wet room grout problem - TilersForums.co.uk | Tile Forums

NickMizen · 19-06-2007

Hi! We have just had a semi wetroom installed (tiled shower floor, but with shower screen). The wall and floor tiles are porcelain, with the floor tiles having been laid on marine ply over the dry floor, and a moulded base with drainage laid under the tiles at the same height as the ply for the wet shower area. This was installed approx 3 weeks ago. A flexible grout was used that can be submerged in water. Not sure what adhesive was used.

In the last week the grout has, I think, started to leak. When you stand on the tiles the grout "bubbles", which I presume is water that has got under the grout being squeezed through. Or is this just flexible grout being flexible?

My Tiler has scrapped some of the grout out, and replaced with a non-flexible grout. But the same thing has started to happen again.

Any ideas on what I need to do to rectify this? I don't want the area to leak into our kitchen, but know that if I need to take the tiles up and re-do the adhesive then I will ruin the moulded shower base - very costly!
Any advice would be very appreciated.

**Dave** · 19-06-2007

when you say moulded base is this the substrate which has been tiled on or is it just the ply. if it just the ply then it should have been tanked to make this water tight, flexible adhesive used and a flexible grout , these products are water resistant not water proof so its sounds as if you have water ingression in the substrate and will need to lifted and done properly. i.e. any substrate to be tanked ( water proofed )

**brian c** · 19-06-2007

Quote:

Originally Posted by dhceramics

when you say moulded base is this the substrate which has been tiled on or is it just the ply. if it just the ply then it should have been tanked to make this water tight, flexible adhesive used and a flexible grout , these products are water resistant not water proof so its sounds as if you have water ingression in the substrate and will need to lifted and done properly. i.e. any substrate to be tanked ( water proofed )

good advice Dave.

**uug197h** · 20-06-2007

did your tiler use a wet room Membrane ? (this is like a rubber mat that sticks to the floor and 75mm up the walls) then tiled over

NickMizen · 20-06-2007

Thanks for the reply

.. The shower area tiles are laid on a wedi style shaped tile former . Using flexible adhesive and grout ( Bond it wood flex and wide gap grout ) all corners had been sealed with the with a rubber tank also . I feel the problem lies with the grout . .

**Dave** · 20-06-2007

as long as subfloor is water tight you shouldnt be having problems, are you sure the grout was modified..

NickMizen · 21-06-2007

Initial grout used . ( Bond It Wide Joint Compound , Flexible ) Which is a cement based , highly polymer modified joint filling compound . . We noticed bubbles coming through the grout when walking on the tiles after a shower .. Upon of inspection of the grout ,it was really soft in places ..
We left it to dry for a week and it was still soft so we then scraped the soft grout out and thought we'd try some hard set grout . This has now done the same (and gone a bit dusty ).. we've been having baths for a week now an the grey grout is still a little darker than the rest of the floor ( only very slightly ) I'm thinking of scraping all the grout out this time and letting it dry for a further few days .. What would your plan of attack be then ? Thanks again for all your help so far ...

**Dave** · 21-06-2007

rake all the grout out and leave to dry, then re-grout with epoxy grout this should resolve your problem , tip is to use an emusifying pad to remove the thick of the epoxy and finish with a sponge.. hope this sorts your dilemma... dave......

NickMizen · 21-06-2007

Thanks for all your help Dave .. You and everybody else have been very helpfull