Hi - my plumber has just installed a shower tray, and it would be very difficult to remove. However, the tray is not very well supported., and flexes when stood on. It was supported with mortar, but only in a few areas (for some reason), and these blobs of mortar have not stuck in place so they can be pushed around with a stick...
However, I can get access with a hose to the cavity under the fibreglass tray. Can anyone suggest some sort of filler I can pump into the void, which will set hard enough to support the tray well? I'm concerned standard expanding foram may not be up to the job...
Cheers,
Ben