It is good practice to insulate concrete slabs in cold climates to protect the slab from frost penetration. There are a number of different factors at play but the one thing that we always need to keep in mind is heat flow. Heat flows from hot to cold, and in the wintertime, the ground temperature is warmer than the outside temperature the majority of the time. Keeping the heat flow principle in mind is the key to choosing the right approach to insulating the exterior concrete slab. If we know where the heat is, we can harness it and have a better chance of holding back the frost. The concrete slab insulation protects against the frost, but it’s because the rigid insulation is containing the heat the frost doesn’t penetrate.