Tiling On Damp Plaster??

[johnk]

I'm trying to seal around the top of my bath because of a leak when using the shower. I cut all the sealant away and found the grout was loose on the bottom row of tiles. I removed the grout and found the tiles were loose so I removed them. I want to stick them back again but the plaster they came off is damp so do I have to wait until the plaster dries?

[ummmm]

Yes. You'll need to see what state the plaster is in which you won't know until it dries.

We had a leak upstairs. Let the plaster dry but if you touched it it crumbled.

[woofgang]

I agree with Ummm, also when you re seal, fill the bath with hot water. If you seal an empty bath, the weight of the water can distort the bath and pull it off the silicone, also by using hot water, you will soften the bath and thus distort it as far as it will go. Once the bath is cool and empty, it will return to shape and squeeze up the silicone but it won’t stretch and distort the silicone when you use the bath. If its a shower use leak and you can, it can help with the drying out process to take the side panel off the bath to key the air get round.

[johnk]

I've got the side panel off with the window open, seems to be taking it's time to dry though.

[ummmm]

How old is the house?

[woofgang]

hairdryer?

[johnk]

The house is about 45 years old
I'll try the hairdryer if it doesn't dry by tomorrow I just don't want it to be top dry and still damp underneath.

[woofgang]

top dry it with the hairdryer then leave it and see if the surface becomes damp again.....be patient!

[The Builder]

It might take some time John. If it's been showered on, then the whole wall is probably just as damp. As you dry the exposed area, it will keep taking more damp from the wet areas.

Plaster is not the best surface for tiling. Ideally, tiles should be applied to unplastered backer board such as "Hardiebacker", or water resistant plasterboard.

I doubt if you'll want to take off the tiles and fix new board, so I'm afraid it's just a matter of keeping an eye on it until it dries out. If you want to push it on a bit, then coat the plaster with PVA before re-tiling. The PVA will soak into the plaster and re-constitute it.

[johnk]

Builder, thanks, it seems to be drying out a bit. I think just the lowest row got wet behind the tiles because the grout was loose, everywhere else seems OK and the tiles go up to the ceiling so I don't fancy ripping them all off. I'll use some PVA like you suggested and if I do any more tiling I'll remember the backer board. Thanks for you help.