Plasterboard in bathroom?

[Pimmsbec]

Hi there,
I'm having a bathroom remodel. It would be appreciated to get some expert advice.

Plumber ripped out existing bathroom and most of the metro tiles. He couldn't get the tiles off the main wall, adjoining the bedroom. He said they were affixed too strongly and removing them would damage the wall. For context, the wall is honeycomb partition. He hammered a huge hole in the tiles, in the centre of the wall and almost went through to the bedroom. His fix? Dab and daub a sheet of plasterboard over the top. It's almost like he gave up.
(This is the second time I've had my bathroom redone. The first time was 5 years ago, so the tiles aren't old. The previous plumber managed to get the tiles off, before putting these metro ones on.)

He has also used plasterboard and timber to build a stud wall which will house the concealed cistern and shower fittings. Previously, the bathroom had standard close coupled loo and exposed shower.

There are a number of issues with the work thus far:

1. The stud wall is not plumb, and it's very out. Needs remedying.
2. The plasterboard on the main wall results in the bath sitting proud of the recess, meaning it will over hang by almost 20mm.
3. The plasterboard worries me as it is normal, non-moisture resistant plasterboard.
4. He has built a cupboard, taking space from the adjoining cupboard in the spare bedroom (old airing cupboard). But the doors aren't plumb and when stud work is boarded and tiled, the right door won't open. Also, they're MDF doors - is this correct in a bathroom with no window?

Please can someone assess the attached photographs and offer any advice. Primarily on the use of standard plasterboard and failed removal of tiles.

Does the plasterboard need to come out? Gonna be a job to remove! But, a layer of old tiles, new plasterboard and new tiles takes up a lot of space, meaning bath doesn't fit without overhanging!

I've also attached a photograph of the bathroom before he began, so you can see that the bath sat flush in its recess, but now it'll sit proud.

Thanks and help!

 

[SimonG]

Have you asked them these questions?

 

[Pimmsbec]

Have you asked them these questions?

I have raised the issues regarding the stud work being out, and sticking plasterboard over the tiles and making the recess for the bath too shallow. But i've not asked about the plasterboard being the correct kind or not. I want to be sure I know what I'm talking about before I do - hence this post....

 

[Ben-gee]

There’s nothing wrong with using plasterboard, however in a wet area it should be tanked before tiling.

 

[Pimmsbec]

There’s nothing wrong with using plasterboard, however in a wet area it should be tanked before tiling.

What with? PVA or a proper tanking kit?

 

[Ben-gee]

PVA is not correct.
Tanking solution and tape for joints first.
In my opinion if the shower is not high pressure and you have large format tiles then acrylic primer is sufficient- but better to tank it properly.

 

[SimonG]

The only thing that worries me, after re reading, is the dot and dab over existing tiles on them crappy eggbox walls. The weight will exceed the loading on the original wall.
It may have been a chew but them tiles would have come off for me. If the wall was a mess then I would have overboarded with ply and then some no more ply to tile onto

 

[Ben-gee]

SimonG is talking sense. However from where you are I would suggest that if you add a few screws with decent (UNO) plugs into the original wall that will be fine.

Should always have a couple of screws at the top when dot/dab anyway - it stops what they call ‘peeling’

 

[Roy_66]

Sounds like wall is Paramount (about 35mm card egg boxes between two sheets of 9.5mm plasterboard). If orig tiles not well stuck on then you get away with one re tile, but after that ideally I'd scrap it. Assume if you build proper stud wall then you will lose a bit of space in the bedroom, although you could turn studs 90deg to make it skinny. If you really want to keep remains of the Paramount then I like Simon's idea of ply overboard. For the tile backing why not use a modern lightweight waterproof tiling board system.

That said I wasn't quite clear what kind of shower the wall had to stand up to.

Whatever don't use just plain plasterboard with no tanking. Cement board would last forever, but heavy and hard to cut.

It all depends how long you want it to last.

Other question is what does the wall stand on? Paramount is lightweight. If it doesn't sit on a wall below then having removed the paramount check what's under the floor. If wall parallel to joists but not near a joist then you may be best to noggin between the joists, and rest your new wall on the noggins (having first put the floor back).

So think I'd get a professional chippy in to check and sort it all out.

P.S. I'm thinking Paramount does not meet modern fire regs (anyone help me ?). So I'd be very careful if there are any electrics in the wall (Tricky but not impossible for original builders). Funniest thing I've seen is soldered plumbing in bott of Paramount walling. Again would not personally recommend.

Cheers,

Roy (very amateur plumber)

 

[exedon2]

Not fire regs that did for paramount N H B C sound transfer between rooms rules
Having said that metal studding often used on new build is not without its challenges when first fixing.

 

[Roy_66]

Not fire regs that did for paramount N H B C sound transfer between rooms rules
Having said that metal studding often used on new build is not without its challenges when first fixing.

Many thanks Exedon for clarifying that. I've only read one informal anecdotal report that said, unsurprisingly that it burned badly/quickly and I guess would never get approved these days, now we are somewhat more aware of these things. Removing the approval for it on the sound issue avoids complaints from existing customers on safety. Myself I think I'd have not approved it on grounds of maintainability, so no tiles, electrics, plumbing, as well as fire and sound. So very limited usefulness all round.

Living in a house with upstairs Paramount, I don't personally find sound transmission an issue. But I'm not lucky enough to ever have had kids playing loud "music" etc. LOL.

Cheers,

Roy