ᐅ Is it possible to plaster over expanding foam insulation, and if so, how?

Created on: 2 Sep 2021 06:23

Sorry for the possibly silly question, but is this possible? I often read online that it is, but there are no detailed explanations. For example, can you apply plaster directly onto the expanding foam (roughened surface, not smooth), or is it necessary to first apply a primer or some other bonding agent?

lesmue792 Sep 2021 10:11

In this recess, a sealing membrane was already installed by the house manufacturer. I’m not sure if this can be seen in the photos.

Exterior wall with rough plaster texture and rectangular opening to a dark interior.

Rough white plaster wall above dark asphalt floor; hole visible near floor area

Small square hole in dark asphalt next to rough white plaster wall; dark interior.

Exterior view: white rough wall with gap underneath; gray floor; red edge on the left; round metal ring on the right

BBaumeister3 Sep 2021 10:36

Phew, now I can picture it a bit better. It’s frustrating that it’s not plastered all the way to the bottom. The gap is too wide for an acrylic sealant, and any additional plastering would definitely be noticeable. To be honest, I’m not sure if expanding foam would even adhere properly to this bitumen waterproofing. Honestly, I wouldn’t trust myself to do it.

Is it possible to remove the stone slab again? That would certainly make plastering easier.

lesmue793 Sep 2021 17:57

I can’t remove the slab anymore since it was installed by truck with a crane/lifting hook. I’m now trying to patch it up or fix it with acrylic (I got a special acrylic with a coarse plaster texture). If it still looks bad later, my backup plan would be something like a stainless steel or tile baseboard.

ᐅ Is it possible to plaster over expanding foam insulation, and if so, how?

Reaktionen