The insulation of components in contact with the ground on their outside is called perimeter insulation, it is always outside the waterproofing of a building.
Particularly high demands are placed on perimeter insulation under floor slabs, as it is directly adjacent to the ground and has to bear part of the building's weight when used as load-bearing insulation. It is also exposed to moisture and chemical influences. Therefore, perimeter insulation is pressure-resistant, rot-resistant, and does not absorb moisture (or only to a small extent).
Due to increased requirements for thermal insulation due to the Energy Saving Ordinance, floor slabs are increasingly insulated underneath, even though according to DIN 4108 Supplement 2, constructions without external perimeter insulation under floor slabs are still permitted. However, a closed thermal envelope cannot be created with insulating boards inserted in the inner floor structure alone, so that a thermal bridge is inevitably created at the transition between the foundation and the outer wall:
Whether basement buildings or buildings without basements, the perimeter insulation under floor slabs ensures a closed thermal envelope and thus a structurally flawless Detailed training:
Source: bauwion
