Potential issue as XPS tile backer boards not joint sealed

[v12sv8]

Hi all

I may have a potential issue with some work a builder has done / is doing in a new shower room and would like to understand what could possibly happen and how to rectify it at this stage.

So currently, the builder I'm using has put NoMorePly 10mm XPS tile backer board on stud walls. I discussed using these with the builder and picked them as they were a good choice for being waterproof.

However, the builder has not used the recommended NoMorePly products such as the recommended Tile Backing Board Screws + Washers or the recommended NoMorePly Mega Strength Tile Backer Board Adhesive or the recommended waterproof jointing tape such as the NoMorePly Waterproof Tape.

Instead they have just normal screws to fix the XPS Tile Backer Boards to the stud walls, along with THIS PRODUCT - Sticks Like Clear All Weather Adhesive to glue it down. However, they have not used the Sticks Like Clear Adhesive within every joint line, nor have they used any waterproof jointing tape whatsoever!

I noticed this after all the XPS tile backer boards were in place, but thought the waterproof jointing tape or sealant would be put all over the XPS tile backer boards wherever there were joints before the tiles were laid. Unfortunately I went to work and came back to find most of the tiles were fixed to the wall but no waterproof jointing tape or adhesive had been laid across any of the exposed joints.

I did question the builder about this and was told it wouldn't be a problem, that they do this all the time, and that the grout and the silicone would mean no water would ever get through.

However, after speaking with someone at Topps Tiles today they said the grout wouldn't prevent issues if the XPS tile backer boards haven't been waterproofed / joint sealed etc. The staff member I spoke to seemed quite nervous that the job wouldn't last!

Therefore my concern is that over time, or even immediately, moisture is going to penetrate the wall structure and I'm going to end up with mould, damp, failing tiles and ultimately the job needing to be re-done.

My questions at this stage therefore are?
1) How likely is it that my tiles and the walls behind etc are going to be ok?
2) Is there a particular grout & sealant I can use to prevent moisture / damp issues and also try and prevent ultimate failure of the tiles etc?
3) Do I re-question the builder and insist the job is started again?
4) Any other suggestions please?

thanks in advance, feeling quite stressed and frustrated with this as I don't want to be paying thousands of pounds for a job that isn't going to last or is going to cause other damage to my house.

 

[Wayners]

I tiled over plasterboard 20 years ago in my bathroom.
I have a shower above the bath and everything is fine. That said.
Using products now you just need to read the application data sheet online, and follow the manufacturers installation guide.
You get some product warranty that way and know it's done correctly.
I don't know why trades don't do this. Maybe it's cost or not enough money in job.
Maybe it's just a lack of knowledge.

 

[robinbanks]

Maybe it's just a lack of knowledge.

And a sprinkling of hubris. They know better, because they always do it that way, and it never went wrong

 

[v12sv8]

So just thinking if the existing tiles can't be taken off and redone etc, would epoxy grout last and be a quick-fix solution?

 

[drives]

Agree with above- 100% use epoxy grout in wet areas. Why anyone uses porous cementitous grout in shower areas, I personally don't understand. It is not only non porous but also much more structurally sound as well so far less prone to cracking.

Taking into account what your builder has done thus far, they will moan that it is more difficult to use. It is, but not that difficult. It is a fair bit more expensive but perhaps that balances out their lack of proper prep work, by covering the extra outlay.

Realistically if water penetrates through the tile and grout you've likely got problems anyway- just minimised if the backer board is installed properly as well.