Failed Prototypes and Pressing On

The process of developing the Z Panel was one of many unexpected twists and turns.  Initially I was going to call the company “Sativa Panel” because my first intention was build full 8 or 10 feet tall wall panels.  That didn’t work, and I will explain why, but first I will back up a little.

In creating a new hemprete product I set forth multiple criteria.  It had to be functional, that was my biggest priority.  What would be the point of creating a new product if it didn’t work well or was hard to install or was cumbersome to work with?  It also had to be superior to traditional products.  This one was somewhat easy because hempcrete by nature has many qualities that make it an inheritely superior building product.  I won’t go into detail on all of those, but being breathable, non-toxic, mold and rot resistant while have a high thermal value are some of the big ones.  Lastly, it had to meet a need that was not currently being met by current hempcrete products.  This meant that it had to be affordable and had to be something that could eventually be demonstrated to consistently meet building code standards.  Big goals, but attainable nonetheless.

The quest for affordability

In all of my research, I determined there was just one thing that made hempcrete more expensive than traditional construction. Every single material in hempcrete was expensive.  That’s it….. In all seriousness, nothing in hempcrete could be sourced cheaply.  Hemp shiv would have to be imported, meaning the bulk of the cost was just in shipping.  The most typical binder is a natural hydraulic lime or some form of hydraulic lime blend.  This is also typically imported making it expensive. I set out on a quest to get comparable or even the same materials more locally, or at least in the United Sates. 

The problem of getting hemp locally is resolving itself thanks to laws now allowing for the local cultivation of hemp.  This will continue to be a huge for us.  The challenge of finding a replacement to European sourced hydraulic lime was a bigger obstacle.  I spent countless hours scouring the internet and digging through research to land on the most viable option.  I even consulted with some friends to the north in Canada who have experimented with different binders.  I determined that with potentially the right additive, I could make much more affordable and locally sourced HYDRATED lime act like Hydraulic lime.  However I needed to test this.

Test block panels with sections cut out to test integrity

A recipe for success

I made a small 1’x1’x1’ cube mold to pour test hempcrete mixes into.  Then I bought every hempcrete binder on the market.  Then I bought multiple different additives or pozzolans. My garage turned into what looked like a mad scientist’s garage.  Nearly every night for several weeks I would go into my garage and mix up a new batch of hempcrete with different ratios of hemp:lime:water.  I would also swap out the binders.  I even bought some of the most expensive European binders to benchmark against.  I eventually had a few dozen small hempcrete blocks in my garage.  Then…. I examined them all.  I examined how or if they crumbled.  I examined how well they dried.  I applied weight to each one to test their compressive strength.  I even surprised myself with how thorough I was, it was painstaking. However it was worth it.  I made what I believe a pretty substantial discover.  I made a block that appeared to be just as strong as the most expensive block with the European binder.  However, I simply used hydrated lime sourced about an hour from where I live, along with an additive also sourced in the US. That additive is my secret.  I was onto to something big. This “recipe” was not only proprietary, it worked.

The next phase was to take the formula or recipe I created and pour the hempcrete mix into the molds for the full 8 foot panels that I planned to manufacture.  I also knew that I would want to speed up the drying time as much as possible.  So, I built some molds that that were essentially encased in a wind tunnel.  This look a lot of time and some makeshift rigging, but I made something work.  My goal was to reduce the drying/curing time from what would normally be 6-8 weeks down to a few days.

I patiently waited several days and tested the moisture content with a probe daily to see how dry the test panel was.  The outside dried faster than the inside, which I expected, but the difference was significant.  After about 4 days of drying the first few inches of the panel were sufficiently hard.  I decided to attempt to tip up and maneuver the panel.  According to my calculations it weighed over 200 lbs, and it definitely felt that way as well.  As I began to tip up the panel it started to fall apart, not totally, but enough that the integrity of the panel was obviously compromised.  The interior of the panel was just not dry and hard enough to keep the panel from crumbling under its own weight when it went from a horizontal to a vertical position.

Over the next weeks I modified the drying tunnel and casted a new panel.  Same result…. The idea of casting an 8 foot panel that was 16 inches wide and a foot thick was just not working.  I was incredibly discouraged.  It appeared my idea was failing.  Then it dawned on me that even if these large panels retained their structural integrity, they were very large and heavy and definitely could not be set safely by one or even two people. I needed to do something different, but yet build off of the successes I had already.

From panels to block panels

I realized if I really just cut my 8 foot panels down into 2 foot sections I would have something that not only would dry out faster, but would be easier to lift and set in place by one person.  This made sense.  I had a solid idea.  Basically I cut my mold down from being 8 feet long to just 2 feet.  Then I positioned inserts inside of the mold to create the recesses so these smaller block panels could interlock with each other and the structural framing.  THIS WORKED! I decided then to manufacture a few test block panels and cut into them to see if they maintained their integrity or shape.  They did. 

The next year was basically dedicated to creating multiple molds and then doing an initial production run of blocks to supply the materials for the greenhouse build. With every block that I successfully made I felt like my ideas and design were being validated.  Manufacturing blocks by myself in my 400 square foot garage was definitely challenging, but necessary.

Z Panels drying

Now I can say confidently that I created something that isn’t just novel, but also functional, and possibly game-changing for the construction industry.  I am leaving out a lot of details, like the patent application, and many manufacturing modifications made along the way.  I also at one point built a 4 foot mock up wall and tested various finish coats.  This has been a journey

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