Staalmat
Vloerverwarming gebonden aan staalmatten onder een dekvloer
For a concrete subfloor with no screed yet in place, the underfloor heating pipes are bound to steel mesh.
The screed usually consists of a 5–7 cm layer of sand-cement or anhydrite. The mass of the floor acts as a heat battery — unlike milled-in heating, it takes longer for the heat to be released, but also longer to cool down. This is favourable because the heat source cycles on and off far less often.
With less than 5 cm of space for the screed, only steel mesh is used and the sand-cement bonds directly to the structural floor. With more space, the screed can be laid as a floating floor. Edge insulation then limits sound transfer to the walls, and reflective foil ensures even distribution of the heat.
Reflective foil has earned itself a questionable reputation — air is needed between the heating element and the foil for any reflective effect to occur. To prevent heat loss downwards, insulation from below is needed. Aim for floor insulation of at least R=3.5 or higher. Can the subfloor not be insulated from below? Then tacker or stud plates offer a solution between the subfloor and the top layer.
After the installation is complete, a third party can pour the sand-cement or anhydrite. The underfloor heating unfortunately cannot be switched on right away — per centimetre of screed, a drying time of one week applies. So 6 cm of screed means 6 weeks of waiting.
