Travertine crack accross 4 tiles

[DavieA]

Hoping for a bit of advice.

Called back to a tavertine job i did about a year ago for a mate. Found 2 seperate cracks that stretch in a straight line accross width of the floor and beleive there where the 15mm ply sheets butted together, therfore think there must be movement in floor?

Ply was screwed in to floorboards to ensure no bounce and obviously floorboards arnt suitable to tile on and used flex addy and grout along with thick bed fixing method.

Told my mate to add dwangs inbetween joists from basement to stenghten bathroom floor is this a good more to solve this problem or whats the best remody?

Thanks guys

 

[jay]

what thickness ply and name of adh would help

thanks

 

[DavieA]

It was 15mm and keraflex maxi Jay.

Cheers

 

[Rich]

Were the boards butted up together or was a gap left? There should be a small gap for expansion. Ply will expand and contract with moisture/humidity, if the boards are butted up together then they will "tent". This often causes tiles to crack along this line.
The tiles will need taking up whatever the cause, take them up and if there is no expansion joint, add one. It only needs to be 2-3mm.

Or it could be that the end of these boards are not sitting on the joists so that, as you say, there is a bit of movement causing the tiles to crack. This will need to be supported before re-tiling.

 

[DavieA]

I think they were butted together my mate did the plying. Think I will try strengthening floor and if problem persist put in 2mm gap in boards.:mad2:

Was ment to have a 45m2 travertine floor job but this has dented my confidence a tad and am unsure wheither to take job on.
Job comming up is over wet ufh aswell, intention was to overboard the chipboard floor with 15mm ply to ensure strength then lay dural ci+ and lay tile using keraflex on a soild thick bed.

What do you guys who have tons more experience than me think? Id be gutted if anything happened to a customers job.

 

[Rich]

I think you should just take this as a lesson. You have to know that the floor your about to tile onto is fitted correctly. I dont think you should go turning work down over this. Take the work but just swat up on here before each and every stage of the project. If this has knocked your confidence, just think how much it will improve your confidence when you complete 45m of trav knowing that it is done properly.

 

[DavieA]

Good advice, Thanks.

Would the steps listed be suitable or is cement boards recommended instead of ply? Mapei tech say ply is superb or ixing using there addy and i know 15mm would add strength.Ive been toying over this because i want a strong floor or tiling but heat to be passed through no prob and amnt 100% on 22mm chipboard+15mm ply then decoupler and addy.

 

[White Room]

Did you use a decoupler with the trav

 

[DavieA]

No not this time as no ufh and room was about 5m2 but do if ufh is involved and tiles are porcelain,travertine or another natural stone.

 

[White Room]

I find trav is soft so tend to use a decoupler on timber/ply floors..