Bathroom: Our installer used standard plasterboard - is that ok?

[John__]

Hello all,

Our bathroom fitters have finished the first fix.

However, when the tiler came round, he pointed out these issues:

1. Standard plasterboard has been used throughout (including the future shower area), rather than using the waterproof variety of plasterboard or to use tiling board.
2. The bath is not sufficiently level: Either there will be a noticeable gap between bath and tiles, or tiles will gently slope. Although the mastic etc is all done, I guess this can be removed and the bath can then adjusted; still, it's a bit annoying that the installers left it like that.
3. The floor has too much bounce. It's obviously easily fixed, but the installers said they were finished and it was ready for the tiler.
4. The niche hasn't been fitted as agreed with the installer: There's not enough space for the tiler to actually tile around it. I guess this can be fixed or we don't have a niche.

Overall, my main question is the first one: is it acceptable to put standard plasterboard in areas where there will be tiles (i.e., in shower)? The overall internet recommendation obviously is to use tiling board. However, is this over the top? Is it just standard practice to fit normal plasterboard? Or should the installer have at least checked this with us?

Also, this current post is a follow-on to this earlier "Bathroom installation leads to water damage - what do we do?" (same installers / same set of work). We're obviously starting to lose confidence in these installers, and are wondering whether to call it a day with them?

What do you all think? Many thanks!

 

[ShaunCorbs]

There’s two schools of thought but mine is either water proof plaster board and tank or marmox board and there water proofing system etc you can use normal and tank but for the extra cost and piece of mind etc

The bath is just bad workmanship

Was this part of there quote ? Eg yo lift the floor and strengthen and then infill the joists with flooring and then marmox board over the lot ready for tiling adds a day and a half to two days plus materials

Size of opening agreed with installers ?

 

[John__]

There’s two schools of thought but mine is either water proof plaster board and tank or marmox board and there water proofing system etc you can use normal and tank but for the extra cost and piece of mind etc

The bath is just bad workmanship

Was this part of there quote ? Eg yo lift the floor and strengthen and then infill the joists with flooring and then marmox board over the lot ready for tiling adds a day and a half to two days plus materials

Size of opening agreed with installers ?

Thanks for the response, that's helpful.

It was definitely part of the quote to remove the old floor and make the new floor fit for tiling. I don't know the details off hand, I don't think the quote went into this, but I'll check.

The size of the opening for the niche was agreed. In particular, it was their main guy who pointed out that you'd need 100mm around the niche; so we agreed where the niche would go and that it would have 100mm around all edges, to tile easily. However, the niche has now ended up 30mm above the bath.

Your comments about plasterboard apply both to the floor and to the shower area, right? Or just to the floor?

 

[ShaunCorbs]

If they removed the floor they should of strengthened

Sounds like just poor planning on there part then

In regards to what the tabking normally you don’t tank a whole floor just the tray areas depending on if it’s a tile in tray etc

 

[Timmy D]

Niche needs to be higher.

If back to the studs, and I have a choice of covering before tiling, I’d never use plasterboard in the shower or any zone 1 area.

I’d always remove plasterboard and replace with wediboard in a shower.

Bath obviously needs to be level.

Floor needs to be solid. What covering is on the floor for tiling?

If floor boards and floor height permits, I’d add a layer of ply. If height is an issue, I’d lift floor boards and add 3/4 or inch ply.

What type of shower tray? Wet room?

If tray, is it raised with a plinth? If so, I wouldn’t want a riser kit (legs) used but a solid base built out of 4x2 and ply.

What shower head? Fixed arm and can/waterfall head? If so, make sure there is a solid fitting (back plate elbow) in the wall for the arm to screw into. I hate hack jobs with plastic/pushfit/unstable connection, makes the arm wobble a bit.

Got any pics?

 

[John__]

Niche needs to be higher.

If back to the studs, and I have a choice of covering before tiling, I’d never use plasterboard in the shower or any zone 1 area.

Good point about the picture - attached to this reply.

It's a bath with shower in bath. The wall behind the bath was taken out completely, because the supports didn't fit the placement of the Grohe unit, so the recommended action was to just remove all of the supports and rebuild the wall. You can see where the horizontal support runs (which is new), and it's too close to the niche.

I’d always remove plasterboard and replace with wediboard in a shower.

As everything was taken out, it would have been very easy to do that.

Floor needs to be solid. What covering is on the floor for tiling?

If floor boards and floor height permits, I’d add a layer of ply. If height is an issue, I’d lift floor boards and add 3/4 or inch ply.

The floor boards were removed, and there's ply. Probably about 3/4 or 1.

What shower head? Fixed arm and can/waterfall head? If so, make sure there is a solid fitting (back plate elbow) in the wall for the arm to screw into. I hate hack jobs with plastic/pushfit/unstable connection, makes the arm wobble a bit.

I think that will be fine.

Got any pics?

See below.

 

[ShaunCorbs]

Who picked the position of the toilet and controls for the shower / bath ?

 

[John__]

Who picked the position of the toilet and controls for the shower / bath ?

Hi Shaun,

That's on me.

Toilet: The bathroom is very small (around 2m by 2m). We went back and forth (including working with a designer) and this is the best position/arrangement that we could come up with (if we have a bath). The toilet was originally on the outside wall (and you can see the old opening for the old soil pipe), but that arrangement leaves very little space for a sink, unless you have a small sink behind the door. Like this, the door opens to the left; left wall has a towel rail, wide sink on outside wall beneath window. Image attached.

Controls: We wanted them centred, and to fit into a large tile, which makes them about 1500 high. It might be too high, but that's me.

If you think either is a mistake, please do say so. Open to suggestions and feedback!

 

[Ben-gee]

I would overboard the entire window wall go lose the gap at the end of the bath.

The plasterboard looks quite well fitted - I would use a liquid tanking membrane over that and the tile it. The worst bit of a shower is always the bottom foot, and as yours is a bath not a shower tray you will be fine with tanking.

I would either use hardibacker on the wall hung frame or I’d want ply behind the plasterboard- I’m not happy to just use plasterboard on its own.

 

[John__]

The plasterboard looks quite well fitted - I would use a liquid tanking membrane over that and the tile it. The worst bit of a shower is always the bottom foot, and as yours is a bath not a shower tray you will be fine with tanking.

The bath has a shower over it, which will have daily use.

I would either use hardibacker on the wall hung frame or I’d want ply behind the plasterboard- I’m not happy to just use plasterboard on its own.

You mean on the wall, in front of the wall hung toilet frame? To provide a harder surface for the toilet to sit on? The plasterboard will have tiles on, and then the toilet bowl.

 

[ShaunCorbs]

There’s a lot of force on the tiles and plasterboard your behind needs to be solid

 

[Timmy D]

I agree the gaps at ends of bath need to be lost. You want the tile sitting on bath lip and ideally the tanking to come down on to bath or you’re relying on the silicone to prevent water getting under the bath (it will happen when the silicone fails and you don’t notice straight away.

Also plan/frame/board(ply) for an access panel to get under the bath to access the waste etc. Secure the panel with silicone, not grout.

And ply behind toilet.

I would likely centre the cubby. You can then reach it from the bath laying position and potentially while showering.

Where it is now, is bad idea. Difficult to reach when laying and too low and close to wall.

 

[Tomik68]

We did bathroom and kitchen renovation last year and fitters which we used- they put green plasterboards+applied water sealant, only then tiled. Green plasterboards a bit more expensive, but is worth it.