Continuous insulation applied to the exterior of foundation walls reduces expansion and contraction concrete foundation walls would be subject to due to temperature differences between the interior heated space and the exterior air/soil.
Regardless of whether you have chosen a block or poured foundation, you will insulate the perimeter in the same method. The use of exterior foundation insulation reduces the likelihood of frost-heave under footings.
Insulating the exterior surface of the foundation wall provides the advantage of a fully insulated warm wall, which reduces the likelihood of degradation due to freeze thaw and of condensation forming on the inner face of the wall. (In other words moisture won’t drive through your concrete wall and appear on the inside.)
Insulating exterior foundations and perimeters is not just about code, it’s also about protecting the very thing your home is based upon, and increasing the interior comfort. Exterior insulation can be applied at the time of construction or added as a renovation project for increased efficiency and added energy cost savings.