As we reach the end of June, it’s amazing to think that summer is nearly halfway over! I have been working for the past few weeks on my design kit, playing with blueprints and scouring existing projects for inspiration. Wrapped up in the design phase, I completely forgot that I hadn’t shared the rest of my experience at DwellEarth training. While I’m sure that everyone was mesmerized in the science of soil, I thought it might be helpful to show you what that science can actually build.
We began with a dry stack. Dry stacking eliminates the use of an adhesive, and is made possible by the unique shape of the block.
As you can see in my quick sketch above, the block is shaped differently from a traditional brick. The raised area at the top of the block will nest within the recess of the block that is stacked on top of it. The v-lock technology of the DwellEarth blocks allows them to interlock without mortar. This means that structures can be completed incredibly quickly. We practiced our dry stack by making a small room, about the size of a tool shed. It took our team less than an hour to get the walls (mostly) built up.
In addition to the v-lock, the blocks have another component that makes them different from a traditional brick: two wide cores. The cores serve a few different purposes, both structural and aesthetic
On the structural side, they allow for a different type of lateral strength to be introduced. While the v-lock feature prevents micro movements between the bricks, the cores can accommodate rebar poles that add stability to an entire wall, and ground it to the site. As the crew lays the building foundation (usually concrete), they insert rebar along the perimeter, with three at each corner (as shown above). The cores can then be filled in with concrete, or left open. In high seismic areas, the rebar works with the v-lock system to provide extra stability to the structure.
The presence of two cores, instead of one that is central, also allows the blocks to take on the traditional, offset pattern of brick. The image below shows our dry stacked wall. The rebar, invisibly nested, passes through the cores down to the foundation below.
From dry stacking, we moved on to (surprise!) wet stacking. While the blocks can certainly be stacked using traditional adhesives, like concrete or mortar, we got to practice with slurry. The slurry mixture is very similar to that of the blocks (dirt, sand, and a little cement) but it is watered down until it resembles the consistency of runny mud. Or, for those of you who bake, a batter. This analogy is entirely more appropriate given we applied it with piping bags.
This image shows all of the unique components of this construction process at once. At the far end, you see the rebar protruding from what was once the empty core, now filled in with concrete for extra stability. Beneath, you can see the wood that marks the end of the foundation. On the blocks themselves, you can see the recess that gives the block its “v” shape, which will allow for the next block to sink and lock into place. Finally, you can see the slurry, and get an idea for its texture. Before this training, I never considered myself a dirt fanatic, but I can assure you that I now consider slurry my true medium.
After we practiced stacking, we talked about weatherproofing. Earth blocks are naturally fire, wind, and water resistant, but there are some additional measures you can take if you live in an extreme climate. One of these is to “seal” the blocks. While there are a few different brands and mixtures that can be found internationally, my favorite was the one we made: one part Elmer’s glue to five parts water. The sealant wash not only adds extra protection against the elements, it also smooths the texture of the wall. The first picture shows a stack that had not been treated, while the second shows our wall that had been washed and sealed.
Looking back on this week, I still can’t believe all that happened within such a short span of time. I was consistently amazed by the simplicity of the construction techniques we practiced, and surprised by the immense versatility of the ground that we walk upon every day. I loved hearing from my teammates about how earthen construction is already being used across the world, and, as I delve deeper into the design aspect of my Maguire grant, am excited to think about how those processes might be made more accessible.