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Climate Solution Building with HempWool: The Moontower Build with Cross Cabin Building Supply

Cross Cabin Building Supply founder, Greg Esparza, is on a personal mission in Austin to make homebuilding a part of the climate solution rather than part of the climate problem.

Greg Esparza is the Founder of Cross Cabin Building Supply and a Planning Director with Moontower Build. With his background in architecture and extensive experience in construction/business management, he was able to see many of the different aspects that go into building a home alongside the many people you build and plan with along the way.

Greg specializes in mass timber projects that are foam-free, vapor-open homes that prioritize a safe work environment for craftspeople, a healthy home for families, and a careful consideration of the climate impact of how building materials are made and how these materials can be recycled, reused, or naturally biodegraded in the future.

On Design and Building Development

Greg, who ran a Farmer's Market at one point in time and found himself inspired by the advice of journalist and author, Michael Paulin, quotes in his book, In Defense of Food:

Eat food. Not too much. Mostly plants”

But rather than food, Greg applied this to the built environment. Cross Cabin Building Supply was born from the experience of a case-study prototype project where Greg asked the question, “If we look at the process of building and designing a home and put the carbon and climate impact on the process of selecting materials first - what would happen with the design process? How would that steer the building process?”

After a fair amount of research on carbon-storing materials, Greg was ready to build with plant-based products like HempWool® vs conventional materials that are mineral or chemical based which take a significant amount of energy to extract out of the earth’s surface and manufacture into the materials we see often on construction sites.

For this project, Greg looked at carbon-sequestering materials such as:

  • Mass Timber

  • Cork

  • And Hemp

Having no experience building with these materials, he started researching and having conversations with folks who both manufacture and work with these products on his personal project, A-Cross Cabin.

What does it mean to build a house during a climate crisis?

Building a house during a climate crisis means more than just creating a beautiful living space. The decisions made during the design, estimating, and construction processes can have significant impacts on the environment. Homeowners and builders need to consider the carbon footprint of the materials used and prioritize eco-friendly choices.

Putting climate impact first

When designing a house, it's easy for the environmental impact of materials to fall through the cracks. To prevent this from happening, we need to prioritize the carbon footprint of the materials we use. By putting climate impact first, everything else can flow from there. We can still create spaces that feel really good while working with the logic and properties of eco-friendly materials.

The value of eco-friendly houses

Homeowners typically value houses based on countertops, finishes, and other aesthetic features. However, by prioritizing eco-friendly materials, we can tell a different story about the value of a house. Instead of focusing solely on aesthetics, we can emphasize the carbon footprint of the materials used. By using materials that store and lock carbon into building structures, we can create a different narrative about the value of a house.

Eco-friendly materials

To prioritize eco-friendly materials, we need to consider several factors. Firstly, we need to look at the depth of extraction for materials. The deeper we go into the earth, the more energy is required to extract the materials, which translates to a higher carbon footprint. Secondly, we need to consider how much carbon emissions are created during the processing of these materials. Thirdly, we need to focus on using bio-based plant materials that have a low environmental impact. By mimicking what nature has been doing for thousands of years, we can slowly drive carbon back into the earth's crust again. Real materials and minimal processing

The "food rules" concept also applies to building materials. Just like we should eat real food and rely on things that are not heavily processed, we should build with real materials. By using materials that require minimal processing, we can reduce the carbon footprint of the building. This approach to building can take many different forms, from using mass timber for structural components to using HempWool instead of spray foam insulation.

Building a house during a climate crisis means making eco-friendly choices and prioritizing the carbon footprint of the materials used. By putting climate impact first, we can create a different narrative about the value of a house. Using eco-friendly materials like bio-based plant materials, minimizing processing, and mimicking what nature has been doing for thousands of years are all ways to reduce the environmental impact of buildings. As we move towards a more sustainable future, it's essential that we make eco-friendly choices in all aspects of our lives, including building.

What inspired your sustainable building work?

Sustainable building practices have become increasingly important in recent years as we become more aware of the impact that our buildings have on the environment. The inspiration for these practices often comes from concerns about climate change, as well as a desire to create healthy work environments and reduce waste.

For Greg, the inspiration for sustainable building work came from seeing the negative impact of certain building materials on the environment. After reading about climate change and seeing graphics about its impact, he began to question why we continue to use materials like spray foam and hardy cement, which are derived from petroleum and have a high climate impact. Instead, Greg believed that bio-based materials, such as hemp and cork, could be used just as effectively if we knew how to work with them properly.

Another motivating factor for Greg was the desire to create a healthy and positive work environment for everyone on the job. Having worked in the industry for 21 years, he'd had seen firsthand how some materials could be harmful to personal health. As a result, Greg became determined to replace these materials with healthier alternatives that would be better for everyone involved.

In addition to concerns about personal health and the environment, another important factor in a sustainable building is reducing waste. Having worked on demolition projects Greg saw the number of materials that end up in landfills. He noted that many of these materials were not sustainable and caused problems in the long run. By using more sustainable materials and practices, we can reduce waste and create a more sustainable future for ourselves and future generations.

How was your experience working with HempWool?

"One of the things that were really cool you can see in the Cross-A Cabin Project is being able to have his carpentry crew put up the frame and put the HempWool in as they are building. This is not the traditional way that this process usually works but it was a really nice way to do this," Greg says, "it’s unusual to see framers doing carpentry work while also installing insulation at the same time."

Greg shared with us, "The crew really liked working with HempWool, it’s not itchy they were easy to work with, laid it out so they only had to make cuts on the last row, and then able to cover it all up and throw a metal roof on top. They really enjoyed working with the HempWool and in terms of the process, it was a really fast way to do the installation for having the carpentry crew install at the same time.

Additional thoughts and insights

The movement towards sustainability in building and construction is heading towards a more holistic approach, as evidenced by events such as the Hemp Building Summit and Mass Timber Conference. These events showcase the various aspects of building, including sourcing raw materials, craftsmanship, architecture, and building science, and how they can be integrated into sustainable building practices. The focus is not just on the technical design implications of the building but also on the sustainability and regenerative aspects of the materials used. The people, profit, and planet framework is often referenced in discussions about building with hemp and other plant-based materials.

There is also a shift towards thinking about building as an agricultural act, similar to the food movement, and being conscious of the materials used and their impact on the planet and craftspeople's health. The use of plant-based materials, such as hemp and mass timber, is becoming increasingly popular as a way to build better buildings while preserving traditional building practices. However, the construction industry is resistant to change due to the inherent risks and challenges associated with construction, and it may take time to convince contractors and subcontractors to use new materials such as HempWool.

One of the challenges in promoting sustainable building practices is the fixation on new technologies to solve problems when often the answer lies in traditional building practices that use plant-based materials. The craft of carpentry and working with natural building materials to construct houses have a long history in the US, and it is important to preserve and celebrate these traditions. However, there are also challenges in breaking through with newer materials such as HempWool, which may be more complicated to use and require lobbying and participation in energy coding conversations to become more favorable in the market.

In summary, the movement towards sustainability in building and construction is heading towards a more holistic approach that considers every aspect of the building, from sourcing materials to craftsmanship and architecture. The focus is on using plant-based materials such as hemp and mass timber, which can be regenerative and have less of an impact on the planet and craftspeople's health. However, there are challenges in promoting these materials and practices, and it may take time to convince the construction industry to adopt them. Ultimately, it is important to preserve traditional building practices while also exploring new sustainable materials and methods.


To learn more about Greg and his work with Cross Cabin Supply and Moontower check out the following:

Cross Cabin Building Supply

Cross Cabin Instagram

Moontower Austin

Moontower Instagram

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