What residual screed moisture is permissible to ensure successful floor laying (gluing)?
The screed is usually made of cement or anhydride. Some floors may also contain underfloor heating. The residual moisture of a cement screed is 2.0% (for unheated) and 1.8% (for heated). The residual moisture of an anhydride screed is 0.5% (for unheated) and 0.3% (for heated). If there is any doubt about the level of residual moisture (e.g. in a new building), an accurate concrete moisture measurement must be made because excessive screed moisture would certainly damage a newly laid floor.
