Tiles Cracked in New Extension - Help Please !

[DAK]

120cm apart cracks suggests along the joints in chipboard rather than joists which would be maximum 60cm apart but mior like 40.

Thanks for the insight. In terms of resolution of this do we need to do something with the chipboard floor? Obviously we need better tiles. Would ply or cement board resolve?

 

[Tile Marble Granite]

Suspended floors speaking, the joist is the most important, the bouncing comes from the joist, 18mm ply is a must as chipboard is totally unacceptable for a floor, lol. As far as I am concerned cracks are related to bouncing

 

[david mccullough]

you say that the floor is 40m2, that's a big room, is it 4mx10m, 5mx8m?
7"x2"joists seem a bit light for that size of room unless there is support walls, in the correct places, the quality of the tile shouldn't come into it, or the use of chipboard, i take it the tiles aren't boast? in my experience the better quality the tile the more brittle the tile, the main problem is movement, the fact that it still cracked even with ditra is surprising, there must be too much movement,
fill a glass of water, set it on the floor where there is the most movement and bounce on the floor, if if there is any more than mild ripples the floor isn't supported enough

 

[Slippery]

a 7 inch joist will shrink by around 5-7mm when brought in from the builders merchant under normal conditions, put heated pipes next to it and you could expect maybe another couple of mm, that's what I suspect may have happened but the tile choice is the bigger part of the problem IMHO

 

[Nigel cheltenham]

I’m a joiner 40 years I have always overlaid chipboard with 18 mm exterior grade ply screwed and fixed every 150 mm lay ply opposite way over chipboard I personally would never tile onto chipboard as I think their would be too much movement in floor

 

[demi34]

They should put hardie boards on the floor stuck with adhesive and plenty of screws