ᐅ Order of Screed and Plaster Work

Created on: 27 Apr 2016 15:18
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Christian123
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
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Christian123
28 Apr 2016 15:30
...a Bauder welded membrane with an aluminum layer. The plasterer inspected it on site and said that the plaster would not adhere to it anyway, so plastering will only be done up to the welded membrane (which extends about 4cm (1.5 inches) up the wall).
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Sebastian79
28 Apr 2016 15:33
I have S200 (or 400?) there – the plaster adheres to it.
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Christian123
28 Apr 2016 15:47
..OK. Then he should plaster over it. I’ll tell him that later.