DaveChester wrote:
Hi guys,

First post although I have been reading on various subjects for a
while.

I have purchased a Grohe frame which I have bolted to the wall and
floor, covered in 18mm WBP ply and then tiled. I left it a day or two
and then bolted the toilet on, no problem.

I have now noticed that the bottom two tiles have cracked from the
pressure of the toilet bearing down (toliet anchors at the top so there
is quite a lot of pressure near the U bend). I am quite heavy but
obviously I cant have this happening again. Has anyone any tips on how
I could do this better?

I thought I did the bolts up pretty tight (the toilet would not move by
hand). Should I hav eput something between the porcelain and the
ceramic tile or waited longer before sitting on it?

Any help greatfully apprecaited.

Dave

18mm WBP is pretty soft. I'd say it has distorted locally.

Either do up less tight, or munge some silicone behind to spread the
load. Or use better tiles..