Straightening and smoothing window reveals - any recommendations?

Hello everyone,

we are currently renovating our house into a KfW-55 house. The windows will be next soon. The old windows have already been dismantled. Larger chippings or recesses (old roller shutter box or belt winder) we roughly filled with cement mortar. Now we would like to smooth the window reveals nicely so that the window installer can install the windows with his Combri tape.

What is actually suitable to smooth the window reveals or to even out unevenness from 0 to 15/20mm? Thin-bed mortar? Lime-cement plaster? Some kind of filler?

I have to jump in here....what exactly did you fill the mortar with?

Personally, I would do the reveals only after the windows are in. At least that's how we did it here. First put in the windows with [Band] and then plaster, so you can make the [Band] disappear right away. For one window, we did it the other way around and then it was more difficult to cover the [Band] with filler. When is your interior plaster from? I did it with gypsum plaster or lime-cement plaster and filled it in, of course with external corner beads. I renewed the entire plaster right away, but for us, everything was falling off anyway and it was almost easier to just do everything at once.

I have to interject here... what exactly did you fill the mortar with?

For larger chips (deteriorations of the old windows) we used cement mortar. Sometimes there were also larger holes in the reveal because the house has pumice stones with hollow chambers inside. Such "larger" holes we filled with cement mortar. The window installer now says that the surface should be smooth because of his "compression tape and should not be so uneven." Therefore, the idea was to find out with what I can best smooth it out.

The plaster is probably from 1960. Of course, "corner beads" would be good for smoothing, but that would certainly increase the thickness of the interior wall (not the reveal). I would actually do the bead after the windows are installed. (or have it done)

Look up Laibungsglattstrich. It says for me that facade lightweight plaster is used for that.

Look up reveal skim coat.

We already discussed this here:

Take a look at Laibungsglattstrich. For me, it says that facade lightweight plaster is used for it.

Thanks, here I found "SG WeberKalkzement-Leichtputz IP 18E".


Thanks. I think one can also come to a conclusion in my thread. (Although this is not about whether one needs a smooth coat or not, but about what is ideally suitable here). But, as far as I can see, one shouldn’t make a science out of it. There are always different opinions from:

[*]Plaster & masonry mortar / cement mortar
[*]Lime-cement
[*]Construction adhesive / tile adhesive / styrofoam adhesive
[*]...

I will possibly take this lime-cement lightweight plaster :-) (Although it should be applied with at least 10mm, so you can’t apply it from 0-10 or 0-20, but have to build it up)