XPS allows effective, simple and quick insulation of concrete walls because they can withstand the constant humidity of the ground.
Polyisocyanurate is very effective in terms of thermal resistance. It is intended for the interior sides of foundation walls.
Medium-density spray-applied polyurethane is a very effective option but must be covered with gypsum boards.
In all cases, validation by a competent authority makes it possible to choose the right assembly according to the region where the building is located.