waterproofing a shower

robwend

hello there, i need some good old sound advise, had a cowboy builder make me a recessed shower. just used plywood to build it , what i need to know is how i make this thing water tight,as plys pourus, and i dont want to spend a arrm and a leg neither ,or be too cheap and have damp problems later, do i have to plaster over ply first? or can i but special waterproofing paint then just tile? i have NO IDEA! please help me with theis one, as hubby didnt want the damm shower in the first place! lol so ive got to get this right xxxwendy

Lewis_Gerolemou

I painted my plywood shower with two coats of oil based (not acrylic) pirmer then fixed tiles with tiling adhesive. You must use a good quality grout, I used a two pack epoxy one but i don't know if it is still available. With a shower the grouting is most important because obviously that is where the water will get past the tiles. Make sure there is enough gap where tiles meet shower tray to get a decent bead of silicone mastic in. One of my showers was done 20 years ago, some of the mastic needs raking out and replacing again but the grout is still rock hard and in place.

griff.

robwend

you could

a) buy new plasterboard panels from B&Q - enough for the average shower area will cost you £10 or so, nail and stick them up, then tile them properly with a good adhesive grout, and seal the connecting edges to the shower area with sealant

b) buy waterproof panels (cladding) that slot into each other - dunno their current price, but saw them at B&Q recently and thought they were quite cheap and would probably do a good job. There are some dearer examples available on the web - have a look at http://www.absealantsltd.com/decorative_cladding.htm to give you an idea.

It sounds as though it's a smallish area that you are doing, so hopefully shouldn't cost too much.

jimmmyc

I tile shop I went to had something called tanking I think which looked like very thick paint and it waterproofs anything.

superjaggybunnet

If you buy plaster board panels make sure that they are the right kind. Normal plaster board is no good, it needs to be the green plaster board. If the normal stuff gets wet at all it just falls apart.

robwend

thank you so much guys, im going to look into this "tanking" hopefully a nice mr band q man will help me out xxxwendy

Lord_Gardener

I also primed plywood and then fixed tiles. Plenty of info available at B&Q. It's the tiles, grout and mastic which provide the waterproofing!

moneysavingplumber

Is it marine ply? I tend to prefer marine ply for showers as it is less prone to movement than moisture-resistant plasterboard, which helps prevent grout from cracking in the future, although this depends also on how good the stud wall is and on whether single sheets have been used as far as possible to avoid joints midway through a wall section which will also encourage movement. Usually sealing it with PVA will allow you to tile straight on to it. The tray should be sealed with sanitary grade silicone against the ply first, then the joints between tiles and tray should not be grouted but siliconed as well, and I always prefer to seal vertical corners with sanitary silicone too.

BobProperty

Me posting this link is getting a bit of a chore:
http://www.trustedtradesmen.com/forum/forum_posts.asp?TID=4930&PN=1
see the picture sequence on how to do it properly.

Now we start on the most popular argument in tiling and bathroom forums, the use of PVA. Don't, it isn't waterproof. That's what I've learned off experts and I cringe at seeing so called professional builders using it on TV programs.
See
http://www.ultimatehandyman.co.uk/tiling/diy_Tiling_Why_not_to_use_pva.htm

Edited to add that the best place to get a tanking kit is likely to be Topps Tiles not B&Q.

John_3:16

Some PVA is waterproof as it says on the tin.

BobProperty

John_3:16 wrote:

Some PVA is waterproof as it says on the tin.

This is where the arguments start. The other side is that the additives needed to make it waterproof, would leave it open to question as to whether it still really should be called PVA. Either way you don't need it for a shower wall, there are primers and adhesives made by eminently repectable manufacturers which will do the job and that they will guarantee. They won't guarantee their products if you have used PVA, "waterproof" or not.