grout cracking

[jase158]

Used 6mm ply,
flexible adhesive
flexible grout

yet the grout is cracking

any help please..

 

[DHTiling]

6mm ply is the clue 🙂

 

[jase158]

i have seen this used before and it was fine!!

 

[DHTiling]

It is still wrong though... and hence what has happened..

 

[Brian the Tile]

6mm ply is no good to thin you might as well have put cardboard down sorry not being funny about it just truthfull,you would need 10 mm minimum and screwed not nailed every 100mm then sealed first before tiling

 

[jase158]

sealed with what?

 

[peteablard]

15mm minimum.....

 

[Brian the Tile]

ask at the shop where you get your adhesive at you can not tile strait onto the ply without it being primed first they will give you the right one for the job ,if you dont do it your tiles will fail again

 

[jase158]

they told me the adhesive could go onto anything, wood, plasterboard or screed

 

[Ian]

Some adhesive manufacturers say to prime the rear and sides of ply, not the face. That aside, use cement boards and the job will be a better one all round.

 

[jase158]

Some adhesive manufacturers say to prime the rear and sides of ply, not the face. That aside, use cement boards and the job will be a better one all round.

where would i get cement board and what size should i get?

 

[Brian the Tile]

what adhesive have you used ?

 

[kilty55]

6mm ply is the issue here i would think

 

[Ian]

where would i get cement board and what size should i get?

Most reputable tile shops stock them and a lot of builders merchants as well, two sizes that I know of, 1200x800 and 1500x900mm.

 

[kilty55]

6mm thick ones for the floors

 

[jase158]

20KG RONNIE SLOW SET FLEXI WHITE ADHESIVE

5mm gaps

MAXIGROUT HYGIENIC IVORY 5KG GRANFIX

 

[Ian]

LOL, yeah 6mm thick, I'm being a bit dumb! Have a look at this thread, may come in handy for you http://www.tilersforums.com/tiling-forum/58805-installation-hardiebacker-250-500-a.html

 

[jase158]

6mm thick ones for the floors

cheers,

Is that screwed?

 

[White Room]

Yes, I use 25mm gold screws from Screwfix for the Hardie Backer boards.

 

[bugs183]

"Ronnie' (Cray,Biggs??)adhesive!

 

[bugs183]

Sorry mate, just pulling your leg.
There are all kindsa ways people fix these boards, but the best way is prime the floor, trowel adhesive at 6mm press the boards into this and then screw down whilst wet. The floor will be lovely and solid then.
Sorry the joints a re cracking, but tiles don't like being laid direct to plywood, especially when its that thin.

 

[jase158]

also the problem is that the plywood is under a couple units

 

[jase158]

could I pull tiles up, put cement board down and then tile on top?

or should I pull the 6mm ply up?

 

[White Room]

I'd be pulling the ply up......

 

[Ian]

I'd be pulling the ply up......

I agree, get back down to the floor boards/chipboard and start afresh.

 

[jase158]

thank you to everyone for your help, costly mistake, but will have to be fixed. doh

 

[bugs183]

Trouble is it's not a mistake you've made by being daft.
It's so widely done, everyone believes it's fine to go straight onto thin plywood, not all of these floors crack, so people still do it.
It's taken a while for people to actually rethink how to tile onto wooden floors.
So your not the only one!!

 

[jase158]

Trouble is it's not a mistake you've made by being daft.
It's so widely done, everyone believes it's fine to go straight onto thin plywood, not all of these floors crack, so people still do it.
It's taken a while for people to actually rethink how to tile onto wooden floors.
So your not the only one!!

cheers, thats made me feel a bit better about it, will learn for next time

 

[Martino]

Jase158 - possible failure could also be, not enough addative in the adhesive or grout also leave gaps between your ply, cement boards are more expensive so you cant use them on every job!...well not where i live anyway...you wouldnt get any work basically someone would be cheaper!....i have and still do use ply and belive you still can, a lot of people on here will dissagree with me but what did we use before backer/cement board?.....plywood. 🙂....i firmly belive if applied correctly it can still do the job!

 

[peteablard]

Jase158 - possible failure could also be, not enough addative in the adhesive or grout also leave gaps between your ply, cement boards are more expensive so you cant use them on every job!...well not where i live anyway...you wouldnt get any work basically someone would be cheaper!....i have and still do use ply and belive you still can, a lot of people on here will dissagree with me but what did we use before backer/cement board?.....plywood. 🙂....i firmly belive if applied correctly it can still do the job!

Ply isn't the issue it's the thickness of ply used that's the problem!

 

[Andrew Case]

I think it's nice and encouraging to see someone putting a job right rather than running or leaving it as is! I don't know if this is your house or a customers but either way it would have been easier to leave it, but youve asked the questions and are putting it right. Good for you.