hi

as a lot of tilers on tf arnt a fan of tiling directly on to ply, then i thought i'd post a little guide line so people can decide on how they would like to deal with it..

feel free to add anything i have missed..

WBP Ply: (Weather & boil proof)

Ply wood can be very problematic due to issues such as: water ingression, deflection, rot, fungal issues and poor quality Asian imports containing high quantities of thermaldhyde glue.
If possible, use an uncoupling membrane to compensate for lateral expansion or overboard using a backer board to provide a stable & water resistant surface on which to tile upon. If however you tile straight onto the ply without a de-coupling membrane, then check for deflection and use a 2 part flexible adhesive.

British standards is 15mm
Ply comes in 6mm, 9mm, 12.5mm, 15mm , 18mm and 25mm depths.
Sheets are approx 1.2m x 2.4m. (smaller dimensions can be obtained)
Prime the back and the sides of the ply and allow drying before installing.
Check your adhesive manufactures guide lines as some say ‘prime the face of the ply too!
Screw down at 150mm to 225m centre’s using corrosive resistant screws (brass, s/steel etc)
Stagger the boards when laying, leave a 10mm gap around the surface area for expansion, and allow a 2mm gap between each board for deflection. Fill this gap with a flexible adhesive and a alkaline resistant tape.

well said Ed

Great post Aston

Top post from a Tilers forums elite member.

I'm going to start avoiding ply !!!!
hate tiling on it now,i have started pasting it with a skin of adhesive the day before i tile it and it seems to be working really well.

Originally Posted by AstonTiling

hi

as a lot of tilers on tf arnt a fan of tiling directly on to ply, then i thought i'd post a little guide line so people can decide on how they would like to deal with it..

feel free to add anything i have missed..

WBP Ply: (Weather & boil proof)

Ply wood can be very problematic due to issues such as: water ingression, deflection, rot, fungal issues and poor quality Asian imports containing high quantities of thermaldhyde glue.
If possible, use an uncoupling membrane to compensate for lateral expansion or overboard using a backer board to provide a stable & water resistant surface on which to tile upon. If however you tile straight onto the ply without a de-coupling membrane, then check for deflection and use a 2 part flexible adhesive.

British standards is 15mm
Ply comes in 6mm, 9mm, 12.5mm, 15mm , 18mm and 25mm depths.
Sheets are approx 1.2m x 2.4m. (smaller dimensions can be obtained)
Prime the back and the sides of the ply and allow drying before installing.
Check your adhesive manufactures guide lines as some say ‘prime the face of the ply too!
Screw down at 150mm to 225m centre’s using corrosive resistant screws (brass, s/steel etc)
Stagger the boards when laying, leave a 10mm gap around the surface area for expansion, and allow a 2mm gap between each board for deflection. Fill this gap with a flexible adhesive and a alkaline resistant tape.

hi aston great post mate but the only thing i would ad is u dont fill the gaps in the boards u leave for expansion with tile adhesive because this sets solid and leaves no expansion so use something like silicone instead.

hi andy
spf is deformable to 1mm and
there is no recommendations that i am aware of that state 'dont use' adhesive and if the floor is structurally sound (which it should be) then this again will eliminate any issues...your 10 mm perimeter gap also reduces pressure too

if you use silicone then thats a fine too, thanks for the input mate, appreciated..

ed

Yeah! Go Ed!
I think most people on here know my views on tiling onto ply. I think youv pretty much said it all. Its naf stuff to tile.

Good post

Ed is right.. the gap is left as each board will expand differently and the gap stops them pushing against each other causing tile heave( Tenting)..
Filling that gap with adhesive will not harm the installation, but it is wise to strengthen the joint with alkaline resistant seam tape.

Nice post Ed, Thanks for the Info

Top post Ed.........

it would be interesting to know the australian and american tilers view on tiling on ply.

Originally Posted by AstonTiling

it would be interesting to know the australian and american tilers view on tiling on ply.

It would be. Im not sure but I dont think anybody does it as much as we do.
Iv not workd abroad so couldnt say but I have been told that the germans and, most of europe, think that it is a stupid idea.
I would be interested to hear from Jay and Rob on this one.

Originally Posted by hillhead

I'm going to start avoiding ply !!!!
hate tiling on it now,i have started pasting it with a skin of adhesive the day before i tile it and it seems to be working really well.

Not fond it of it myself, but unfortunately in this country it's a builders answer to everything. Wish backer boards were more easily attainable - yet to come across anywhere that sells them.

Originally Posted by Wingn

Not fond it of it myself, but unfortunately in this country it's a builders answer to everything. Wish backer boards were more easily attainable - yet to come across anywhere that sells them.

Really!? Have you asked to see if your supplier can order it in?
I can get Hardie, NMP and aquapanel down here but builders dont like using it it costs money and they always seem to have a load of ply left over that needs using up

Originally Posted by Wingn

Not fond it of it myself, but unfortunately in this country it's a builders answer to everything. Wish backer boards were more easily attainable - yet to come across anywhere that sells them.

have you tried your local Travis Perkins, Wingn, that's where I normally get mine

Originally Posted by Dylante

Really!? Have you asked to see if your supplier can order it in?
I can get Hardie, NMP and aquapanel down here but builders dont like using it it costs money and they always seem to have a load of ply left over that needs using up

Blimey, I know that one, I had a builder build a wall out of shutter ply that he had left over, and nailed it to the wall with clout nails and asked me to tile it, guess my reaction? rotfl, after 5 mins laughing I said no

Originally Posted by doug boardley

have you tried your local Travis Perkins, Wingn, that's where I normally get mine

Don't have the luxury of such a shop in NI. Any builders merchants or tile shop you ask in, their eyes glaze over and look at you with a puzzled expression. Wouldn't mind getting my hands on some locally. What sort of price is it for a sheet? Next JOTM prize should be a pallet of cement boards.

Bad enough getting Ditra over here. Of ten tile shops I rang, 3 didn't know what it was (one asked "Is that the anti crack mat?") , 4 didn't stock it, and 3 had it at varying prices.

the board manufacturers are missing a trick here

its not the use of ply thats a problem these days, its sourcing suitable ply and this is getting harder

whats needed is a tiling overboard, thats light weight , easy to cut and stable enough to take the deflection out of suspended floors, this may have to float on a decoupling membrane

all suspended floors deflect, its designed in to disperse shock and vibration and cement board alone will not stiffen the floor against deflection

Great post, Ed

Following this and recent posts re ply, I would like some advice on the floor of the bathroom I'm currently doing.
Suspended floor, The t+g is in such a state that I'm going to remove it and replace with 25mm ply. I have ufh mat, slc and 8mm porc tiles to go down, I was thinking of 6mm hardi over the 25mm ply, but as it'll be slc'd anyway, I'm not sure of the value of this, can I have some views please?
Many thanks.............

Thats your call mate, you shouldnt have any problems with using a suitable SLC over the ply (of course check that it is ok for ply and UFH). The benefit of over boarding with a backer is that the backer boards are machanically fixed to the ply. As Eds post says, ply is not the best surface to bond to, over boarding eliminates that problem (providing that there is no deflection in the floor).