels. (Photo by Rob Thallon) Figure 1.37 The roofing, windows, doors, siding, gutters, and downspouts complete the weather envelope at the exterior of the structural frame. These workers are applying the last of the siding. (Photo by Rob Thallon) JWBT418-01.indd 26 1/25/11 3:10 PM Chapter 1 • The Context for Construction Utilities and Insulation Interior and Exterior Finish While the exterior of the house is being finished, the interior utility systems are installed. First the plumbing, then the heating and cooling ductwork, and finally the electrical wiring are installed within the cavities between the studs, joists, and other framing members (Figure 1.38). When these systems are all in place and fastened to the framing, thermal insulation is placed into the cavities between the studs of exterior walls and ceiling joists to form a continuous thermal envelope around the perimeter of the house. Upon completion of the thermal insulation, the studs and other framing are covered with interior finish materials, which are immediately painted. Next the flooring and cabinets are installed and trim is fastened around floors, doors, and windows to cover the gaps between the various materials (Figure 1.39). To complete the interior of the house, the finish hardware, plumbing fixtures, and electrical trim are installed, and all remaining unfinished surfaces receive a protective coat of paint, stain, or varnish. Simultaneously with the finishing of / 27 the interior of the house, the sitework is completed with the installation of paving, decks and terraces, irrigation system, fencing, and planting. After the house is occupied, adjustments are often needed, such as balancing the heating/cooling system according to the occupants' preference, adjusting the operation of doors and windows, touching up the paint, and explaining the operating and care instructions for equipment. In most regions, the contractor must warranty the quality of the construction for 1 year after initial occupation of the house. Figure 1.38 The plumbing, heating/cooling system, and electrical wiring are installed inside the house before the walls and ceiling are insulated and covered with a finish surface. (Photo by Greg Thomson) JWBT418-01.indd 27 1/25/11 3:10 PM 28 / Part One • Context Figure 1.39 Finishing the interior of a house involves workers from more than half of the building trades, some of whom are returning to the job for the second or third time. Drywall hangers and tapers, floor installers, tilesetters, cabinetmakers, finish carpenters, painters, plumbers, electricians, and others are required to complete the work. (Photo by Rob Thallon) Figure 1.40 The W. G. Low House, built in Bristol, Rhode Island, in 1887 to the design of architects McKim, Mead, and White, illustrates both the essential simplicity of wood light framing and the complexity of which it is capable. (Photo by Wayne Andrews) JWBT418-01.indd 28 1/25/11 3:10 PM Chapter 1 • The Context for Construction / 29 SELECTED REFERENCES 1. Gideon, Sigfried, and Bobenhausen, William. American Building: The Environmental Forces That Shape It. New York: Oxford University Press, 1999. Connects the environment, the act of building, and human nature. The classic discussion of the evolution of American architecture at all scales. 2. Davis, Howard. The Culture of Building. New York: Oxford University Press, 1999. Elegantly written and beautifully illustrated, this book describes a global building culture that is evaluated for its ability to produce a vital built environment. North American building culture is explored in depth and can be more profoundly understood in the context of examples from other parts of the world. 3. Wright, Gwendolyn. Building the Dream: A Social History of Housing in America. Cambridge, MA: MIT Press, 1983. A scholarly classic describing the reasons behind the form of most American housing. More about social history than about building. 4. International Code Council, Inc. 2009 International Residential Code for One- and Two-Family Dwellings. This is the model code for all aspects of residential construction, including detached houses, duplexes, and townhouses. Updated regularly. 5. Periodicals are an excellent source for learning about current thinking in the residential building culture. Fine Homebuilding and The Journal of Light Construction focus on construction techniques and also have articles about tools, materials, and design. Builder and Professional Builder focus on marketing and business and also have articles about materials and design. 6. Environmental Building News, a periodical published monthly for the past 18 years, is the most respected voice of the environmental building movement. Articles range from site selection to evaluation of the environmental impact of roofing materials. speculative building affordable housing single-family detached house tract subdivision planned unit development (PUD) multiunit structure setback requirements model building code Council of American Building Officials (CABO) International Residential Code (IRC) townhouse egress International Building Code (IBC) National Building Code of Canada Occupational Safety and Health Act (OSHA) Americans with Disabilities Act (ADA) first cost long-term value life-cycle cost analysis resale value appraised value construction loan permanent mortgage all-in-one loan green building sustainable-yield forest embodied energy recycled content volatile organic compound (VOC) plans examiner building inspector certificate of occupancy 3. Compare a PUD with a tract development. 6. Explain the general concept of green building. What are the particular steps a builder can take to implement the principles of green building? KEY TERMS AND CONCEPTS wood light frame contractor subcontractor builder developer designer manufacturer realtor listing agreement zoning ordinance building code American Institute of Architects (AIA) National Association of Home Builders (NAHB) manufactured housing mobile home sectional home modular home REVIEW QUESTIONS 1. Who are the professionals involved with the production of a typical speculative house from conception to occupation by the owner? How do the participants change if the house is built for the owners on their own property? 2. What are the differences between sitebuilt and manufactured housing? 4. What are the advantages and disadvantages of multiunit development from the point of view of the developer? 5. Explain the differences between zoning ordinances and building codes. Give examples of specific provisions of each. 7. Describe the typical construction process. EXERCISES 1. Have each class member interview a residential builder to determine the type of work he or she typically undertakes. Discuss the range of responses in class. 2. Repeat the preceding exercise for residential architects and building designers. 3. Obtain copies of your local zoning ordinances and building code (they may JWBT418-01.indd 29 be in your library). Look up the applicable provisions of these documents for a house on a specific site. What setbacks are required? How tall can the house be? How many cars must be able to be parked on the site? What are the requirements for emergency egress from the house? 4. Examine ads in your local phone directory or inquire at the local chapter of the NAHB to find builders who specialize in green building. Interview the green builder(s) to determine how their work differs from common practice. What different measures would they like to institute that they are not able to use now? 1/25/11 3:10 PM JWBT418-02.indd 30 1/25/11 3:11 PM 2 The C onst r ucti on C ommunity : Buil de rs, C ont rac tors, and Devel op ers • History • Builders and Contractors Types of Builders and Contractors Sizes of Companies Contractors and Subcontractors Licensing of Builders • Obtaining Work Competitive Bidding Direct Hiring Contract Formats Responsibilities of the Contractor • The Residential Developer Financing Builders as Designers Marketing and Selling • Training the Construction Community On-the-Job Training Apprenticeships Trade Schools Builder Associations MasterFormat Publications • Green Builders, Contractors, and Developers The Developer The Developer/Builder 31 JWBT418-02.indd 31 1/25/11 3:11 PM 32 / Part One • Context History Builders in North America have always been industrious and inventive. The colonists, arriving in a land without permanent buildings or a labor force to construct them, had to do all the work themselves, so they were driven to devise labor-saving processes. Thus, North America had water-powered lumber mills even before the mother country, England, did, and brickyards and foundries were created in the colonies despite discouragement by the British Crown. In the beginning, American builders adapted imported European building methods to their more severe climate, but later, they invented an entirely new system that was more flexible, used materials more efficiently, and was easier to construct. This new system, the wood light frame, has been the predominant system of residential construction for over 150 years and remains so today, even as creative builders experiment with new systems (Chapters 23 to 27). There has been specialization in the building industry since it was established early in the life of the American colonies. The first houses were constructed by carpenters who made the basic structure of wood and masons who laid foundations and made the fireplaces of stone or brick. The specialized trades of window and door making, roofing, plastering, and painting soon evolved. In the late 1800s, when utilities were introduced into the house, plumbers, gas fitters, and electricians were added to the list of specialists. Today, there are between 15 and 20 specialized trades that work on the average new residence (Figure 2.1). Standardization of building components and the building process increases productivity, which translates into increased profit for professional builders. Standard-sized bricks were typically used rather than random sizes of stone for masonry in early buildings because the regular bricks could be laid faster, with a repetitive motion. JWBT418-02.indd 32 Standard-sized doors, windows, and other components were adopted at an early date because they made construction easier and communication between builders and material suppliers simpler. The concept of standardization of the entire building process as an assembly line, introduced in the 20th century, was the ultimate step to speed on-site production. Nowhere were the benefits of assembly-line production demonstrated more dramatically than at Levittown, a suburban New York development built in the late 1940s, where the developer organized the construction process into 27 distinct steps and prefabricated every possible part of the house Figure 2.1 In the late 19th century, builders had more responsibility for and control over the design of a house because there were virtually no codes or residential designers. (Photo by Edward Allen) 1/25/11 3:11 PM Chapter 2 • The Construction Community: Builders, Contractors, and Developers in a shop (Figure 2.2). At the peak of production, the builders of Levittown built 30 houses per day. Since that time, many labor-saving devices such as the backhoe, the concrete pump, and the pneumatic nailer have further increased the speed of residential construction. The introduction of factory-assembled components such as engineered roof trusses and prefabricated fireplaces has reduced the on-site labor required to construct a new house even more. Construction efficiency has reached the point that, in 2004, the largest residential builder in the United States produced over 105 houses per day (Figure 2.3). Builders and Contractors A builder is someone who engages in the activity of constructing buildings. A contractor, on the other hand, is someone who enters into a legal relationship with an owner of a property to build the owner's building or perform other work. Under these definitions, not all builders are contractors, / 33 because some builders construct houses for sale and are not under contract to an owner. Neither are all contractors builders, because some, such as landscape contractors, do not engage in the act of making buildings. Further confusion arises because the term "builder" is also used loosely to mean both builder and contractor and specifically to refer to a speculative builder. In the discussion that follows, we will use the term "builder" in the general sense to refer to residential builders and will qualify the term when referring to a specific group. Figure 2.2 Capitalizing on the high demand for housing after World War II, Bill Levitt streamlined the residential construction process to produce Levittown, New York. The largest development ever constructed by a single builder, Levittown has 17,400 houses and about 82,000 residents. As originally built, there were five variations of the Cape Cod–style house, each with about 750 square feet, 2 bedrooms, 1½ bathrooms, and a fireplace. A similar Levittown of 16,000 houses was later built in Pennsylvania. (Courtesy of Nassau County Museums Collection, Long Island Studies Institute at Hofstra University) JWBT418-02.indd 33 1/25/11 3:11 PM 34 / Part One • Context Types of Builders and Contractors There is a significant distinction between builders who produce new residences for sale on the open market and those who work for a property owner to build a new house or remodel or repair an existing one. The former take on more responsibility than other builders—procuring land for construction, arranging construction financing, obtaining a design, and selling the completed dwelling. These builders are entrepreneurs and assume responsibility for making decisions about a product that must be attractive to consumers. If the product does not sell at a fair price, the builder will fail to make a profit. This endeavor Figure 2.3 Large-volume residential builders compete in the marketplace by carefully managing the production of houses that are designed to be easy to construct. The same designs are repeated over and over to maximize production line efficiency. (Photo by Rob Thallon) Figure 2.4 Labor-saving equipment speeds the construction process considerably. At an efficiently organized site, the same boom truck that delivers trusses to the roof also lifts a tub/shower enclosure into place on the second floor. (Photo by Rob Thallon) JWBT418-02.indd 34 involves a certain amount of speculation, and therefore these builders are called speculative builders. The latter category of builder, called a contract builder or contractor, is under contract to an owner and takes the risk that no profit will be made if the construction work under contract takes more time or costs more than anticipated. It obviously behooves both types of builders to run their businesses efficiently in order to make a profit, but the speculative builder has the potential to recoup losses from inefficiencies by raising the selling price of the finished house. Another important difference between builders relates to whether they do new construction or remodeling and/ or repair to existing houses. Both speculative builders and contractors can specialize in either type of construction, and many do both. Remodeling contractors generally work on smaller projects and have smaller companies than those who do new work because all the work is custom, precluding large-volume production. Likewise, contractors who specialize in building new custom-designed houses have limited production because each project is unique (Figure 2.5). Large-volume production of new houses is achieved by working on large tracts of repetitive units, and contractors achieve success in this arena by managing labor and materials on the building site as they would a housing production line in a factory (Figure 2.6). Sizes of Companies The National Association of Home Builders (NAHB) has categorized building companies into three groups according to size. Those building fewer than 25 units per year are small builders, those building 26 to 100 units per year are medium builders, and those building more than 100 units per year are large builders (Figure 2.7). In 2007, small builders accounted for 96.7 percent of all NAHB member builders, having increased their share of the total by 38 percent since 1970 (Figure 2.8). Although small builders 1/25/11 3:11 PM Chapter 2 • The Construction Community: Builders, Contractors, and Developers / 35 Figure 2.5 Custom-designed houses such as this take much longer to build than do tract houses designed for efficient construction. Custom-designed houses tend to be constructed by small-volume builders who complete only a few projects in a year. (Architect: David Edrington. Photo by Rob Thallon) Figure 2.6 Foundation in the foreground, framed house across the street, and finished shell in the distance. Large-volume builders organize house construction as a portable production line. By keeping subcontractors busy without having to travel between jobs, builders can obtain their services for less and offer their houses at competitive prices. (Photo by Rob Thallon) Figure 2.7 Large-volume builders consume materials so rapidly that they prefer to store them adjacent to the houses being constructed. Here lumber and other materials are stored on developed building lots for use in houses being constructed across the street. Notice the job shack, equipment and material storage trailer, and backhoe in the background. (Photo by Rob Thallon) JWBT418-02.indd 35 1/25/11 3:11 PM 36 / Part One • Context Single Family Size of Builder Number of Percentage Builders of Total Multifamily Starts per Year Percentage of Total Number of Percentage Builders of Total Starts per Percentage Year of Total Small volume (1–24 starts per year) 73,552 93.0 331,970 38.8 3,329 67.5 30,268 9.5 Medium volume (25–99 starts per year) 4,338 5.6 182,812 21.3 831 18.8 43,216 13.6 Large volume (100+ starts per year) 1,212 1.5 341,841 39.9 772 15.7 244,746 76.9 Figure 2.8 Builder size as related to number and type of housing starts in the United States. A small number of large builders account for the greatest percentage of residential building starts. (Source: U.S. Census Bureau, 2007 Economic Census, Sector 23: Construction) Figure 2.9 The management of multiple subcontractors is a principal task of every residential construction project. The goal is to keep the work moving as rapidly as possible while avoiding conflicts between trades. Larger projects enjoy an economy of scale but have unique challenges because of their size. (Photo by Rob Thallon) Size of Builder Price of House <$75,000 $75,000–$99,999 $100,000–$149,999 $150,000–$199,999 $200,000–$249,999 $250,000–$499,999 $500,000 and over Median Small Volume (<25 units/year) Medium Volume (25–99 units/year) Large Volume (100+ units/year) Total 4 10 22 36 9 14 5 $169,444 10 19 31 19 11 8 2 $133,890 7 22 33 22 10 5 — $140,000 7 19 30 24 10 8 2 — Figure 2.1