A Somewhat Radical Idea

Sativa Building Systems started as an idea more than 5 years ago. Growing up the son of a builder and working in home construction myself for more than 7 summers gave me somewhat thorough knowledge of the building materials available. My father was a master of efficiency. He tweaked the building process to ensure homes could be constructed in the fastest way possible. He specifically focused his efforts on carpentry, but his knack for improving processes extended to all of the building trades. My interest always was more on the products themselves. I found the construction process to be somewhat tedious in some areas, mostly because of the products we used. I always wondered if better products of improved quality could make construction more efficient.

Green Building Products Intrigued Me

Flash forward a few years. After leaving the construction trades I still had an interest in home building. Through family and friends I started to learn more about alternative or green building products. I learned about cob, earthbag, strawbale, earthships, SIPS, adobe, etc. They all intrigued me, however each one had at least a minor deficiency. I knew that in order to truly breakthrough in a market and get widespread acceptance, an alternative product had to meet certain criteria. This is what I came up with:

  • It had to be more affordable than traditional construction. I did not want just a premium product. I wanted it to be accessible for all.
  • It had to be faster than traditional construction. I knew that no one would like for their home construction to take longer.
  • It had to allow for homes to look like a “normal” home. I understand that people typically like the look of traditionally constructed homes. To me, the idea of building an earthship (although they are cool) in a suburban neighborhood would just not be desired by most people. It looks weird.
  • It had to be a product that contributed to maximizing the health of the homeowners.

The last one is kind of interesting, but also one that is personal to me. When I moved into the home I currently live in we had somewhat of a rough first winter. My baby daughter at that time seemed to have lingering respiratory challenges most of the winter. She just seemed a little sick all of the time. One day I walked into our bedroom where she slept and I saw a little black staining where the carpet meets the wall below a window. This was odd to me, but I quickly found out it was mold. Ice damming on the window due to excessive indoor humidity blocked the weep holes on the windows and forced the water to back up into the walls. This trapped water caused mold build up inside of the wall cavity that eventually crept outside of the wall. In a weekend of tearing my bedroom apart I found the mold had spread to cover about 40 square feet of area. It dawned on me that homes are built in a way that attempts to keep moisture out, but also traps moisture once it gets in. This is a failed construction method.

Hempcrete Was The Answer…Almost

Hempcrete was the solution. Hempcrete met almost all of the criteria that I had set forth in finding or developing a more superior building product. If the hemp is sourced locally, it was affordable. It was breathable which meant that it IMPROVED indoor air quality and would not mold or rot. As a huge bonus, it was an environmentally friendly product. Hemepcrete, amazingly, is carbon negative. It did however have a few deficiencies. It could not be load bearing because if insufficient compressive strength. It takes 6-8 weeks to dry out before finishing. It has to be covered and protected while cast on site. Sourcing hydraulic lime which is believed to be necessary as a binder was expensive in the USA.

Hempcrete Really Was The Answer

Despite these challenges with hempcrete, I knew that this was the product I wanted to work with, and I was confident I could engineer around the inherent challenges that exist with working with hempcrete. A precast block or panel was the answer. I decided to develop a precast panel that would work symbiotically with traditional load bearing framing to eliminate the need for load bearing. A precast unit would also be ready to be finished upon being installed and would not have to be protected while it dried out, it was already dry. Lastly, I was confident that I could tweak a binder formula and source with more affordable and local products to keep costs down. This was the start of the journey, but truly just the start.

In the next post I will explain the development process and how the first prototypes were a complete failure.

-Zach Popp

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