The load-bearing substrate must be sufficiently dry and even (flatness tolerances in accordance with DIN 18202). Point-shaped elevations, laid pipelines, etc. must not lead to a reduction in the screed thickness or to structure-borne sound transmission through contact with the screed pane. Pipelines must be fixed to the subsoil and the layer must be levelled with suitable material, e.g. with pressure-resistant insulation materials or with fills whose usability has been proven. The height of this levelling layer must also be provided for in the planning. A continuous insulation layer, at least as thick as the impact sound insulation, must be arranged over the levelling layer. Pipelines must not interfere with this insulation layer at any point.
Waterproofing according to DIN 18195 must be made before the installation of the floating screed. Floating screeds must be produced in uniform thickness throughout, so a slope provided for in the screed surface must already be present in the subsoil.
Source: bauwion
