tiling on to plywood

[natnat]

Hi

I recently tiled a bathroom which was boarded out on the stud walls with 12mm wbp(origin china).It was a ceramic tile approx 400mmx250mm.
Ply was primed with acrylic primer then tiles fixed with a good quality single part flexible adhesive.

Floor was joists @ 400mm centres.22mm Chipboard overboarded with 12mm wbp(china origin). tiles are porcelain 300mmx300mm.

All have come away completely from plywood.

I have been using these methods for years with no problems.

Anyone got any input on what the cause could be for this major failure.

 

[White Room]

Hi and welcome.....some very low grade ply has been coming over from china, which your post proves the point...no easy way round this but to rip up.

 

[Ian]

What adhesive was used? Some manufactures specify not to prime the face before application.

 

[White Room]

Read it wrong, after having another read thought the ply was separating from itself....

 

[Dan]

Welcome to the forum. Sorry to hear about your problem that sounds expensive.

 

[natnat]

this manufacturer specifies to prime first

 

[White Room]

Is this the first time you have used this brand of ply for this job...

 

[natnat]

yes it is whitebeam

 

[ruairi mac]

Has adhesive stuck to either the plywood or the tile??

 

[White Room]

Has the ply any delamination or swelling on the surface..

 

[natnat]

small amount on ply,mostly stuck to tile though.tiles have come away in complete panels almost.there doesn't appear to be delamination or swelling

 

[White Room]

What primer and adhesive did you use....

 

[ruairi mac]

I had originally thought it would be a movement issue with the ply, but if that was the case I would have expected the adhesive to be mainly stuck to ply and the tiles to have been clean.

What your'e describing, to me, suggests an issue with the primer. As long as the adhesive has stuck to one surface you an be pretty sure the adhesive isn't at fault.

Was the primer a new bottle or did you have it lying around for a while?
Did you mix it or apply it neat?
Did you stick tiles while primer was still tacky?

 

[Brendan25]

i would start a over and use
[h=4]Weather & Boil Proof (WBP)[/h]This is what most people usually mean when they say "marine ply". It is a high quality ply suitable for outdoor applications. As its name suggests it will remain waterproof, and won't blister or de-laminate even if soaked and then left to dry in the sun. Unlike marine ply it may have small voids, and is not suited to constant immersion, but is cheaper. Finish is usually nice and uniform (if a little plain) with no visible knots in the outer surfaces. then tank it with bal water proofing kit and go from there i hope this helps...

 

[Neally]

Are you sure its not the back side and edges of the ply prior to the ply being fixed ? If all is fine then Im sure the adhesive manufacturer will help identify the failure.............

 

[PHG Dave]

i would start a over and use
Weather & Boil Proof (WBP)

This is what most people usually mean when they say "marine ply". It is a high quality ply suitable for outdoor applications. As its name suggests it will remain waterproof, and won't blister or de-laminate even if soaked and then left to dry in the sun. Unlike marine ply it may have small voids, and is not suited to constant immersion, but is cheaper. Finish is usually nice and uniform (if a little plain) with no visible knots in the outer surfaces. then tank it with bal water proofing kit and go from there i hope this helps...

WBP plywood, even the best quality, is NOT waterproof.
Also there is too much chance of coming across substandard ply stamped as WBP grade that will delaminate if any moisture gets to it.
Plywood should not be used as wallboards to tile onto, use either a cement based tile backer board which would be water resistant, or Marmox boards which are waterproof