Plaster gypsum walls

[Dr Benz]

What do I need to consider if I'm going to plaster the walls in the bathroom? The goal is to achieve a somewhat rough facade-like texture, not smooth like skim coating. What is the most suitable to use in this case?

Two walls are already painted, two are raw drywall.
Can you use gypsum plaster and float it to get that not completely smooth surface? Or should you use plaster mortar C?

Do you need primer on the painted drywall? Or maybe even on the raw boards?

 

[anders07]

You can apply plaster if it's interior walls. If you want a rougher surface, you can use a planed batten or a sawn plank for an even rougher surface.

 

[Dr Benz]

You can use gypsum plaster if it's interior walls. If you want a coarser surface, you can strike off with a planed batten or sawn plank if you want an even coarser surface.

Great. That sounds perfect.

Does the same apply if I'm going to plaster on brick later in the winter garden? Then, of course, use a primer first.

 

[anders07]

Great. That sounds fantastic.

Does the same apply if I will be plastering bricks later in the winter garden? Use primer first, of course.

Outdoors, or with risk of moisture, you can't use gypsum plaster.
There it's almost easier with a base coat, and then I think it's easiest with fiberglass mesh and a fiber plaster.

 

[Anonymiserad 405730]

Gypsum mortar will not resemble plastered finishes as it does not contain any coarse aggregate.

 

[Dr Benz]

Outdoors, or with the risk of humidity seeping in, one cannot use gypsum plaster.
There, it's almost easier with a base mortar, and then I find it easiest with fiberglass mesh and a fiber mortar.

No, it's indoors but external walls, so there might be a potential for moisture penetration, I suppose.

Suggestions for plaster then?
I was thinking of using Finja plaster C

Maybe I should do the same in the toilet instead? One of the walls is an external wall with aluminum paper as a moisture barrier/brake from the 60s. So I'm not sure how much it lets through.

 

[Dr Benz]

Gypsum mortar will not resemble plaster as it does not contain any coarser aggregate..

Hm. So is the risk that it will become too "smooth" perhaps?

 

[Anonymiserad 405730]

Hm. So the risk is then that it might become too "smooth" perhaps?

Yes, it won't be like a plastered surface since it's the sand (aggregate) that scratches the surface when you scrub or skim coat..
Visit a paint store, and you'll find paints/fillers specifically designed to mimic plastered surfaces..

 

[Dr Benz]

Yes, it won't be like a plastered surface because it's the sand (ballast) that tears the surface when you scrub or slurry..
Go into a paint shop and there are paints/fillers designed to mimic plastered surfaces..

Ok. So it wouldn't be a good solution to plaster with real plaster as I had planned to do on the brick in the winter garden?

 

[Anonymiserad 405730]

Ok. So it wouldn't be a good solution to plaster with real plaster as I intended to do on the brick in the winter garden?

Yes, regular plaster mortar B and C on the brick will be fine. It was the plaster I commented on that you don't get the same coarse structure as with plaster with sand in it, as these leave a coarser structure when you scour.

 

[Dr Benz]

Yes, regular plaster mortar B and C on bricks will work well. It was the gypsum mortar I commented on; you can't achieve the same coarse texture as with plaster mortar with sand in it since these leave a coarser structure when you finish them.

Exactly. And I also can't see that the gypsum mortar has any special ballast.

What I want to do now is also plaster the toilet (which is built from gypsum boards) to achieve the same Råå feel there.

But I can't find anywhere whether it is suitable to apply real plaster directly on gypsum.
Maybe with primer and base mortar, and then apply plaster C?

Everyone seems to advocate gypsum everywhere, but I don't think we'll be satisfied with that finish.

 

[Intet]

I've used sand-colored paint on drywall. Turned out really well, actually. But using rough paint in a bathroom where it might be good to be able to wash the walls thoroughly 🤔.

 

[Anonymiserad 405730]

Exactly. And I also can't see that the gipsbeuket has any special ballast.

What I wanted to do now was to also render the toilet (which is built of plasterboards) to get the same Råå feeling there.

But I can't find anywhere whether it is suitable with real plaster directly on plasterboard.
Maybe with primer and base coat and then on with plaster C?

Everyone seems to advocate plaster everywhere but I don't think we'll be happy with that finish.

It's too smooth it won't stick..
In that case you have to mesh and plaster if you want to plaster on the plasterboards..
I know a guy who is great at plastering with tile adhesive but don't know exactly how he does it..

 

[Dr Benz]

I've used sand paint on plasterboard. Turned out really well, actually. But to use rough paint in a toilet where it might be good to properly wash the walls 🤔.

Well, it might be foolish, but the idea is to put a marble slab like the floor behind the sink to catch most of it. But it does have a point, I think.

It might be better with gypsum plaster in the toilet and regular plaster on the brick in the winter garden.

 

[Dr Benz]

It's too smooth, it won't stick...
In that case, you'll need to net and plaster if you want to plaster on the drywall...
I know a guy who is great at plastering with tile adhesive, but I don't know exactly how he does it...

I understand.
I can't find anything that supports my wish either. I'll probably have to persuade the wife that it won't be the same for practical reasons as mentioned above.

I don't have the time/energy to experiment anymore; I need to finish the bathroom.

Thanks for the input.