Cracked grout lines

[stevepybus]

Hello everybody I need help on this one I have just tiled a bathroom floor with underfloor heating and then grouted it the next day the a couple of days later I noticed 2 tiles had cracks running along the line everywhere else seems fine apart from these 2 tiles what's the best way to sort this out do I just re grout or is there other problems I should be worried about ?
Many thanks steve

 

[gamma38]

Hi Steve, some more info is needed really. What was the floor constructed of, what did you lay the underfloor heating on, did you cover that with anything or just tile adhesive, what adhesive did you use, more importantly did you turn on the heating as your supposed to wait two weeks after the completed job and then only onto it's lowest setting increasing by one degree per day.

 

[stevepybus]

Hello gamma38 thanks for replying sorry should have said the underfloor heating was ontop of 9mm ply screwed at 100 mm centres then I tiled over top with webber flexible adhesive then grouted it havent had underfloor heating on yet but it was a very hot day when I grouted it if I do have to regrout what's the best way to do this as don't want to damage underfloor cables? Thanks steve

 

[gamma38]

The webber flexible adhesive should be fine. Good quality. 9mm ply is definetly a no no. It should be 15mm ply that's the minimum. That said I have never used ply under heating as it's not a suitable substrate. You should have used a reputable insulation board or backer board, hardie or warm up. That said what did you lay the ply onto? Floorboards or chipboard? Your floor should be sound and deflection free. With underfloor heating due to the expansion and contraction you have to be even more carefull with your project. The worst case scenario for you could be failures due to the 9mm ply etc and the end result can be a redo.

 

[gamma38]

On a side note as well tiling straight onto the cable is something I don't do either, I cover with selflevel compound. Combined with a screamer attatched to the wires, this tells you if you cut or damage the cables during installiation, by screaming.

 

[stevepybus]

thanks for the reply again and yeah screwed the 9mm ply onto chipboards i would have then poured self leveler but i had a wet room tray down and was worried about the tray but i did everything recomended by the tray manafucter they recomended to put 9mm down i hope i dont have to do this again already behind on this one

 

[gamma38]

What make of tray was it. How thick is the tray? Wet rooms I would normally remove all flooring, fit noggins as necessary then lay 18mm wbp ply at least then on top of that the backerboard. Then tanking membrane then tile. Never had a call back or failure whether underfloor heating or not. My gut would say to be concerned with chipboard and 9mm ply to be honest. Not what you want to hear I'm sure.

 

[Colour Republic]

Worried about the tray? Is this a wetroom?

 

[stevepybus]

Hello again the make of the tray is orbry and I did take chipboards up fitted noggins then 18 mm ply then tray ontop of that I was then left with 9 mm difference as tray was 30 mm thick so put 9 mm ply down everywhere else seems fine just these two near door but I did leave it another day to grout them could that have been the problem

 

[Colour Republic]

So it is a wet room... did you tank the floor i.e. did you waterproof the floor in anyway

 

[Saltire69]

So it is a wet room... did you tank the floor i.e. did you waterproof the floor in anyway

Thats what i was thinking.

 

[stevepybus]

hello again everyone sorry its been a while been up to my eyes anyway, yeah i waterproofed the floor but managed to find out the problem i used the wrong adhesive :mad2: it said on the bag suitbutable for underfloor heating and i thought i had used it before but obviously not so had to take whole floor up which broke the underfloor heating so having to do the whole floor and underfloor heating again customer isnt impressed to be honest feel a bit let down by the tile company that supplied the adhesive because when all the gear arrived there was 3 bags of rapid set in blue bags and 2 yellow bags of weber what i thought were for the floor because i thought as there is more tiles going on wall thats what the blue bags are for anyway thanks everyone for the great advice as usual

moral of story read the adhesive bags properley

 

[White Room]

All else fails read the instructions :lol:

 

[Ian]

If you're having to redo the whole thing, do it with an insulation board instead of ply and, make sure you SLC over the cable before tiling.

 

[stevepybus]

Hello again thought I post a few pics of finished job lol