ᐅ Order of Screed and Plaster Work

Hello everyone,

Normally, the sequence is first the interior plaster, then the screed. However, since our floor slab (made of Poroton clay blocks) is insulated on the inside with 16cm PUR (6.3 inches), I would like to change the order... specifically, starting from the floor slab: vapor barrier, 10cm PUR (3.9 inches) continuous insulation, installation of empty conduits for electrical, ventilation, and plumbing, fitting the remaining 6cm PUR (2.4 inches) with subsequent perlite backfill around the pipes, Rolljet, underfloor heating, screed, and only then applying the plaster up to the screed (for sound decoupling, I would use an edge insulation strip underneath).

Lately, I have read repeatedly that the plaster must be applied all the way down to the floor slab for airtightness reasons... is that really necessary? Or can this be solved differently?

Best regards,
Christian

Interior insulation is not unusual. Nevertheless, apply the plaster first and then the rest.
You also don’t want to have all the dirt on the screed.

Hello Christian,
The standard procedure in residential construction is indeed to apply the wall plaster first and then the screed.
However, it is obviously possible to do it differently!
The main thing is to ensure that wall surfaces and the screed do not form a rigid connection (due to sound insulation).
The plasterer must then provide a decoupling layer between the wall surface to be plastered and the screed surface.
They will typically install a strip below the bottom edge of the plaster.
Higher costs will arise when grinding the screed before installing the floor covering.
This is because mortar spots on the screed, which are unavoidable during plastering work, must be removed.
The plasterer can do this at their own expense (if they do not want to cover the screed surface) or the floor installer can handle it as a paid main service.
This has nothing to do with a “cleaning grind” (an additional service by the floor installer)!
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Best regards, KlaRa

What advantages do you see in the order of screed/plaster compared to plaster/screed?
We also insulated on the base floor and had the plaster/screed order...

xray107 schrieb:
What advantages do you see in the order of screed/plaster compared to plaster/screed?

None.

Baseboards can be installed flush with the wall quite easily, as you can place something directly on the screed. Doing it the other way around is always more difficult, because the screed will never be exactly the same height everywhere...