Hi, I have put floor tiles onto my kitchen floor. Old chipboard was left - I didn't plywood it. Put down a 6mm stiff foam layer for thermal properties. I didn't adhere the foam layer to the chipboard.

This probably reads like a catalogue of errors - my apologies in advance - most of the floor is ok - but in a few square metres the grout is breaking up. There is a small amount of movement between the tiles in these areas.

I'm looking for advice on a scale of difficulty. The most work being a complete lift and relay using plywood. However, I wondered if there was some type of really flexible grout that I could try out before going to the lift and relay stage.

The current grout is Mapei Ultracolour Plus

kind regards

jullhoogi

You don't say how many m2 there is on the whole floor, There's a good chance that the rest of the floor may follow suit with the cracking. If you change the grout it will a totally different shade, I personaly would rip up and start again IMO

about 5m2 but the whole chipboard floor would have to come up - it's in the kitchen - so the kitchen units might have to come out too. Seems like a big job .

Can't you over board the chipboard with ply then tile, Just worth checking the hight for washing machine and the like

Thanks whitebeam - that would definately save some time. I'm guessing that the existing tiles would be unuseable due to adhesive on the bottom? Would there be any point in reusing them?

Not really, The cement adhesive would impossible to get off, Just go for a new colour scheme

Thanks whitebeam - just to double check - when grout says it is flexible - this is relative - e.g. it won't deal with 0.5mm movement between two tiles vertically.

0.5 is tight for any jount, Should be looking at 3mm, And yes when it say flexible it should be within reason, If the floor doubles as trampoline, No, floor must still be rigid

Sorry for the confusion - the joints are 4mm width - but between a couple of the tiles with movement - there is movement of 0.5mm. I wondered if I was to use a stronger grout (I think i mixed too much water when making up the Ultracolour Plus, which may have weakened it) then it would hold the slight movement and stop cracking appearing in the grout.

Thats due to the foam layer thats on the floor that has'nt been fixed thats why cracking is accuring, If you replace with a stronger grout it won't make any difference. If you want a quick fix try the mapei silicone to match the colour you already have in the joints but maybe a short time solver, But worth a try if the cracking is in a small area. Remove existing grout before applying the silicone

many thanks whitebeam

I forgot to ask if it is feasible to tile on top of the existing tiles. I am assuming that any movement will be less, when tiles are tiled on top of existing tiles that have a slight movement.

No, It would'nt make the situation any better, Your foam layer is not fixed it may at a later you would be removing two layers of tiles rather than one

ok - thanks again whitebeam.

Sounds like a job for ditra.
But first rip out the mess you already have in place.
Expose the chipboard and install ditra then tiles.

Or you could take out the chip board (providing it has another layer under it) using a skill saw a prybar and a chisel.
I have done this many times as it is the only solution in many cases.
If you are not raising a sweat then you are not a tile setter.
Don't be scared of a bit of hard work.
If you want a warm floor you could look into the electrical heating mats which can be installed under the tiles.

I have a very similar problem, and I really do not want to refit the kitchen.

It did not happen before, but I can not remember what was on the floor before, but it was probably lino.

Is there any chance the Washing Machine maybe too "active"? Can it be dampened, by putting something between it and the floor? Are there any "quieter" Washing Machines around?

I did the kitchen and bathroom, using the same adhesive and grout, and the bathroom is fine. I ave had enough of it now, and need to sort it out!!!!!