Maggie, Maguire Fellow in Dallas

Maggie I. is a graduate student studying design and innovation. She was awarded a Maguire and Irby Family Foundation Public Service Fellowship for summer 2017 from SMU’s Cary M. Maguire Center for Ethics and Public Responsibility. She is spending the summer learning more about compressed earth block technology, and designing modular building systems for rural communities.

Modeling and Exploring

The final stretch of my time as a Maguire fellow has brought about two critical stages of the design process: modeling and exploring applications.

For the past several weeks I’ve been working to create a small collection of models. Since the aim of my projects has been to make modular construction more accessible, the models needed to express the modules in their simplest form. They are commonly known as “massing models,” and essentially reduce a more complex shape into its most basic geometric volume.

In order to ensure the different modules could fit together, I created the first module to be just over 10’x10′ (well above the international standard for a bedroom). From that basic module I derived two more sizes, a half and a double (5’x10′ and 20’x10′, respectively). Since all the modules have at least two 10′ walls, they can be sequenced in any arrangement. Each house, then, could be comprised of any number and any type of module chosen by the family constructing it.

Though this design might seem straightforward enough, it didn’t come together overnight. The process can feel a bit slow at times, but I hope it can give you a glimpse into my former life as an architecture student.

It usually begins with a silly idea. A pattern, material, work of art, or building. In this case, it was the foam mats you probably haven’t seen since you were in kindergarten:

Just as we wanted the final product (a home) to be customizable, Adam and I also wanted the model to reflect that characteristic. A great way to accomplish that would be walls that could be removed and reconnected in different sequences. Luckily, I had actually done a study on interlocking, hinge-less boxes during my junior year of undergrad, but had learned that friction-based joints can be fairly temperamental. Adam thought of the foam mats, and I proceeded forward with the idea of toothed walls.

I began with a paper study. It’s important that early models take very little time to imagine and produce. It allows you to move quickly from idea to idea, learning as much as you can before committing to a design.

Next, I worked with chipboard to experiment with configurations.

Thanks to the DIG,I found an online tool that could make an exploded drawing of a box with teeth, as Adam had originally suggested.

After it produced the “standard” unit, I changed the size of the panels for the double and half rooms. I also removed most of the ceiling so the interior would be visible. The next step was to determine just how many teeth were needed to hold the model together.

While the box with only two teeth was faster to put together, the walls were far less sturdy. Since the models are meant to be played with and rearranged, I decided on the left option.

I made trials for all three sizes out of chipboard, and then transitioned to wood.

The final step was to introduce apertures (doors and windows).

Aside from model making, I’ve also been brainstorming different applications for the work that I’ve done over the summer. As I learned during CEB training at the beginning of the summer, there is still a lot of work to be done to standardize earthen construction, particularly here in the U.S.

Another research project at SMU is helping to do just that. Dr. Brett Story and his research assistant, Jase, have been working on structural and thermal tests for the blocks over the past year. I had the chance to meet with them last week, and learn more about the thermal standardization they’re hoping to achieve. We went out to the Dwell Earth training site, in Irving, to install some wireless temperature loggers. These little loggers will record the temperature every 10 minutes at five different locations on the site.

The first is the ambient temperature. You can see the logger hanging off the eaves. The second is within the shed itself.

The other three loggers are suspended within these three little structures:

The first is made of plywood, the second of concrete cinder blocks, the third of earth blocks. Over the next few months, Dr. Story and Jase will observe and record the internal temperature of the three small structures. This data will then be used as an integral component to the earth block’s standardization as a construction material.

I am so sad to see the end of my time as a Maguire Fellow come to an end, but thrilled to announce that I will be able to continue working alongside Dwell Earth, using much of what I learned through this project, during the academic year! As a fellow at the Hunt Institute, I will be part of a new project to bring an earthen village to the SMU Taos campus. I am hopeful that the project will help make earthen blocks more accessible to the general population, and help with the standardization of this amazing construction process.

Thanks for following along on this journey! If you have any questions or would like to continue the conversation, reach out to me at minhofe@smu.edu.

Posted in Maggie, Maguire Fellow in Dallas | Comments Off on Modeling and Exploring

V-Lock Blocks

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.

Posted in Maggie, Maguire Fellow in Dallas | Comments Off on V-Lock Blocks

DwellEarth Training Session

If I were to tell you that I spent the last week using a giant mixer, a piping bag and biscuit molds, you might think that I chose to redirect my Maguire grant to study the delightful field of baking. Rest assured, I’m still researching compressed earth block technology for a rural housing project. But I did get to use all of those things, and a lot of other seemingly kitchen-related material, out in the field when I attend DwellEarth’s training session last week.

I was one of 15 attendees at DwellEarth’s semi-annual training sessions.

DwellEarth is a construction firm that specializes in compressed earth block construction.

The other participants came from all over the world. Though earthen construction is certainly lagging in America more than in other parts of our world, I am happy to say that I had some fellow Texans in my company. We began the week with a brief orientation before heading out, almost immediately, into the construction site where the hands-on learning would begin.

The first day focused on material science. We learned how to identify the different components of soil to determine how viable it was for construction. These tests ranged from incredibly simple – involving nothing more than your hand and a sprinkle of water –  to more methodical – moving a mixture of soil and water through a series of test tubes to separate the different compounds.

Most soil is made of a mixture of clay, silt and sand. To prep the soil to be used in a compressed earth block, you need to know the proportion of these three components in the virgin soil, and see whether it needs any modification. Check out a few of my tests below!

One of the simplest tests. Simply mix a pile of soil with water until just moist. Rolling the soil into different shapes will give you different information about its properties.

Tools we used to test the soil. Beginning at the top left, you’ll see the soil mixes with 10%, 20%, 30% and 40% sand by volume, all jammed into biscuit molds. As the soil dried, some biscuits shrank or cracked, which helped us determine the correct amount of sand to add. My sample performed best in its original state.

This test determines whether or not the soil is expansive. After mixing with water and standing several hours, the sample should settle back below the black line. Our soil (on the right) was slightly expansive.

The second day focused on the block making process. Out at the training site were two different presses: one automatic and one manual. We began with the automatic machine. Based on our soil tests from the previous day, we put the appropriate amounts of soil and water into a mixer. We also added a small amount of cement to act as a stabilizer. After thoroughly mixing, the soil was moved up a conveyor and dumped into the press. The soil then funneled into the chamber to be subjected to a burst of about 2000 psi of pressure. Several seconds later, out popped a compressed earth block! The blocks were transported to a curing stack. The manual press worked similarly, but required a little more muscle to get the block fully compressed.

The BP714 (automatic press). The soil mixture travels up the steep conveyor into the hopper, and then is lowered into the chamber for compression. The levers to the left control the compression chamber, and the block is released onto another conveyor for inspection.

The Aurum (manual press). The soil is loaded into the top and lowered into the compression chamber. As the chamber lowers, the long pump (far left) is raised. Once the lid is locked in place, the pump is pulled down to compress then release the block. For most of our mixtures, It took two (sometimes three) teammates to complete the compression.

It amazed me throughout this entire process how intuitive these methodologies are. I began to understand how the dirt should feel before it went into the press. I could tell when it was too dry or needed more sand added in. The machines could speak to us, as well. Our instructor, Adam, encouraged us to think about the exercise as listening to the story of the block. The machine would tell us what we needed to know about the mixture, and we could adjust it in turn. Within a number of hours, our whole team – most of us with little to no experience in construction, let alone earthen construction – understood the fundamentals enough to begin producing quality earth blocks.

Days 3-5 forthcoming!

Posted in Maggie, Maguire Fellow in Dallas | Tagged , , , , | Comments Off on DwellEarth Training Session