How do tire walls compare to conventional walls for insulation?

Earthship Tire Walls: A Sustainable Insulation Option

Earthship builders often use recycled tires as a primary building material for walls, which provides excellent insulation properties. Tire walls can be built by stacking tires and filling them with compacted dirt or gravel, creating a thermal mass that absorbs and releases heat slowly. This results in a natural, passive heating and cooling system that reduces the need for external heating and cooling sources.

Measuring the R-Value of Tire Walls

The R-value of a tire wall can be calculated by considering the thermal resistance of the tires, the soil or gravel infill, and the surrounding air space. A typical tire wall with 4 feet of thickness and 30-40 R-value can be broken down into its individual components: the tires themselves provide an R-value of around 10-15 per 4 feet, while the soil or gravel infill adds an additional 10-20 R-value per 4 feet. The surrounding air space contributes a minimal R-value of around 1-2 per 4 feet.

Building a Tire Wall: Tips and Techniques

To build an effective tire wall, it’s essential to use a combination of sturdy tires, compacted fill material, and a well-designed drainage system. A good starting point is to use 18-24 inch diameter tires, which provide a good balance between structural integrity and thermal mass. When stacking tires, it’s crucial to leave a 1-2 inch gap between each tire to allow for drainage and prevent water accumulation. Additionally, the fill material should be compacted firmly to prevent settling and maintain the wall’s structural integrity.