Heat cement screed according to plan

Floor underfloor heating systems are usually used to construct a leveling screed; the standard is calcium sulfate as a binder. CA-screed, in combination with underfloor heating systems, clearly has the best heat transfer and storage properties and therefore ensures the best possible heat transfer. Nevertheless, a heating screed can certainly be a conventional cement screed. After an initial drying phase, the screed with the underfloor heating must be heated and cooled again according to a well-defined plan. Even for cement screed as a heating screed, there is such a plan, but must be modified according to the constructed layer thickness or under special conditions accordingly. The following standard heating plan applies to layer thicknesses of up to 70 mm in total and average, unproblematic temperature conditions

The standard heating plan for dry screed

The initial drying phase lasts 21 days, during which time the floor heating must not be used. During the first five days after installation, the screed should additionally be kept moist in order to avoid later cracks.
From the 21st day the heating is operated with a flow temperature of 25° C, the night reduction remains switched off. This temperature is maintained for three days, after which it is increased by 5° C per day up to the maximum temperature of 55° C. Higher flow temperatures should generally not be used for heated screeds. The maximum flow temperature is maintained for three days, then slowly lowered again by 10° C per day. A subsequent residual moisture measurement should show a ready-to-use screed. In any case, a three-day cooling-down phase should be carried out before covering, in order to slowly bring the entire screed back to room temperature.

Use of rapid heaters or building drying methods

Experienced professionals can also use quick drying to shorten the first 21 days. But this can be risky depending on the structural conditions and should really only be made by experienced screed layers, otherwise severe damage to the screed threaten.

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