Foundation slab insulation is a set of layers that protect the foundation structure against heat loss and moisture penetration from the ground. Its function is to reduce energy losses, improve indoor thermal comfort and protect structural elements against dampness and microbial corrosion (decomposition of building materials by micro-organisms such as bacteria and moulds).
In prefabricated and frame houses, the thermal insulation of the foundation slab is usually made of extruded polystyrene (XPS) or polyurethane foam (PUR). These materials are characterised by very low thermal conductivity and high compressive strength. The insulation layer is laid underneath the foundation slab and within its perimeter to form a tight thermal barrier.
In addition, a damp proofing membrane, heat-sealable membrane or bitumen membrane is used. The insulation protects the slab against capillary rise of water from the ground. Proper foundation slab insulation is crucial for the energy efficiency of the building and the durability of the entire structure.
