Tiling in a sower bath area

[Xenophya]

Hello,

I’m new to this forum and new to tiling so please assume I know nothing when replying!!

A month or so ago we noticed a water stain on the kitchen ceiling below where the bathroom is in our house. Removing the bath panel revealed that water had been running down the wall. My first thought was the bath seal had been letting water in when we were showering so I re-sealed the edge with silicon. After 2 attempts at sealing it I started to spray the shower at different areas around the bath/shower to try and discover where the water was coming from. After ruling out the bath seal I realised that the water was getting through cracks in the grouting and running down behind the tiles through the plaster board past the silicon. A little more investigation saw about 2 thirds of the tiles come off the wet wall.

The whole bathroom is old and in need of redoing so I have taken a couple of weeks off of work to re-tile the whole room and replace the suite.

Now to my question, how do I avoid this happening again and wasting a lot of money on new tiles? The walls look to be stud work and plaster board. Although the plaster board got wet it appears to have dried out now and after some poly-filler work is pretty flat again, but there is some (1mm or less) movement in it. I have read about tanking on these forums which I understand will make the wall water proof but if the grouting cracks again what will stop water running down behind the tiles and damaging the kitchen ceiling again?? Any suggestions greatly appreciated.

best regards

Mark.

 

[Softus]

If the wall isn't rigid then don't even start tiling - a floppy/flexible wall will lead to the grout cracking again.

I would investigate the reason for the moving wall and sort it out. It might be the battens behind the plasterboard, or it might be the board itself. My preferred method for shower areas (unless you can get back to brick/block) is to line with 18mm WBP plywood on battens - this has never let me down, but many people regard this as too expensive.

If you buy an acrylic bath, don't buy anything thinner than 8mm. When you install it, ensure that it's fixed solidly to the wall - you might need to plan ahead and put noggins between the battens to make the wall more rigid and to accept screws for angle brackets.

When the bath is in solidly, tile up from the bath deck leaving a 2mm gap for later sealing with top quality silicone.

There are various topics dealing with the stages involved - break your project down into achievable stages, buy good quality materials, relax, and enjoy it.

 

[Xenophya]

Hello Softus,

Thanks for the speedy reply.

It really is very appreciated.

So are you suggesting I need to screw new wooden batons into the wall (on top of the existing plaster board) then screw ply on to that? Or are you saying I need to strip out the existing plaster board and replace it altogether with Ply fixed directly into the batons?

The bath we have bought is a GRP shower bath (one of the ones shaped like the letter P). As the door opens past the bath there should be (at the closest point) 75mm between the edge of the door and the bath panel which is tight but acceptable. It does however mean we don’t have a lot of space to play with.

If I can at all avoid it I’d really rather not strip out all of the old plaster board. The bathroom is only small (the main wall the bath runs along 1700mm x 2300mm and the area inside the shower screen on the back wall 870mm x 2300mm) so I had thought of getting MDF sheet, 18mm or 16mm thick. On the larger wall I would cut it into two sections (to get it into the bathroom through the door) and fix it with screws straight over the old wall. I would cut the sections so the join runs horizontally just below the height of the bath rim. This would give me a single flat stiff surface without any joins above the bath rim right up to the ceiling which I could then seal with BAL-WP1 tanking kit and tile over?? Would this work or maybe if I did this but used the ply you suggest instead of MDF?

Thanks again for your advice, I really can’t afford to get this wrong so it is greatly appreciated.

Mark

 

[Softus]

So are you suggesting I need to screw new wooden batons into the wall (on top of the existing plaster board) then screw ply on to that?

No I didn't mean that.

Or are you saying I need to strip out the existing plaster board and replace it altogether with Ply fixed directly into the batons?

This is going to sound evasive, but I wasn't recommending removal of the plasterboard unless that's the way to make the wall firm.

...I had thought of getting MDF sheet...

Whoa there - don't use MDF anywhere moist or humid.

...maybe if I did this but used the ply you suggest instead of MDF?[/quote]
That would be better. And make sure it's WBP plywood.

 

[Xenophya]

Whoa there - don't use MDF anywhere moist or humid.

Consider my horses held, no to MDF then.

I just had a look on Wickes’ website and they do Exterior WBP Plywood Size: 2440 x 1220 x 12mm for £19.99. Will 12mm be thick enough?

Should I also use the BAL WP1 Waterproof Shower Kit or is this overkill??

Thanks again for the advice,

Mark

 

[Softus]

I just had a look on Wickes’ website and they do Exterior WBP Plywood Size: 2440 x 1220 x 12mm for £19.99. Will 12mm be thick enough?

IMHO, no. I only ever use 18mm for anything that needs to be rigid.

Should I also use the BAL WP1 Waterproof Shower Kit or is this overkill?

Hmm. For a bath area I've never tanked, so yes it would.

 

[Xenophya]

Excellent.

Thanks for the advice, I'll let you know how I get on.

Mark.

 

[Xenophya]

Hello again,

The main 1700mm wall for the bath is now lined with the 18mm ply and as a result is solid.

The extra 18mm has however thrown up a problem with the existing shower on the smaller 550mm wall. I know this is not really a tiling question anymore but it might be something you have come across. Adding another 18mm to the depth of the wall means that the water pipes which connect to the shower (the control assembly part) no longer protrude far enough to get tiles behind. The fitting is a compression style with an olive )which seams stuck in place on the pipe) and the pipe only stick out from the plasterboard face (before adding the ply) by 15mm. I can put an extension on using something like a Solder Ring Imperial/Metric Adaptor 15mm x 1/2 Inch (on the b&Q website) but this will, I think, then make the fitting the too long.

Any ideas?

Thanks again for the continued advice I really would be lost without it.

Mark

 

[gcol]

Softus and myself have had many a "discussion" regarding the use of ply for shower area substrates. I won't go into the ins and outs, but if you want my opinion, rip out the wall material down to the joists. Replace with new plasterboard (more stable than ply), tank it (including the joint to the bath) tile over using Bal white star and grout with a decent powdered grout.

 

[Softus]

Xenophya, there is no perfect answer or method, and I would say that gcol's favourite method is at least equally as valid as what I've suggested.

Regarding your new problem, I didn't expect you to erect ply on the top of plasterboard, but to replace it, and in the process to ensure that the battens were secure.

Anyway, now that you've done it, I think you have to extend the pipework.

Could you post a picture so that I (or anyone else who wants to) can get a firm grasp of the dilemma?