ᐅ Silicate paint on walls, emulsion paint on ceiling, color differences?

Hello everyone,

we are planning to start the painting work soon. The walls have gypsum plaster which was subsequently skim-coated. The concrete ceilings will be covered with painter’s fleece wallpaper.

We would have preferred to use silicate dispersion paint for everything. However, since wallpaper should not be painted with silicate paint, as the mineral-based paint cannot properly bond to it, only dispersion paint is suitable for the ceilings. We wondered if it might be possible to order dispersion paint and silicate dispersion paint in the same color tone from the same manufacturer and paint the ceilings with the dispersion paint and the walls with the silicate paint. Or would it be better to use only dispersion paint everywhere to avoid any color differences?

Silicate dispersion paints can sometimes be applied on wallpaper. A well-known manufacturer starting with S offers a specific paint that is explicitly marketed for this purpose, so we will probably use that for everything.

Why use silicate paint, which is generally not intended for gypsum-based surfaces (and if at all, only with special primers)? It is primarily designed for mineral substrates. There is no silicification with gypsum, and without a special primer, it can even damage the gypsum.

It offers exactly zero advantages for this type of substrate.

Please don’t get upset if you are not completely satisfied with the result. Consider this your warning.

KarstenausNRW schrieb:

Why use a silicate paint that is generally not intended for gypsum or similar surfaces (and if at all, only with special primers)? It is actually designed for mineral-based substrates. There is no silification process on gypsum, and without a special primer, it can even damage the gypsum.
It offers zero advantages on that type of substrate.

Please don’t be upset if you’re not quite satisfied with the result. This is a warning for you.

Okay, I wasn’t aware of that; I thought gypsum was mineral-based, so I assumed the opposite was true. Then we’ll probably go for a dispersion paint.

Of course, you can use dispersion silicate paint. The 5% dispersion ensures it adheres even without silicification.
The advantage of no silicification is the high alkalinity, which reduces susceptibility to mold compared to dispersion paints, makes application easier, and in my opinion, also provides better results compared to lime paint.
So in conclusion: you can use dispersion silicate paint for your walls and ceiling.
No special primer is needed.
I painted my ground floor like this, including both painter’s fleece and gypsum plaster. The paint does not peel off anywhere.

Tolentino schrieb:

Of course, you can use dispersion silicate paint. The 5% dispersion ensures that it adheres even without silification.

Then I might as well skip the mineral paint altogether. Without silification, the alkaline effect fades quite quickly.

Tolentino schrieb:

I painted my ground floor like this, using both painter’s fleece and gypsum plaster. The paint has not peeled off anywhere.

Then look forward to when you want to repaint. And remember this thread in a few years ;-)

Tolentino schrieb:

No special primer with magical adhesive properties is needed.

And please don’t complain if it doesn’t go well, because then you’ll have to ask yourself why you didn’t follow the manufacturer’s instructions. They explicitly require the special primer for dispersion silicate paints. Sto has its reasons.

KarstenausNRW schrieb:

Then I might as well skip the mineral paint altogether. Because without silicification, the alkaline effect fades quite quickly.

How should that work? Indoors? Do the silicates then gradually wash away with baby vomit and the saliva of complaining partners, or what?

KarstenausNRW schrieb:

Then just look forward to repainting someday. And remember this thread in a few years ;-)

I will, promise—if this forum still exists by then.

KarstenausNRW schrieb:

And please don’t complain if it doesn’t work well, because then you’ll have to answer why you didn’t follow the manufacturer’s instructions. They explicitly specify the special primer for silicate dispersion paints. Sto knows why.

I won’t complain—or at most with the manufacturer of my paint. Because I have followed their instructions.

I checked Sto for fun. For Sto Sil In, there is no mention of a primer in the technical datasheet. It even lists textured wallpaper as a possible substrate.
For absorbent surfaces, primers (nothing magically adhesive) are recommended. Of course from Sto, but chemically nothing special.

Normally, I appreciate you and your posts a lot, but here you’re giving credence to fear-mongering tradespeople who want to turn their craft into some kind of magical secret knowledge, like a medieval guild.

Yes, the very durable effect of silicification is missing on gypsum or wallpaper substrates. But you can still paint over them with a dispersion silicate paint because the dispersion binder ensures the paint adheres to the substrate. The silicates are still present and are alkaline before silicification anyway, so the mold-inhibiting benefit remains.

By the way, silicification can also be a disadvantage if you want to remove the paint for whatever reason later. Then you have to sand down thoroughly several millimeters (mm). Granted, you’d have to be quite inventive to create such a situation, because pure silicate paints can be overpainted later with any paint, so there should be no real reason to sand off the old paint first. But I just wanted to mention it.