This maybe the longest post I’ve ever made
sorry it seems a bit direct but you have posed so many questions & I have answered them with one liners. If you can fill in the gaps where I asked specific questions, we can take it from there.
The tiles in each room have been placed on top of single sheet 24mm plywood
What sort of plywood, WBP? Was it an overboard or fixed direct to the joists? How was it fixed down? Was the underside acrylic primed? Was any primer use on the tile surface? What size/type are the tiles?
I believe that there is no movement of this as the bathrooms are all small so not possible there is flex.
Well something is isn’t right or the grout wouldn’t have cracked; it doesn’t take much movement to cause problems. It’s the size/pitch/span of the joists that dictates how rigid the floor will be not necessarily the size of the room; do you know if the joist span wall to wall (i.e. is there a support wall below) or do they go under the walls.
One of the bathroom floors is already showing grout cracking in the middle of the floor. As the carpets have yet to go in, I can see from the side that the grout has not been pushed into the crevice/spacing between the tiles
The grout should be full depth.
My major worry is that the problem extends to the other two bathrooms and the wall tiles!
Walls don’t present as many problems as suspended floors; what sort of tiles are they, what is the tile base & what addy/grout was used?
Can the tiles be 'repaired' and made good to last for 5 years or more?
5 years; the job should last at least 10 & up to 20 years if it’s correctly done.
What repair methods can be used - should all the grout be torn out and replaced? Is it that hard to fill the space between tiles? Can I save the tiles?
The grout can be raked out (time consuming) & the tiles re-grouted but weather or not that will cure the problem depends what’s causing it; if the floor is flexing, it will just crack again. Removing the tiles will most likely damage a high proportion if the adhesive has been used correctly.
I now have doubts over the competence of the builder although he came with recommendations.
Recommendations for what sort of work though?
Is the art of getting the grout mix very difficult
Not really & not at all for a tiler.
as you can see from my album, grout used around the bath also is cracking?
You should never use grout around a bath, shower tray, it will always crack; quality sanitary silicone only. I also silicone adjacent walls in a shower cubicle.
I had thought with a bullet proof surface, the tiling should be straightforward.
What is the bullet proof surface that’s been used, not ply I hope? Whilst ply if fine for floors (wet rooms must be tanked), it’s not suitable for walls, infill around a bath or bath panels.
Lastly, what is the standard warranty that a tiler should be giving - he is offering to fix free of charge for up to a year.
A year from the last free fix? If it keeps failing then what? The thing he may make a play on is the fact that you supplied the tiling materials which may not be ideal, why did you not let his tiler do it?
I've spent £10k+ giving him his first chance
What does that mean exactly, is this his first bathroom/tile job?
Should not the grout completely fill the spaces between tiles?
Yes
My major worry is that all three bathrooms show gaps between the plywood and the tiles which are unfilled with grout. Is it very hard to squeeze it in completely?
Do you mean there are gaps between the underside of the tiles & the floor or just between the tiles? Suspended floors must have 100% (or as hear as damn it) adhesive coverage & to achieve this ether a large format trowel (tiles over 300 x 300) or a solid thick bed trowel must be used or sufficient coverage won’t be achieved; voids & gaps will lead to tile flexing cracking the grout lines & even the tiles. Do you know what (notch size) trowel was used? A good guide would be how many sq/m of tiles was laid on the floor & how much adhesive was used?
Is cleaning out the grout from the laid tiles a do-able job - I'd rather he did that so he can refill all the gaps properly rather than fixing the issues in the future.
Raking out the grout is possible but is time consuming & the tiles can be easily damaged with ham fisted use if the rake; thin grout lines makes it more difficult. You might also consider the colour of grout you picked; I advise never to use white on floors, it will look pretty grubby in a short space of time; ivory will be a little better but not much.
The grout was Bal MicroFlex (for joints up to 5mm) which I bought myself. The adhesive was Bal CTF4 White. At least these are what I left in the house for the builders to work with - no reason to believe they didn't use them. Any views on these products?
BAL is high quality & I use it exclusively but it has to be the correct product for the job; I’ve not used CTF4 & it’s a fairly new addition & the spec also requires addition of Admix 1 for additional flexibility when used on suspended timber floors. If Topps specified the addy & failed to advise the use of AD1 then they may have missadvised you if thats wahts caused it, is there any sign of adhesive failure?
I appreciate that many expect a tile shop to know their products & reputable ones should but the manager is exactly that; it's very unlikely he's ever laid a tile let alone been a pro-tiler but he should at least have access to one for advise.
I tried to look at the price (usually a good guide) but I couldn’t find anyone on-line selling the stuff & I can’t even find it on the Topps site either; a little disconcerting, perhaps Topps were pushing it as part of a Promo!
My choice would have been either Rapidset Flexible or Single part Flexible with Superflex grout.
All the tiles were medium to top end price from Topps Tiles. The joints are 2.5mm.
Again, what size/type tiles? Thin grout lines are not ideal for suspended floors especially with large format tiles & you should never go less than 2mm; it may be that Superflex grout will fair better.
The third pic was of the joint between the bath and flat surface tiling between bath and the wall...that grout is also cracking. Because the spacing was longer it is probably closer to 5mm.
As before, more important is what was used as the tile base.
Could it be that the grout mixing was just very bad for the grout in one bathroom? No problems yet in the other two bathrooms although it has only been 3 weeks!!
It’s always possible but very unlikely; BAL gives a comprehensive product warranty but it must be suitable & correctly used; were the same products use in all 3 rooms?
I just want to know what to expect from the builder...I don't want a patch up job if I should be asking him to tear out all the grout and start again.
Difficult to say at the moment but you need to go with a re-grout & see what happens, if it fails again then you might as well rip the lot up & start again. It may be possible to get BAL involved if you’re sure the products have been used correctly but that depends on your answers to all the questions I’ve posed.
