Hi guys, looking for advice. Last week i tiled a timber floor (overplyed) with ceramic tiles. After 2 days i noticed the grout was cracking. There is very slight movement on the floor possibly 1 to 1.5mm when walking on it.On inspection of the use by date on the grout it was well out of date.I now need to grout again but i am worried because of the movemennt the same will happen again.So just how flexible is grout? It is only a small area and i am seriously considering using sillicone to grout with because of flexibility. Any thoughts please!

it's the movement/deflection of the floor that's caused the grout to crack, and the grout being out of date doesn't help either.

you need to rectify the deflection in the floor otherwise if you just re-grout, it's likely to crack again when the floor is walked on. safest way to rectify the floor is to pull the whole thing up and start again.

what thickness of ply did you use for overboarding the timber floor?

I'm with GRR on this. 1.5mm is a lot of movement really for a rigid product like a tile to put up with. Need to sort it I'm afraid.

You need to rectify the deflection in the floor. What thickness of ply and what adhesive and grout were used on the job. If you have that much movement in the floor, the tiles will eventually crack and debond from the floor.

used 15mm ply but the floor has been previously tiled with mosaics and grout cracking was never a prob with them.Ihave used an adhesive suitable for timber floors.The tiles are currently being walked on and are not cracking at all. Idid notice when i raked out the cracking grout that it came out very easily (very powder like)

"adhesive suitable for timber floors" ??

Would this be a tubbed adhesive like this

Yes very similar but did not use it for grout because i needed a limestone colour grout

Originally Posted by G Hurrell

Yes very similar but did not use it for grout because i needed a limestone colour grout

so you used a tubbed/ready mixed adhesive to lay the tiles?

Yes, bought from homebase, but says on tub suitable for timber floors. Would not use it again!

are you sure that the floor adhesive is set?

Hmmm, tubbed adhesive on a floor is a disaster waiting to happen I think! Being a dispersion adhesive it will probably take quite a while to dry out (if at all depending on the size and type of tile!). I may be wrong here but in my experience it is usually the grout that cracks first when there is movement and then the tiles a while after if you haven't addressed the movement issue. Beginning to think a full reinstal is going to be required.

Yes been tiled over a week. Just really need to know the make of a really flexible grout in a limestone/cream colour

Originally Posted by G Hurrell

Yes been tiled over a week. Just really need to know the make of a really flexible grout in a limestone/cream colour

Have you tried taking a floor tile up then? My downstairs WC was tiled with tubbed adhesive straight on to a concrete floor. When I ripped out the tiles, they came up in sheets/rows and the adhesive hadn't even connected to the floor. I'm sorry to say but no amount of flexible grout is going to stop the cracking of either the grout or eventually the tiles. You have movement issues with your wooden floor and flexible grout will not stop that.

as above, the deflection needs to be sorted and tubbed floor adhesive is pants.......but in answer to your question the most flexable grout ive used is bal wide joint with GT1 admix.