Lath and plaster repair (from behind!)

[Lobster]

I've just ended up pulling down all the laths and plaster off my old bathroom wall - plaster was blown and removing the tiles from the plaster was a non-starter. Now the wall on the opposite side of the stud partition, which faces on to the landing is also in a pretty bad state, blown in a lot of places. With the back of the wall now exposed you can see all the nibs of plaster extruded through the laths have broken off.

So before I put the plasterboard up in the bathroom I thought I might have a stab at some remedial work. Ideally the landing wall wants to come down too, but that ain't gonna happen any time soon! I thought I'd try chucking 1:4 PVA all over the back, and then essentially applying a very rough coat of Carlite bonding plaster to the back of the laths with a view to it holding the blown plaster. All that will be concealed as soon as the bathroom wall goes up.

It's got to be worth a go; has anyone tried this or got any refinements to suggest (eg which type of plaster)?

David

[Fitz]

refinements

I'm REALLY no expert but I'd probably brace the plaster onto the laths from the good side, to avoid any unfortunate pushing off incidents. Where I've had the same thing, the plaster was basically held up in one sheet, so pushing it off would be a bad thing.

[The Natural Philosopher]

I think you are spot on actually.

[fred]

I'd suggest using a smooth plaster to make it easier to spread and push into the little gaps & crevices more easily. I've only used browning + finish so don't know if bonding is smooth consistency or gritty. If it's gritty, then maybe use one-coat?

[Anna Kettle]

Yes I've done this but not on a wall, I have done it on a ceiling from above. Hoover the wall well before PVAing, propping the wall on the good side sounds sensible, on a ceiling you'd use a runny mix of gypsum and perlite which gets in holes easily and is lightweight but on a wall bonding might be just as successful - worth a try anyway

Would you let me know how you get on?

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Peter Parry]

This is what's recommended in an elderly book I have. Place a board on the good side and use a prop to press it against the plaster good side and then plaster from the back. It recommends leaving the prop in place for 24hrs .

[Mike]

I wouldn't bother. I bet once you've finished you'll wish you had just gone the plasterboard route as it will look better and have involved less work.

[Lobster]

How can it *possibly* involve less work? Read my original post.

Would you be happier if I said I'd promise not to use PVA?!

[BigWallop]

Plasterboard is cheap and easy, so don't faff about with trying to repair the old stuff. Rip it down and start again with new plasterboard. Leave the studs in of course. ;-)

[Mike]

I did. Throwing PVA and a bag of bonding coat at it will invariably cause more visible defects on the landing side which presumably will then need attention. Thus I still think you'll wish you hadn't bothered.

Hey, it's your project. I was just replying to your request for our thoughts. All are worth the paper they're not written on.

[John Miller]

I had the same problem on myu daughter's wall between bathroom and landing. Landing side was papered and that was all that was holding it together in places. I went the same route as you are proposing although I used Polyfilla on some of the critical bits near the door post. If it's well propped, you should achieve an acceptable result. My daughter was happy and that's all that mattered to me. At some time in future (when the wallpaper comes off?) it may need to be done properly, but it's holding OK for now. Go for it.

John Miller

[Rob Morley]

You might get away with just lagging it with PVA (so it runs between the lath and the plaster) then applying pressure from the other side (with boards and props as others have suggested) until it's thoroughly dry.

[Lobster]

Did the job at the weekend - TBH I delegated it to the plasterer I'd hired to do the whole bathroom. Hoovered the back of the affected wall, PVA'd it, then he slapped on a layer of bonding plaster. We had to cover the bathroom side with plasterboard before this plaster was solid and dry, so I can't really report back as to how well it's now stuck, but certainly the landing side seems very rigid now.

I decided against propping it from the landing side, because that side already had two thick layers of wallpaper which held the wall pretty flat anyway; and I thought that if there were any small gaps between the blown plaster and the laths then it would be better if some plaster got in there. The landing side is certainly still flat now, and there's much less of a hollow sound than before when you tap it.

Next time we decorate the landing I'll do the proper job with plasterboard, but I'm confident this bodge has staved off collapse of the wall for a good few years!

David

[The Natural Philosopher]

I've had bodges like that outlast the striuctures they were affixed to.

You will never need to touch it again.