Cracked tiling around shower control

[stevew49]

We've recently had a shower control unit recessed into our external bathroom wall, taking out some of the brickwork. The hot and cold pipes have also been cut into the wall. The work was then covered with nice (quite expensive) tiling. After only a couple of months, the tiles around the control unit and pipe to the shower head started to bulge and crack. Our builder came and looked at the damage, took the tiles off and said that there was no leak causing the bulge - he thought it was due to movement. Although there is some movement in that part of the house (we're on London clay!), the way the bulge is just around the control unit and pipe makes me think it's some sort of insulation problem. He replaced the cracked tiles with new ones, but after only a few weeks more, the same problem recurred, worse if anything! Anyone got any suggestions or think of reaons for this. We've spent a load of dosh on it and it's looking rubbish after a very short time... There's no evidence of movement externally. Any help much appreciated!

[Quiche Mash 'n' Mushy]

I suspect the builder used boggo standard plasterboard as a base for the tiles.

Quiche

[Tim Mitchell]

In article , Quiche Mash 'n' Mushy writes

Sounds like the shower mixer valve isn't fixed to the wall firmly, and that is what is moving and causing the surrounding tiles to crack.

[sm_jamieson]

Has allowance been made for the expansion of the unit and pipes when it gets hot ? How are the cut-in pipes back-filled ? Simon.

[Ian_m]

My mate had a similar problem like this on 7 year old shower in 2nd bedroom ensuite, so not used a lot, the tiles near the valve cracked. Was caused by a leaking joint on the shower valve, dripping onto the various layers of plaster board and causing them to expand and crack the tiles. When plumber removed the tiles, plaster board underneath was just "bulged", causing tiles to crack and also bone dry which was very confusing. When he cut this away found about 4 layers thick of plaster board, on batons, with the layers nearest the wall soaking wet, crumbly and expanded. The leaking water was just running back into the wall. I assume the multiple layers of plaster board were to make the shower cubicle the correct size for the shower tray.

Anyway all was ripped out, replacement plaster board and tiles put back and shower valve refitted, this time without the leak.