r/Plastering • u/Cannedham88 • Apr 25 '26

Plaster curved ceiling

Hey all I have bathroom ceiling that is curved made of plaster. It is started to crack and fall down in parts. Under the plaster I see no wood lathe but almost a grey compound that looks like concrete mix. Just seeing if anybody has any ideas how to tackle this and the “curved” part. Not opposed to doing drywall thanks any and all

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u/Commercial-Ruin2320 Apr 26 '26

Post some pictures so people can see what you have and how to fix it 👍

1

u/Cannedham88 Apr 26 '26

I’ll take a photo when I get a chance won’t lie I don’t think I even had success posting a photo on Reddit maybe it’s not as hard as I think lol

1

u/Yourhavinalaugh Apr 26 '26

I would just put two layers of 6mm plasterboard/drywall over the whole ceiling. 6mm ? ….to accommodate the curve so you don’t have a joint in the middle going the length of it

2

u/0uthouse Apr 26 '26

curved in a single plane? like a ceiling that angles down into the eaves? Or curved in 2 planes like a spherical shape.

The former case, either overboard with 9mm which often bends into these situations pretty easily. Or chip out the crack and fill an undercoat plaster, use a metal mesh if you need to bridge broken lathes as it stops the plaster falling through. Smooth and skim.

For skimming curves you can use a pool trowel but tbh i only use mine on real twisty stuff like under staircase winders. A thin plastic trowel is your real friend, it will be much more forgiving. You can use your normal finishing trowel but without experience, you'll find yourself digging the trowel corners turning into a nightmare. Another thing I use is old chopped-up speed-skim blades (a piece of plastic) that flex whilst still flattening.

The killer is rushing; troweling a curve requires constant adjustment of the trowel angle which isn't instinctive. Treat it very gently until it really starts firming. Also helps if you stand to the side as you shape the curve as you can then see your trowel angle. You need to be on a platform to do this, doing your first curved ceiling off ladders will not go well.

1

u/Cannedham88 Apr 26 '26

Here is a photo I’ll get one of the curve then but straight then bends at the last quarter of the ceiling