Thermal Bridging in Earth Berm Structures — How to Avoid?

Minimizing Thermal Bridges

Thermal bridging occurs when a material with high thermal conductivity, such as metal, is in contact with the earth and the building, allowing heat to escape. In earth berm structures, thermal bridging can be minimized by using materials with high insulation values, such as polyethylene sheeting or foam board insulation, to cover the earth surface. A 1-inch thick layer of foam board insulation can reduce thermal bridging by up to 50%.

Insulation Layer Continuity

A continuous layer of insulation around the structure is crucial to prevent thermal bridging. This can be achieved by extending the insulation layer from the earth surface up the wall and along the roofline. A minimum of 2 inches of insulation is recommended for the earth berm section, and 4 inches or more is recommended for the wall and roof sections.

Material Selection

When selecting materials for the earth berm structure, choose materials with low thermal conductivity, such as wood or fiberglass, for the wall and roof sections. Avoid using metal or other conductive materials in contact with the earth and the building. Instead, use a durable, water-resistant material, such as polypropylene or a similar plastic sheeting, to cover the earth surface and prevent moisture intrusion.