Frost Protected Shallow Foundations The foundation for a house is generally poured below the soil grade level so that the footing itself is well below the frost depth for any given region and soil type. This protects the house from frost heaving caused by expanding soils beneath the foundation. There are a number of situations, particularly with a slab on grade construction, where it would be useful to find a different way to prevent frost under a foundation. For this reason a lot of research has been undertaken and a number of building research institutes have gotten together to develop insulat...