Hi everybody,
Need some more advice.I am laying 600x600 porcelian tiles over 15mm ply.I have been supplied Granfix one part rapid setting ceramic tile adhesive (says suitable for porcelian)and have primered the ply with granfix pva bonding primer.I have laid about 20 tiles and find that most of them have not stuck properly. They have not been walked on and have been left for 48hrs.When you tap them you can tell they are not stuck and are easy to lift up off the floor.The tile cement does not seem to have adhered to the back of the tile at all ie they lift up and have very little adhesive on the back.I just mixed enough to do a couple of tiles at a time so I dont think the adhesive had gone off before i put each tile down ie it was still fairly wet.They are not cheap tiles.Am I doing something wrong or is there a problem that I dont know about ? I am a careful diyer and can sort most things , but this is doing my nut in ! any sugestions guys ? I have taken a lot of care to get this floor mirror flat and even wondered if there was a product that i could spray ( ? )some special adhesive that would bond everything together so I dont have to take up every tile , scrape the floor etc . I need a drink

chilllllll....here's that drink>> ...

Did you check the tiles to see if they planertise..?

And..where did you get 15mm ply from....?...coz it's not available in the uk is it..?

Originally Posted by Dave

And..where did you get 15mm ply from....?...coz it's not available in the uk is it..?

It is but its not common.

I've never seen any......

15mm Far Eastern Ply | Far Eastern Plywood Fast Nationwide Delivery

Timber sales in Southampton and surrounding areas.

Far eastern..........ok imported then...

Originally Posted by Dave

Far eastern..........ok imported then...

What isnt these days ?
I cant see the sense in hunting for 15mm anyway, i use 18mm or if i really had to 12mm.

Its all 12mm then jumps to 18mm ply round here, North East, ive never ever used 15mm before, personally i would have used a full multi flex adhesive (spf) or porcelbond adhesive, not a ceramic adhesive that may be suitable for porcelain
Try out one of the flexi adhesives and see if that works

I have never seen 15mm in a timber merchants...online maybe...but not in jewsons etc...

12mm is fine IMO...in the right situation..

Same here, i would advise 12mm on tounge and groove, screwed down every 300mm centres or possible 9 mm on weyrock

Originally Posted by Dave

I have never seen 15mm in a timber merchants...online maybe...but not in jewsons etc...

12mm is fine IMO...in the right situation..

Originally Posted by NETT Darren

Same here, i would advise 12mm on tounge and groove, screwed down every 300mm centres or possible 9 mm on weyrock

What are you guy's thoughts on this 6mm hardie debate about it being sufficiently strong to add strength to a deflecting floor?

anyway, back to adamoliv...... what sort of trowel did you use mate? you say that there's no addy on the tiles, imo you should have used a 10mm solid bed trowel if your floor was pan flat

For that size of tile I would have defo been back buttering the tiles as well as the addy on the floor.

Originally Posted by grumpygrouter

What are you guy's thoughts on this 6mm hardie debate about it being sufficiently strong to add strength to a deflecting floor?

Put it this way russ...if your sub-floor is ok the mapei say you can use their adhesives no probs........

name any other brand that sez that..?

having re-read your post adamoliv, is there a chance that the back of the tiles may be dust contaminated?

Sorry , dont know that.What is planertise?

thanks , I`ll try anything !

Yes I did ,10mm round notched.When I lift a tile up there is the imprint of the full tile on the top of the addy, so I feel the tiles sat on the addy ok and level ,the addy is squashed a bit but there is no transfer to the tile.The addy was definately wet and I did push em down a bit to make sure of a bond.

Dust on the back of the tiles sounds like the likely answer.

Thanks Fekin, but I have just rechecked 3 boxes of tiles ,6in a box,and they are all clean , no dust at all. Is this granfix stuff meant to be good in the industry? Is painting the back of the tiles with pva an answer ?