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The Cost Effectiveness of Alpha SPF Roofs: Casa View Elementary School Roofing Case Study

The performance of the Alpha Sprayed Polyurethane Foam (SPF) roofing system is perceived as an uneconomical option when compared to a 20-year modified roofing system. Today, the majority of roofs are being replaced, rather than newly installed. The coating manufacturer, Neogard, implemented the Alpha roofing program to identify the best contractors in the industry and to measure their roof performance. The Alpha roof system has shown consistent high performance on over 230 million square feet of surveyed roofs. The authors propose to identify if the Alpha roof system is renewable, has proven, competitive performance compared to the traditional modified roofing system, and is a more economical option by testing a 29-year-old Alpha roof system. The Casa View Elementary School roof system was installed with a Neogard Permathane roof system in 1987. This roof was hail tested with ten drops from 17 feet 9 inches of 1-3/4-inch steel ball (9 out of 10 passed) and four drops from 17 feet 9 inches with a 3-inch diameter steel ball (1 out of 3 passed). Over the 40-year service life, the main difference of purchasing a 61,000 square feet Alpha SPF roof versus modified bitumen roof are savings of approximately $1,067,500.


Introduction
The performance of the Alpha Sprayed Polyurethane Foam (SPF) roofing system is perceived as an uneconomical option when compared to a 20 year modified roofing system. Roof installation websites claim that SPF roofs require more maintenance than modified bitumen and recoating every 10 years (Improvenet, 2014). Additionally, other sites claim that based off of cost and maintenance, built up roofs and modified bitumen are the best value, lasting up to 30 years (Maintenance Solutions, 2015). According to Mike Smith, a roofing expert for Dallas Independent School District (DISD), the average price to apply a traditional modified bitumen roof with tear off on a commercial building is approximately $16 to $19 per square foot. Today, the majority of roofs are being replaced, rather than newly installed, and the prices of replacing a modified bitumen system are far greater than the cost of a performing Alpha SPF roofing system. SPF roofing requires significant contractor expertise in order to provide a high performance roofing system. Installation workmanship is one of the major reasons for SPF roofing defects. These SPF roofing defects can severely minimize the service period (Alumbaugh et. al, 1984;Kashiwagi & Tisthammer, 2002). In the past, it was common for the coating and SPF manufacturers to offer warranties but not honor those warranties, blaming the contractor. The poor performance of the SPF roof system has relegated the SPF roof system to 3% of the roofing market share in the United States (Kashiwagi, 2016).
In order to combat the stereotype of the SPF roofing system providing poor performance and low quality, the coating manufacturer, Neogard, implemented the Alpha roofing program to identify the best contractors in the industry and to measure the performance of their roofs. As a result of Neogard's motivation to change the industry, the performance on Alpha roofing system has been heavily documented. These performance metrics document significant results in the SPF roofing industry. The Alpha roof system has shown consistent high performance (9.5 out of 10 customer satisfaction rating and 99% of customers saying they would purchase an Alpha roof system again) on over 230 million square feet of surveyed roof. Neogard's Alpha roofing system's past performance outmatches any other roofing system's performance history.
The Alpha SPF roof system has the following attributes (Kashiwagi, 2016;Kashiwagi, 2015): SPF roofing has an R-value of R6 per inch and is used by the owners of the building as a recovery system over existing roofs including built-up roof [BUR], modified bitumen, concrete, wood, asphalt shingles, clay tile, and metal (Knowles, 2005). The advantage of the Alpha SPF roof system is that it does not require the removal of the existing modified or BUR system saving owners as much as $6/SF [50% less than the traditional BUR system] in removal costs and costs of a new modified or BUR system. A properly installed Alpha roof system has been documented to resist up to 4 inch diameter simulated hail stones [four inch diameter steel ball dropped from more than 17-3/4 feet height]. (Kashiwagi, 2015, Kashiwagi andSavicky, 2003) Problem The Alpha roof system was being questioned as being non-renewable, not having the proven performance that competes with the traditional modified roofing system, and not being an uneconomical option.

Proposal
The authors propose to identify if the Alpha roof system is renewable, has proven performance that competes with the traditional modified roofing system, and is a more economical option by testing out the performance of a 29 year old Alpha roof system.

Research Methodology
The research will be conducted as follows: 1. Identify the existing roof characteristics of the Casa View Elementary School roof. 2. Hail test the Casa View Roof with 1-3/4 inch steel ball as specified by FM-SH test. 3. Identify if the 10 drops pass the test requirement. 4. Identify if any of the drops do not pass the requirement due to extenuating circumstances such as insufficient coating. 5. Analyze the indentations of the hail drops. 6. Use a larger 3 inch diameter steel ball with OSH 2.75 hail tests to identify if the roof is potentially more robust than the perceived capability to pass the 1-3/4 inch test. 7. Run a lab test of a SPF core sample of the Casa View roof in the hail tested areas that passed and failed.

Research Findings
Casa View Roof characteristics. Casa View roof system [61K SF roof area] was installed with a Neogard Permathane roof system in 1987. This means that the roof was 29 years old at the time of the visit. The authors performed a roof inspection on the Casa View Elementary school roof on June 27, 2016. On the 61,000 sq. foot roof, there was a total of 774 square feet of blisters, 65 penetrations, 102 sq. feet of delamination, and 6,000 square feet of repairs on the roof.  As is common with an older roof, the granules had worn off of the roof, and due to rain and hail frequently occurring in June, there was some ponding. The areas with extended ponding increased blisters. The repairs were applied mostly to the edges of the roof, most likely due to higher exposure to the heavy rainfall and runoff. The Alpha system installed with proper slope and drainage improves performance, and will result in fewer repairs. The Casa View Elementary School has the following roof characteristics:

Cost of Alpha SPF versus modified bitumen
The cost of recoating and continuing the Alpha roof system of the Casa View roof will be approximately $6.00 per square foot for a SPF recoat. The cost of tearing off the existing system and installing a new traditional modified bitumen roof will be approximately $16 per square foot. The Casa View Elementary School roof is 61,100 SF. Since there was a sunk cost already incurred to DISD with the installation of the roof, the only values to document was the current decision to recoat or to tear off the existing roof and install a traditional modified bitumen system. The Alpha recoat of Casa View's roof at $6/SF would cost $366,000 with a 15 year warranty (lasting 45 years), and the installation of a traditional modified bitumen roof at $16/SF with a 20-year warranty would cost $976,000 (lasting 50 years). Based on total costs, opting to install an Alpha recoat would result in a cost savings of $610,000 and cuts the cost down by 62.5% on the project, assuming that each roof lasts the same amount of time. The yearly cost of $24,400 for the Alpha recoat with a 15-year warranty ($366,000/15) would be 50% less than the yearly cost of $48,800 for a 20-year warranty for a traditional modified bitumen roof installation ($976,000/20). Based off of yearly costs, the Alpha recoat was 100% more cost effective than a new traditional modified bitumen roof installation (table 6).

Results of Hail Tests 1 ¾ inch steel ball FM-SH test
The Casa View Elementary School roof was hail tested with ten drops of 1-3/4 inch steel ball from 17 feet 9 inches, which was equivalent to the industry standards of FM-SH hail tests on June 27, 2016. These hail tests were performed to determine the long-term performance of Neogard's Alpha roof system and the performance of Alpha contractors.
The Casa View Elementary roof passed in 9 of 10 drops. One drop ripped through the coating to reveal the foam. The other two drops ripped only to the top coat. During the 1 ¾ inch steel ball hail tests, the researchers found that only 1 out of 10 tests failed. On a 29 year old roof that was far past its warranty, the roof continued to show proven performance. Out of the 9 tests that passed, only 2 of those tests cracked to expose the top coat. All others had no damage or exposure to top coat or to the foam.

3-inch steel ball FM-SH test
Additionally, the researchers dropped a 3 inch diameter steel ball three times from the same height of 17 feet 9 inches. One of the steel ball drop damaged the coating to the SPF. The other two drops resulted in tears to the top coat. This far exceeds the FM SH test requirements. During the 3-inch steel ball hail tests, the researchers found that 1 out of 3 tests failed. On a 29-year-old roof that was far past its warranty, the roof continues to show proven performance. Due to the heavy impact, the ball caused the roof to crack to topcoat on the two tests that passed the test. The average width of the dent was very similar on all of the tests, averaging to about 88 mm. The average indent size was about 12 mm, due to the size of the ball being dropped.

Analysis of hail drop information
The results of the hail drop on the 29 year old Alpha roof not only prove that the Alpha roof system has FM-SH hail test performance, but it has outlived its warranty by 14 years. The level of performance far outlives a traditional modified bitumen roof due to the average repair and tear off of 20 years. The longevity of the roof has far outlasted the traditional modified bitumen with greater hail resistance as well.

Conclusion
Casa View roof system (61K SF roof area) was installed with a Neogard Permathane roof system in 1987. This means that the roof was 29 years old during the hail test (June 27, 2016). The Casa View Elementary School roof can be recoated to perform another 15 years for less than half of the cost of a modified bitumen system for a better value. Over the 40 year service life, the main difference of purchasing a 61,000 square feet Alpha SPF roof versus modified bitumen roof are savings of approximately $1,067,500. The existing 29 year SPF could not be differentiated from new SPF. In terms of base coating, the core sample near the site where the 3 inch diameter steel ball passed the FM-SH hail test had similar SPF thickness to the new SPF core sample.
The Casa View Elementary School roof was hail tested with ten drops of 1-3/4 inch steel ball from 17 feet 9 inches, which was equivalent to the standards of FM-SH industry hail tests. The Casa View Elementary roof passed in 9 of 10 drops. One drop ripped through the coating to reveal the foam. The other two drops ripped only to the top coat.
The researchers dropped the 3-inch diameter steel ball three times from the same height. One drop damaged the coating to the SPF. The other two drops resulted in tears to the top coat. This far exceeds the FM-SH test requirements.
A roof inspection was conducted and identified approximately 1% blisters and delamination and 9.8% recoated areas (around the edges of the roof). Alpha roof system is resistant to FM-SH damage (1-3/4 inch hail stone damage) within the warrantied 15 year time period. The authors advise that the Alpha system installed with proper slope and drainage improves performance, and will result in less repairs.