re-plastering over brick: getting a good finish

[fatfewl]

Hello,



I am seeking advice on re-plastering over brick.



I’ve just started some pretty serious renovation work on a property and have stripped back from plaster to uncover some wires in readiness some re-wiring. That is a different topic but my question is what type of plaster is this? It is directly applied to an inner brick wall. This is a Georgian period property but I don’t know if this is the original plaster work. It has a strange smell, almost like stale cigarette smoke and is very dry and crumbly. It also has some hairs in it make me think it might be the original plaster or else at least quite old. I could see that the plaster that that been applied over the cables was a different more modern plaster.

All the walls in every room (with the exception of two more modern walls) is brick covered with this same plaster – and then the same textured wall paper over the top. I want to get rid of all the textured wall paper and replace with a smooth plaster coat that will be directly painted.




I could try carefully removing the textured wall paper as the surface underneath is fairly flat. However it would need to be further prepared and sanded if paint is to be directly applied over the top.



The second option would be remove all the plaster and strip it back to the brick. A messy, tedious task but the plaster comes always very easy.



The last option would be to apply a very thin layer of plaster over the top of the old plaster once the wall paper is stripped? I think I would rather not do this as it would increase the wall thickness. The currently plaster later is about 23mm thick.



What’s this under the textured wall paper? Older wall paper I assume?

I guess ultimately my questions is the best strategy to getting a decent smooth and more modern finish? Any general advice or tips would be greatly appreciated. Thank you.

 

[cdbe]

If the plaster can be easily removed from the wall it has failed and needs replacing with either sand/cement render, bonding plaster or plasterboard dabbed (stuck with adhesive) onto the bare brick. In all cases it would be finished with a final skim coat of multifinish. If the plaster is well adhered to the walls then you might get away with just a skim coat.

 

[Mike13]

The powdery hair filled stuff is a lime plaster as opposed to a gypsum based modern plaster. Harder to apply and also hard to obtain fresh enough lime to make it. But it does give a better control of humidity in the room, it doesnt crack so easily as it flows with the bricks.Also, you cannot use polyfilla on a lime plaster wall, as it does not stick to the lime, the pollyfilla moves when you paper it etc...
Gypsum plaster hardens quicker, much more available, but being more brittle it tends to crack at the corners.

https://www.lime.org.uk/products/lime.html