Over the past several years, Barrett and her husband Sid have designed and built a beautiful rammed earth home in the San Luis Valley of southern Colorado. Located at an altitude of 7,600 feet in one of the highest alpine valleys in the world, Barrett's rammed earth home is entirely off-grid. It's 100 percent powered by solar panels. And, even though winter temperatures can plunge to 50 degrees below zero, an evacuated tube solar hot water collector system heats their hot water.

The thick thermal mass of the walls of the home, created entirely from the soil that they excavated on-site, protects the couple from the cold winter winds and the hot summer. In a recent interview with Rise, Barrett shared essential insights and advice related to how she and her husband designed and built a home constructed from locally-sourced materials.

What are some of the primary sustainability features? 

The house was built literally from the earth on site. That means very few materials were trucked into the site, and for those, we used as many locally sourced materials as we could find. The forms for the walls were plywood that, when removed from the walls, we used as our roof sheathing. We are completely off-grid. A well was dug before the beginning of construction, and a solar panel was installed to operate it. All of our power is solar energy; we are not grid-tied. We have a battery bank for electricity storage, and our heating comes from the sun. We installed an evacuated tube system for both domestic hot water and floor heating. The sun heats the liquid, which then flows into our storage tank and circulates through the home. We made our own clay wall finishes for the interior surfaces.

What proportion of cement was used to stabilize the walls? 

Approximately nine percent. We started at seven percent. But we found that due to the high sand content and lower clay content of our native soil, we needed to increase the amount of Portland to ensure stabilization slightly.