For a succesful installation of resilient floor coverings, whether they are glued down, floating, locking or loose-lay, a well prepared and checked floor is essential for the function and the visual appearance of the floor construction. The following points should be observed:
Subfloor should be completely clean, levelled, dry and free from impurities, durable, Tension and pressure resistant
Subfloors must be permanently dry: the residual moisture content of mineral subfloors should not exceed 2 % (or 1.8 % with underfloor heating); for anhydrite screed it should not exceed 0.5 % (or 0.3 % with underfloor heating). (test method: CM method, (www.cpm-radtke.com). On concrete subfloors consider the maximum humidity less than 75% RH when measured by a hygrometer/probe,
Moisture sensitive flooring systems (eg. Resilient floor coverings with MDF / HDF core) require a permanently dry surface. This can be ensured, in the case of mineral substrates, by using a moisture barrier (water vapor control layer) that protects the flooring from damage caused by rising damp. Moisture protection films can be either integrated into the underlay or be laid separately. The thickness of the water vapor control layer itself in this regard is of no significance, but rather its type and unevenness of more than 3-4 mm over the first metre of a run and ≥ 2 mm per every additional running metre must be compensated.