Fachverband Holzpflaster e.V. | Rethelstraße 28 Hof | 40237 Duesseldorf | Germany

Minimum Sub Floor Requirements GE

The undersurface must be ready for laying in accordance with DIN 18367 “Woodblock work” No. 2.1.2. Bonded screed (“Screed mortar”) CT - C
35 F 5 to DIN/EN 13813 and/or concrete B 25 to DIN 1045 must be used. An essential requirement for the suitability of the undersurface for woodblock is its correct composition, production and installation. The constituents must not become separated. It must be completely sealed
and capable of supporting the load, and carefully treated. (See also the new edition of DIN 18560 “Screeds in construction work” (2004/4))

The surface of the concrete or screed must be rubbed down to accept the woodblock, but not completely smoothed. It must not release sand or dust. Subsequent treatment is essential in accordance with the “Guideline on after-treatment of concrete”, e.g. by the laying of film sheets or similar.


The envisaged after-treatment is also intended to ensure that the surface remains sufficiently firm, and that no gaps occur during the usual grid-gap testing. (Surface adhesion strength = at least 1.5 N/mm²). If the envisaged use requires higher values, these must be agreed separately.


The levelness tolerances must at least comply with the value specified in line 3 of Table 3 of DIN 18202 (May 86 Issue). Rising damp from the undersurface The same requirements and measures apply here as specified with regard to this subject on Page 6 damp from the undersurface can cause serious damage to woodblock floorings laid over such surfaces. In the case of bonded screeds and concrete, the surface must be protected against rising damp, e.g. by sealing.

©2011 Fachverband Holzpflaster e.V.