Cracking in new bathroom floor tiles - cause? - update

hc25036

Had a complete bathroom refit almost a year ago and noticed a few weeks ago that the dead-centre floor tile had a hairline crack.

Checked today and the crack now extends the full width of the tile and also now has started to run through the next tile along the same line.

Nothing has been dropped on the floor and the other tiles look OK. Contacted the fitter to get them back, but what are the likely causes so I don't get blinded with excuses!

Hugbubble

hc25036 wrote: »

Had a complete bathroom refit almost a year ago and noticed a few weeks ago that the dead-centre floor tile had a hairline crack.

Checked today and the crack now extends the full width of the tile and also now has started to run through the next tile along the same line.

Nothing has been dropped on the floor and the other tiles look OK. Contacted the fitter to get them back, but what are the likely causes so I don't get blinded with excuses!

I'm no expert but a friend of mine had a similar problem and I believe it was due to laying the tiles on an uneven floor.

googler

hc25036 wrote: »

Had a complete bathroom refit almost a year ago and noticed a few weeks ago that the dead-centre floor tile had a hairline crack.

Checked today and the crack now extends the full width of the tile and also now has started to run through the next tile along the same line.

Nothing has been dropped on the floor and the other tiles look OK. Contacted the fitter to get them back, but what are the likely causes so I don't get blinded with excuses!

The floor below the tiles is moving. The centre being the part that is moving the most. If you want to test this, stand on the tile that's cracked and bounce your weight up and down on it. Can you feel any movement? Does the crack get bigger?

What did the fitter put down on the floor as a base for the tiles?

In our case, the original flooring was standard chipboards on wooden joists. Over this, our fitters fixed 3/4 inch plyboard, and screwed it down onto the chipboard at roughly 6 inch spacing, all over the room. This was coated with dilute PVA and the tiles fixed atop this. As far as I'm concerned, anything less than 3/4 inch ply is false economy.

robv_3

yeap, moving subfloor. normally cracks where joints in the board below is.

nickj_2

one of my friends had this happen to his tiles, the tiler had to rip out the floor , restrenghten the joists and floor which had been bodged and then put everything back

hc25036

That's what I was worried about!

Thanks guys - will see what the bathroom fitting company says and report back

tpt

posts above are bang on. if the tiles have been laid straight onto floorboards or chipboard then thats your problem. floor should have been overlaid with backerboard or ply at the very least.

you should be able to tell (sort of) by how much of a step you have going into the bathroom. ply should raise it by 20mm (plus tiles) and backerboard by 6mm

hc25036

The job spec said board floor with plyboard to prepare for tiles, but I don't think the floor level has raised by much at all.

The install was not cheap, so I'm very interested to see what reply I get from the installers....

hc25036

Just a thought - what excuses might be used to avoid fixing the job and what are the answers?

My contribution - it's the joists and not our fault (answer - you should have made sure it was sound before laying the tiles).

Any more?

MX5huggy

What adhesive was used it should have been a flexible one.

tpt

flexi adhesive wont stop cracking. it just stops the tiles lifting. any deflection in the floor needs to be stopped first and then a flexi adhesive used.

if they have quoted to prepare the subfloor then there isnt an excuse. they should have used at least 12mm (pref 18mm) ply over the floorboards and this should have been screwed down every 200-300mm. this is a ball-ache and easy to cut corners on.

if they have used backer-board then it should be within manufacturers specs.

you'll find some part of this hasnt been done - my bet is on no ply at all or 6mm ply has been used.