ᐅ Glue-based paint – what it is and whether it must be removed

The two photos show the current condition of the ceiling. It is supposed to be white glue paint, which must be completely removed before applying the primer, according to the explanation from the paint specialist I trust.

The photos show scratched plaster; the indentations naturally need to be filled with a filler.

Also visible are two different white surfaces:

- The already scraped-off area is directly on the plaster and smudges heavily when rubbed by hand.

- The raised white surface is the white glue paint, which has already been sanded with a drywall sander (known as a "Giraffe"), but could not be completely removed (the 60-grit sandpaper smeared, as did the sander’s air filter when used too frequently), so now the white glue paint is to be scraped off.

The workers on site have different opinions:

1. Scrape off the white glue paint, then remove the remaining white layer down to the plaster with the drywall sander, then apply the primer.

or

2. Scrape off the white glue paint, apply primer on the remaining white layer, because it is not white glue paint but filler.

My feeling is that everything white belongs to the white glue paint and must be removed—why would there be so much filler on the plaster?

Dear all-knowing forum, please help me to reach a final opinion.

I think the white layer under the paint is actually gypsum filler, something like Knauf Rotband or similar. It could stay, it just needs to be stabilized with a primer before painting.

By the way, why didn’t you just paint over it with glue-based paint? That works, after all.

Nordlys schrieb:

By the way, why didn’t you just paint over it with glue-based paint? That should work.

Unfortunately, you’re asking the right questions 😡 😉

I had read once that glue-based paint can deteriorate, but it probably would have been the sensible choice.

Nordlys schrieb:

I believe the white layer beneath the paint is actually gypsum filler, something like Knauf Rotband or similar. It can remain but should be primed with a suitable primer before painting.

If it really is gypsum filler, how can I tell where the glue-based paint ends and the gypsum filler begins, or when enough filler has been applied...?

Ultimately, not at all. Only if there are still some remnants of paint on the fully scraped and sanded surface, this will not affect repainting. You can assume that whatever remains will adhere well, and the new paint will be able to stick to it.

Nordlys schrieb:

Ultimately, not at all. Only if there are still remnants of paint on the fully scraped and sanded surface, does that not jeopardize repainting. You can assume that whatever remains will adhere well, and the new paint will be able to stick to it.

Uncertainty makes me nervous 😕

The specialist dealer was insistent that the distemper paint must be removed. Anyway, tomorrow a tradesman will apply an expensive remover to dissolve the paint—I hope it takes off all the distemper.

I might be able to convince the tradesman (all-rounder/renovator – comes from the construction field) to use a giraffe sander as well.