Plasterboard in a bathroom

proteus

Hello all,

I've recently renovated my house and have two bathrooms which I am tiling throughout. Both bathrooms are about 8' cubed with natural ventilation (window).

The problem is that the Builder used normal (grey) plasterboard in each bathroom and I have since heard that this can be problematic if it gets wet.
I have tiled one half of one bathroom and I'm so concerned about this potential problem that I don't want to continue until I know its solved.

According to posts on this board and other people I've talked to, the best practice is to use marine plywood around the shower and green moisture-resistant plasterboard elsewhere in the bathroom.

Since the bathrooms have already been studded (and partially tiled) this would not be easy.

Questions:
1/ How big is the threat of moisture damage using normal plasterboard?
2/ Is there a product I can treat the normal PB with to make it moisture-resistant? I heard of something called "Aquastop"?
3/ Is there any building regulations that state moisture-resistant PB MUST be used so that I have some leverage to get the Builder to replace the PB.

Thanks everybody

Barlow07

proteus wrote: »

Questions:
1/ How big is the threat of moisture damage using normal plasterboard?
2/ Is there a product I can treat the normal PB with to make it moisture-resistant? I heard of something called "Aquastop"?
3/ Is there any building regulations that state moisture-resistant PB MUST be used so that I have some leverage to get the Builder to replace the PB.

Thanks everybody

I would recommend skimming the plasterboard before you tile it or you could go to Chadwicks or the Grange and ask for some advice in there.

Reyman

Just a word of advice - my friend put up plasterboard in his bathroom. There was a small leak behind the bath that he didn't notice. The first warning he got was the tiles started coming off the plasterboard.

When he checked what was happening he found a leak behnd the bath the water had soaked up the plasterboard to 5 ft high. A week's hard work to sort it out !!

ircoha

proteus wrote: »

Hello all,

I've recently renovated my house and have two bathrooms which I am tiling throughout. Both bathrooms are about 8' cubed with natural ventilation (window).

The problem is that the Builder used normal (grey) plasterboard in each bathroom and I have since heard that this can be problematic if it gets wet.
I have tiled one half of one bathroom and I'm so concerned about this potential problem that I don't want to continue until I know its solved.

According to posts on this board and other people I've talked to, the best practice is to use marine plywood around the shower and green moisture-resistant plasterboard elsewhere in the bathroom.

Since the bathrooms have already been studded (and partially tiled) this would not be easy.

Questions:
1/ How big is the threat of moisture damage using normal plasterboard?
2/ Is there a product I can treat the normal PB with to make it moisture-resistant? I heard of something called "Aquastop"?
3/ Is there any building regulations that state moisture-resistant PB MUST be used so that I have some leverage to get the Builder to replace the PB.

Thanks everybody

AFAIK the 'Green stuff' has been discredited as a product, will look for ref and post it here

GreeBo

If your seal the bath/shower properly and tile/grout correctly you wont have a
problem.

If.

If you dont do any of this then even your WBP is going to be sitting in water, first thing you will know about a leak is when your ceiling below goes plop.

Autorotation

Hi Proteus,

I'm a total amateur at all this myself and trying to learn as I go but from reading tiling books (I recommend reading "Setting Tile"... very good) and gaining knowledge from tilers over the past while and the bits I've done myself there are a couple of things...

First, make sure the tiles you're putting up are not too heavy for the plasterboard. If they are marble or similar which are heavy they will eventually fall off, caused by disintegration of the plaster board.

Secondly, no tiles and grout are completely waterproof, no matter how well they are laid.

The plywood used doesn't have to be marine ply, which is quite expensive. WBP plywood is fine. The recommended way is to staple a sheet of waterproof membrane onto the studs, which should extend down beyond the waterproof strip on the shower tray or bath rim (it can be trimmed later). Then fix the plywood over this membrane, screwing (brass countersunk screws) every 300mm into the studs. Don't rest the ply directly on the shower / bath rim. Instead leave it 20mm high and fill the gap later with silicone. Incidentally most professional tilers won't even use plywood, they use cement backerboard which is similar but will never warp or be affected by moisture.

If I were you I'd stop tiling now, remove the tiles that are already up and then replace the plasterboard with wither WBP plywood or cement backerboard. Its easy enough and I think you'll save yourself major headaches in the long run. You only really need to do this around the areas that are going to get wet.

proteus

Autorotation wrote: »

I think you'll save yourself major headaches in the long run. You only really need to do this around the areas that are going to get wet.

Thanks for the replies all. I think I'll carry on and worry about the consequences later. If I have do do the repair work it'll be something I can do myself and I now know how to do it properly.:o