Cracking Floor Grout !!!!!!!!!!!!!!!!!!

[Kenny C]

The adhesive was powder mix fully flexible. Quote from Daywalker

Hi Guys

I am just about to start my floor ( DIY ) with a natural stone the inter locking sort with a mesh back pretty expensive so I dont want to mess up,after reading about 6mm & 12mm ply and cracking grout got me worried. I have used 6mm ply screwed down every 6inch square on to new floor boards which are on top of new joists. does anyone have any sugestions regards to adhesive and what do you think regarding my ply 6mm, does fully flexible adhesive mean fully flexible even when dry? Sorry if any of this sounds silly but tiling is a new string to my DIY bow.
Cheers Kenny

 

[MICK the Tiler]

Hi all, grouted a bathroom floor this morning using Granfix Ultimateflex floor grout no problems, tiles spaced using 5 mm spacers, timber floor with 9 mm ply over lay, no under floor heating.
2 hours later found hair line cracks down the centre of every grout line :huh2:

Any one else had this happen and whats caused it ????????????.

How long did you leave the floor tiles to dry before grouting?


Please guys don't use pva for admix use a proper admix for grouts and glues pva is not designed for use with cement based products and you will gain no advantage in doing so.

Using pva in your adhesives and grouts will cause the pva to be slowly attacked by alkali, forming acetic acid as a hydrolysis product. not something you want in a grout or adhesive as they will slowly break down as a result.

Please refrain from using pva as an admix PLEASE!!!!!

 

[shamrock72]

the pva i use is ardion 90.. expensive but very good never had any problems...

 

[MICK the Tiler]

Remember though ardion 90 is only an admix for cement based adhesives only not an admix for grouts.

And it must not be used as a primer.

 

[grumpygrouter]

the pva i use is ardion 90.. expensive but very good never had any problems...

is it definatley PVA? Would have thought it might have been an acrylic admix. I use the E101 with ardex grouts and I am pretty sure that it is acrylic and not PVA.

Grumpy

 

[Daywalker]

What tiles were they and what size?

Kev

Hi Kev the tiles were porcelien ones 300 x 300.
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Did you put PVA in the grout mix. You don't need a lot but it does help.

Hiu grout pad, you dont need any mix with this granfix grout its fully flexible, cheers.
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Hi Mick the tiles were left over night to set on full fleximate adhesive, cheers.
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Hi all thanks for your feed back on this i'm thinking may be the grout was to wet but at the time had a good paste like consistancy for a powder mix.
I mixed three separate mixes as you have a short working time 30-40 min upon conditions and the whole floor is the same ( 10 sq m ).
I,ve used Bal floor grout with admix etc no probs.
Like i,ve said before you do not add any P V A or ADMIX with this flexi floor grout
so not looking forward to redoing the floor but what the hell its gotta be done
see what the rep has to say about it.

Will let you know of the out come fo this. Mark.

 

[MICK the Tiler]

is it definatley PVA? Would have thought it might have been an acrylic admix. I use the E101 with ardex grouts and I am pretty sure that it is acrylic and not PVA.

Grumpy

Hi Grumpy,

Nothing in the tech sheet suggests it is a PVA (Polyvinyl Acetate) or isn't for that matter, but I doubt it would be a true PVA maybe a derivitive of it as a true PVA would not be a good partner to a cementuous adhesive due to the fact that it will break down in the presence of alkaline salts to form acetic acid, not something you'd want under your ceramics or stone.

As a test maybe I should try and build a coffee table, glueing it together with Ardion 90. Not sure how that would turn out.

 

[grumpygrouter]

Hi Grumpy,

Nothing in the tech sheet suggests it is a PVA (Polyvinyl Acetate) or isn't for that matter, but I doubt it would be a true PVA maybe a derivitive of it as a true PVA would not be a good partner to a cementuous adhesive due to the fact that it will break down in the presence of alkaline salts to form acetic acid, not something you'd want under your ceramics or stone.

As a test maybe I should try and build a coffee table, glueing it together with Ardion 90. Not sure how that would turn out.

LOL!

Grumpy

 

[DHTiling]

Another option as to why it could have happened is with this being a timber floor once grouted no one should walk on the floor for at least 12 hrs . this gives the grout time to dry and form a solid key the tile edges...walking on a timber floor could result in slight movement and cause cracking....just a thought......always let it set before letting anyone walk on it........

 

[Daywalker]

Another option as to why it could have happened is with this being a timber floor once grouted no one should walk on the floor for at least 12 hrs . this gives the grout time to dry and form a solid key the tile edges...walking on a timber floor could result in slight movement and cause cracking....just a thought......always let it set before letting anyone walk on it........

Hi Dave, thanks for reply but i,ve not had this happen to me before, evey grout line has a hair line crack up the centres even up to walls etc i.ve changed from Bal to Granfix products the start of the year saving me some money so far, not now!!!
The grout was powder mix full flex same as tile addy, as soon as we looked in the bathroom you could see the cracks etc before we entered the room.