What Is a Concrete Frost Wall?

Frost Wall

• Frost walls are large concrete structures built beneath homes to protect against damage caused by frost heave. Architects design frost walls to extend further into the soil than all the earth that freezes during a frost. The tops of these walls usually sit at ground level. Though frost walls can exist as a direct barrier between the earth and a building, they often exist within the design of a building. For instance, builders incorporate frost walls into the wall design of homes with basements in cold climates.

Frost Heave

• Frost heave is a natural phenomenon occurring in soil during freezes. When frost occurs, soil freezes. Any moisture in soil when a freeze occurs turns to ice. Ice possesses a larger surface area than the equivalent amount of water, meaning when moisture in soil freezes, it expands. Known as frost heave or frost action, this expansion can upset surfaces such as concrete. Frost heave can damage homes in numerous ways, and it can even lift them up and potentially detach them from their foundations in extreme cases.

Frost Line

• The frost line is the depth to which soil freezes. Frost lines vary from region to region. Local building departments keep track of frost lines, while some state governments list all frost lines throughout the state on their websites. Frost lines in Minnesota, for instance, run from about 50 inches below the surface of the earth to as deep as 80 inches. Anchoring a frost wall below the frost line with feet that extend from the corners of the wall ensures that frost heave exerts no effect on a building, because the lowest point of the house sits below the expansion point.

Developments in Frost Walls

• Frost walls evolved for the purpose of providing protection from frost heave. Building them from concrete ensures strength and durability, but offers minimal insulation from cold. Developments in frost wall technology seek to add a second functionality to frost walls by providing cold insulation. These developments incorporate materials such as fiberglass, protective panels, sealants and other forms of insulation into or onto concrete to increase a frost wall’s capacity to prevent exterior weather conditions from penetrating the wall and affecting the environment within a building.