porclain floor cracking !

[terry the tiler]

before i start i would like to state that i Did not tile this floor !! its a mates job. he wanted me to tile it months ago but he couldn't wait so he tiled it himself !
problem is that after around a week after laying the tiles lines appeared in a line over a part of the floor.

the floor was floor boards over boarded with 9mm ply sealed under and sides of ply also stagard ply and left expansion gap.
tiles are large format porcelain from tops tiles.
adhesive was bal flexi
grout was bal flexi
both supplied by tops!
any ideas as to why there cracking ? it seems to be where you would get the most foot trafficking from the door to the bath. wot gets me is that none of the grout has cracked ? thought it may of been a batch of faulty tiles at first but he said he mixed the tiles up before laying them. also not sure if he back buttered tiles or not !

[mikethetile]

9mm is inadequate for overboarding under tiles. you need 18mm

[TF Ed]

straight line crack = stress fracture
inadequate strength and support in the floor !

[united]

As Mike said you should overboard with at least 18mm Ply

[TF Ed]

its not always just about overboarding..its about the joists also being stable, braced and secured.....

the boards are only as good as the joists they sit on..

ps mikett and united know this, so i am not teaching them to suck eggs, just stating a point

[Sir Ramic]

9mm is not enough although lots of people do use it. Depending on the state of the original floor will make a difference but it should be minimum 15mm but seeing as 15mm is rare as rocking horse dropping then 18mm is next.

[terry the tiler]

thought it was that also but just wanted a 2nd opinion before i break the news to him over a pint or 12 guess who will have to sort it out ? .. . ha ha .
so how would you lot tackle it ? would you just sort out the floor where the tiles have failed and hope for the best or is it gonna have to be a full rip up and start from scratch job? cost him a small fortune for the tiles if i remember right.

[Dave]

It could also be the boards were put down tight against each other and you have a heave crack..boards pushing against each other and heave up and cause a stress crack..

Either way it needs to come up..

[united]

Sorry to say but I would rip up and start again and do it properly so it doesn't happen again

[terry the tiler]

the grout must of been made by superman as none of it has cracked but the porcelain tiles have ! well IL have to charge him for the privilege of ripping it all up , but its not gonna be a mates rate.

[david campbell]

personally i would forget mates rates,he's had his chance made a pigs ear of it by rushing in and not waiting,now you have double the work for a cheap rate

[whitebeam]

Some of the joints are a bit off angle, not that it matters as it's coming up

[diamondtiling]

Cant really add much to what the guys have said but its all about the prep before tiling.

[terry the tiler]

it is a v poor job, he is a painter by trade and obviously not a tiler! think i might tell him iam fully booked for the next 5 years and hope he gets the message

[Scott]

He'll thank you in the end as it will be a much better job once you have done it for him