Sealing Shower Tray with flexible grout.

[iamajc]

Hi, I'm a plumber with (after reading some of this forum, very) limited tiling experience. After fitting a shower tray at a friends house, it has been set on 18mm ply on floorboards and set into the wall by approx 20mm as corner not square, silicon sealant around back edges.
Friend has then filled remaining gap with rapid set cement and tiled themselves after I expressed doubts about how they wanted it tiled. More of how to set it out than anything else as they wanted to start with full tiles in the corners and let the tiles overhang the tray rather than cutting the tiles to fit flush with the end of the tray and starting centrally.
The wall are plastered with some holes patched with rapid set cement. The tiles are from wickes and are ceramic and printed to look like stone. They have stuck the tiles on with a waterproof adhesive mapia I think not sure if they read the distructions or if the sealed the walls first.
My main concern is that they are doing/have done the grouting today using a waterproof flexible grout(brand unknown to me). I mentioned that they may want to get some coloured sealant to try and match the grout as it is coloured grey. As personally I would seal the vertical corner as well as along the top of the tray as these are the obvious/normal places that the grout could crack up (have just read the sealing over grout thread) and follow the screen manufactures instructions for sealing the screen. They are telling me now that they are not going to use silicon at all as the grout is flexible and waterproof they do not need to use silicon.
Has anyone succesfully sealed a shower tray or bath using flexible grout alone???
They have already repaired the downstairs ceiling after their last shower leaked:mad2:

 

[Tony73]

Hi and :welcome: to TF. I would advice to use silicone all internal corners.

 

[kilty55]

hi you are correct what they have done will fail 100 percent

if they dont want your advice let them destroy there own home!!

 

[jindru]

its a pity they arnt near me.I make a good living from silly people who watch large stains appear in downstair ceilings ,then wonder how the water got there.kilty is spot on you can take a horse to water etc.

 

[StevieBoy]

A decent silicone will do the job no probs

 

[iamajc]

Thanks for your comments, I have now left the job unfinished as it wasn't worth the grief. They used thicker tiles than originally planned and more adhesive and where my pipes were they wouldn't reach the shower valve properly, I could have adjusted the pipes if I had tiled as it was obvious it wasn't going to fit correctly but after tiling and grouting they wern't impressed to be told I would have to remove 1 or 2 tiles. The corner starts with a 4mm gap at the bottom and opens to about 15mm at the top so I do hope that their grout is very flexible...God knows how you get that looking good with silicon, I would have got them to ring a silicon sealer man, let him laugh at it instead, And the tiles run off horizontally as well so when the shower valve goes near level it looks wonky compared to the tiles.
I should know better than to work like this. Initially I was fixing a leak under a raised quadrant 900mm shower, I pointed out two rotten joists both under bath and shower cubicle, they repair the ceiling under the joists planning on leaving the joists as where before then deciding doing the joists was a good idea after all they then threw a chippy out for kicking the rotten joist and damaging the repaired ceiling, then change shower from electric to mixer, then retile wall was blown so they sacked off my recommended plasterer and employed his brother who is nowhere near as good to plaster inside old shower screen rails, then changed shower to floor level 1200*800 then the tiling whole room to dado hieght then just shower cubicle blah blah blah
Of course it's all my fault and their changing plans on a daily basis is not a problem.
I wouldn't mind being a fly on the wall as the job continues as he is going to finish the job himself as he is going to buy a bar shower fixing kit, I even tried to explain that the kit was for stud walls not solid ones, of course to no avail.
I now know why he cleans windows for a living