Grout cracking within minutes of applying - TilersForums.com

[StevieG]

Help! I have recently laid tiles onto a wooden bathroom floor with no real problems. Came to the grouting and problems began. Basically, my grout cracks soon after application and I do not know why! For reference, I am using Unibond Tile on Floors Waterproof Grout. The tub says it is ok for wide joints and is flexible.
Can anyone help - am I using the right stuff, or what am I doing wrong????

 

[marc1106]

:welcome:StevieG
if its cracking when you move then it means the subfloor must be moving(big trouble)
or it could just be shrinkage cracks,
are you loading enough grout into the joints?
personally i avoid any unibond tiling products as i beleive theyre substandard
how did you prep the floorboards and what type of boards are they chipboard, t&g?

 

[StevieG]

Thanks for the prompt response.

The floor is stable! It's chipboard flooring - would that make a difference to the grout?

I am pretty sure that I put enough into the cracks. Just called Unibond helpline and they said it was because I was over wetting the grout when wiping clean! If it's shrinkage cracks - how do I overcome them?? What grout do you recommend?

 

[Deleted member 9966]

StevieG

Put a small glass of water on the bathroom floor, and then stand on the floor and bounce up and down. If the water moves, then the floor is moving.

How thick is the chipboard you have tiled on to? And are you sure all the tiles are stuck completely? When did you you tile?

 

[marc1106]

Thanks for the prompt response.

The floor is stable! It's chipboard flooring - would that make a difference to the grout?

I am pretty sure that I put enough into the cracks. Just called Unibond helpline and they said it was because I was over wetting the grout when wiping clean! If it's shrinkage cracks - how do I overcome them?? What grout do you recommend?

ok not teaching you to suck eggs( take no offence) , but is it a new floor, is it screwed down @200mm centers max? did it have any bounce or deflection when walked on before tilig?

 

[StevieG]

After jumping like a looney :lol:, the water doesn't move. Think that means that the floor is stable - phew!:hurray:

Not sure regarding thickness of chipboard as it was already laid (we only moved in 5 weeks ago). All tiles are firmly fixed - laid the last one on Sunday p.m.

I grouted first time on Monday. Took it all out again yesterday as thought it may be due to me walking (only to move around to grout) causing cracking. Did small gap last night and left room straight away. No one entered room to can't be due to walking. Checked this morning and cracks had appeared!

 

[Deleted member 9966]

if it were me (and believe me, i've been seduced by the unibond ready mixed grouts and adhesives in the past), i'd chuck the unibond stuff and get down to your local Tile Giant and ask for a bag of powdered grout that you have to mix yourself. if you don't have a Tile Giant, try B&Q and look for a range called Buildfix.

unfortunately I'm not a pro tiler so I can't explain why the grout cracks once it's dried out.

GRR

 

[grumpygrouter]

What adhesive did you use to stick the tiles?

 

[beanz]

I've only ever seen grout crack that quickly due to movement. On another note, is the Grout Flexible? If it's not, that's your problem imho.

*edit* Not that i have a wealth of experience under my belt (been tiling less than a year).

 

[marc1106]

used the ready mixe grout and addy once on mosiacs and had to grout it 3 times before i was happy, for some reason it always shrinks back, ust get a decent powdered flexi gout, out of interest what sizes are your joints?
Ps glad to hear the floor is stable!