Tiling on plywood walls

[EEJAY1196]

My shower cubicle has 2 plywood walls that have been tiled. The grout joints on these 2 walls keep getting hairline cracks low down where it gets wet the most and this is now causing some tiles to move and loosen, probably due to water getting in. Any suggestions on what can be done to cure the problem?

 

[masona]

What is the gap between the tiles, if it's too close then I'm afraid you will have long term problem, or the tiles not fitted onto the plywood with enough adhesive to causing it to become loose.

 

[thebrick]

not to get you worried mate but the plywood walls the tiles are fixed to should be formed using marine ply and fixed to the stud work with screws not nails and fixed at every 150mm. Also i agree with Masona if there is no gap between the tiles ie no spaces were used when applying the tiles then you will have continuing problems.

 

[EEJAY1196]

Thanks for the replies, to answer your questions. The walls are made out of marine ply and are screwed to the stud work. Tile spacers were also used so there was a reasonable gap to grout into. The 3rd wall is a regualr brick amd plaster wall and it has no problems at all.

 

[emin-j]

Hi Mate,I had a similar problem after I extended the bathroom into the back bedroom to create enough space for a shower cubicle,I also used timber boards for the shower surround and mounted tiles on that.But being in the timber trade at the time I did know how timber would "move"
due to the changes in the humidity of the room so with this in mind I coated the boards with building adhesive Unibond which I believe is also a waterproofer.I then tiled and grouted using a standard showerproof grout
only to find hairline cracks appear in the vertical joints of the tiles.So I dug out the grout and replaced it with waterPROOF grout which I think was made by Evostick this grout was also claimed to be flexible (so to move with the wood) and so far so good ! one tip is not to take out to much of the grout from between the tiles when your cleaning up and make sure you leave a good depth of grout between the tiles.