Hi. I am a complete amateur about to retile my shower that that is backed by marine ply. I realise that ply is not favoured here but the shower is 20 years old and the ply still looks fine after that time – it does not appear to have moved or degraded at all. Nevertheless, I thought I would take the precaution of tanking it (I propose using the Dunlop kit).
What I would like advice on is, which tile adhesive and grout would members recommend that I use on the tanked ply surface where I am fitting 25cms X 25cms X 5mms ceramic tiles?
Any other tips would be welcome.
Many thanks

Welcome to the forum.

Can you post pictures of the shower as it is now?

hmm, if you're keen on retaining the ply, I'd seriously think about overboarding it with 6mm hardibacker 250 and then tanking it if there's room for it.

Thanks both for your replies.

I will see if I can post pictures later. As far as the hardibacker is concerned an additional 6mm or so may take the external face of the shower enclosure over the edge of the shower tray.

Whichever approach I adopt, I would appreciate thoughts on the most suitable adhesive and grout to use.

Many thanks

(Apologies if this duplicates an earlier response from me - my last two attempts to post a response appear to have vanished into the ether!)

i'm with doug on this one 6mm boards would be better and less prone to any water damage

Better safe than sorry. Iv seen ply bubble in places lately with Bal tanking ! I refused to tile it so got boarded too. Plywood is not what it used to be unfortunately.

i doubt your gonna get anyone comitting an answer hamfisted, as most of us wince at the thought of tiling on ply.

i know i shouldnt but i done a job last week new build property 2 walls were solid and 2 were ply he didnt even want to tank but i insisted so i tanked and i tiled them with300x300 polished porcelain. i didnt want to turn work away so i did it some times we have to even if we dont agree but this developer gives me regular work so i bit the bullet this time but told him in future to use no more ply or backer boards for all the difference in costs and he wont get any come backs so he agreed so a result for us tilers in the end!

luckily enough i've only tiled onto ply on walls once and that was a splashback in a joiners house,and he only used it because he "borrowed" it from site and his walls were a riot! don't think i would tile ontoit on a bathroom or wet area though!

Originally Posted by garretridge

i know i shouldnt but i done a job last week new build property 2 walls were solid and 2 were ply he didnt even want to tank but i insisted so i tanked and i tiled them with300x300 polished porcelain. i didnt want to turn work away so i did it some times we have to even if we dont agree but this developer gives me regular work so i bit the bullet this time but told him in future to use no more ply or backer boards for all the difference in costs and he wont get any come backs so he agreed so a result for us tilers in the end!

What is it with developers?? I've just done some bathrooms for one and out of the 8, 1 was just plasterboard 5 were plastered and 2 were half plasterboard and half plywood, Makes life that bit easier ....... NOT

Use a tanking membrane, done ri ght first go then, these liquid kits have to be applied correctly to the right thickness or it is worthless doing it.. So i always use membranes..

Dural wp is a top one..

I've just had to do a plywood shower cubicle. I tanked with a membrane (stuck using a rapid set flexible addy) then used a flexible cement adhesive to fix the tiles. I left sufficient silicone joints top and bottom as well as in the internal corners, so fingers crossed - lol.

The trouble with ply also is if it gets damp some of the resin seems to make the grout go brown

Many thanks for all your replies. Much appreciated.

Help please!! Had my tiler around last week to look at my cracked tiles in teh shower. All was not well.....water had been got into the plasterboard and mold was growing. Plasterboard was falling apart...yes that bad. Anyway one of his building mates he recommend is going to removed the shower and remove old plasterboard and replace with 12mm plywood. The tiler is then going to stick this 100% waterproof membrane (aparantely its new £50 a role & only just on the market) onto teh plywood upon which the tiles will be stuck & grouted. Having reviewed the comments about plywood, I'm a little uneasy about using it now. Can anyone confirm if this is suitable for a shower? The builder/tiler state that this new membrane is 100% waterproof & thus if water did get through the grouting, no water can penetrate the plywood (which is my biggest concern given woods dilike to mositure) due to this 100% waterproof membrane. Can anyone advise if this sounds acceptable?

Its not about waterproofing its to do with the movement in the plywood.

Personally i would just use 12.5mm plasterboard and then use the membrane over that, less chance of thermal stress and cheaper..

Membranes have been on the market for a few years now.. make sure the joints are over lapped by 50mm or the joint tape is used.. to seams and internal corners etc..