Is Sod or Grass a Good Waterproofing Layer for Earth Homes?

Water Infiltration Risks

Using sod or grass as a waterproofing layer can lead to water infiltration into the earth home, compromising the structural integrity of the building. This is because sod and grass do not provide a sufficient water barrier, allowing moisture to pass through and potentially causing damage to the home’s foundation and walls. A 1-2 inch layer of sod or grass may not be enough to prevent water infiltration, especially in areas with heavy rainfall or high water tables.

Alternative Options

Instead of using sod or grass, earth home builders can consider alternative waterproofing options, such as applying a 1-2 mm thick layer of liquid-applied membrane or spray foam to the exterior of the home. These options can provide a more effective water barrier and prevent water infiltration. For example, Liquid-Applied Membrane (LAM) products are specifically designed for earth sheltered buildings and can provide a waterproof seal for up to 20 years.

Installation and Maintenance

When installing a waterproofing layer, it’s essential to ensure that the surface is properly prepared and that the material is applied according to the manufacturer’s instructions. Regular maintenance is also crucial to prevent water infiltration and extend the lifespan of the waterproofing layer. For example, inspecting the waterproofing layer for cracks or damage every 6-12 months and repairing or replacing it as needed can help prevent water infiltration and ensure the integrity of the earth home.