www.ultimatehandyman.co.uk

Hi, I've been looking for answers to this and have found a lot of conflicting answers!

My question: I'm tiling a shower, and one side of the shower is ply (don't know what type), and the old tiles were stuck fast to it so there's quite a lot of tile adhesive all over it.

Also, I've had to put up some pine battens either side of the door.

The adhesive I'm using says to prime timber with an oil-based primer first.

I'll do this with the battens, but does that also apply to the ply? And if so, does it matter if I prime over the left-on adhesive as well?

Many thanks.

you will either use twice as much adhesive going over old or your finish will not be level!
IMO rip up floor replace with 22 ply primed on both sides and edges theen get a steam stripper on the walls to remove whats left off the old addy! job done right.

It's not a floor, it's a wall, and it goes up behind the coving and down behind the shower tray so it would be a pig to get it out (and plus it's all decorated now bar the tiling).

The existing adhesive is not too uneven so it won't be too bad to even it out.

So the intial question still stands....

Many thanks!

ok! then the answer is PRIME EVERYTHING you are going to stick tiles to!

Cheers, will do.

However, I'm niaive and don't really know what a solvent-based primer is (not oil-based as I originally said)?

Can anyone explain or point me to one?

Many thanks!

what are the tiles ceramic porcelein or what? and what adhesive are you going to use?

I'm having a right pig of a time here. Beginning to doubt myself.

I Tiled 2 walls with ceramics and used B&Qs Cerafix. Noticed a couple of days later that it wasn't really setting so went online and looked it up and found that it's pretty bad stuff. So took it all off (very easily i might add), cleaned the tiles up and the walls and used Dunlop waterproof adhesive instead as per previous work.

However, being curious, I must say that less than 24 hours later (but the next day still), I'm able to pull a tile off clean from the wall. That adhesive isn't setting either. I can easily scrape it from the wall and from the tile. It's still quite soft and powdery.

Will adhesive dry given enough time or has it failed by this point?

To answer your questions, they are ceramic tiles.

Many thanks. Happy easter.

hi andrew
few things mate..
ply as a wall subsrate in a wet area imo is a big no..no..
epsecially ply that has already been tiled.

addy you used b&pee stuff is crap..
addy not setting..how big are your ceramic tiles if they are over 300mm you should be using a bagged adhesive..

imo..i would rip out the ply and reboard with m.r plasterboard then tank wet area with a wall tanking menbrane..homelux/kerdi/dura..etc.
or
12.5mm backerboard..hardie/aquapanel/wedi..etc follow m.i.

primer you should be using(acrylic)
bal..primer/apd or sbr
mapei..primer G
just floow m.i. regarding mix ratio..

if your doing it mate.. do it right with the correct materials and it will last.

tictic,
I noticed andrew mentioned that the ply is up behind the coving and down behind the tray.

Whats your thoughts on cleaning the ply, sand back to get rid of the residue, prime, tank with BAL WP1 or membrane and tile with bagged adhesive as you say.

Regarding the primer, I rang BAL and they suggested to use SBR on ply rather than APD but the suggested that you do it on the reverse side only. I think this is to let any moisture in the board escape rather than upset the tanking and grouting process. For my floor they told me to prime the surface with SBR to aid adhesion. This was ok as I hadn't sealed the underside. I guess it makes sense.

What do you pros think about this?

There is useful information on the BAL website see, the BAL SiteWork guide for a read Click me

DIY_Johnny wrote:tictic,
I noticed andrew mentioned that the ply is up behind the coving and down behind the tray.

Whats your thoughts on cleaning the ply, sand back to get rid of the residue, prime, tank with BAL WP1 or membrane and tile with bagged adhesive as you say.

Regarding the primer, I rang BAL and they suggested to use SBR on ply rather than APD but the suggested that you do it on the reverse side only. I think this is to let any moisture in the board escape rather than upset the tanking and grouting process. For my floor they told me to prime the surface with SBR to aid adhesion. This was ok as I hadn't sealed the underside. I guess it makes sense.

What do you pros think about this?

There is useful information on the BAL website see, the BAL SiteWork guide for a read Click me

hi johnny
in my honest opoinon i would rip the ply out,take tray out and remove coving and replace completely.
and use a better product for wall subsrate.
again ply (already been tiled)..will not have the same strength now..
as for primers..with bal products..
wall prep..with bagged cement based addy..prime with primer/apd or sbr.although sbr is not an acrylic based primer tho..
this prevent any reaction between the gypsum based plaster to the cement in the bagged addy..

for floor prep using wbp ply..
then i would always use sbr on the underside and edges of ply before fixing down,this stops as you say any moisture ingrees from below.also you can use it on the face of ply to,as it helps the bond between the addy and ply to..sticks like a @@@@ to a blanket..

other manufactuers will also tell you when using their bagged addy to prime the SURFACE of the ply to(for floors)..mapei/weber/ardex ect
always read and follow m.i.

re:wbp ply
there is a lot of cheap inferior ply floating about these days..i dont use wbp ply for overboarding...
backerboards for me,have been for a number of years now..

thanks Tictic, very helpful info, you know your stuff.

I really like BAL SBR, try walk on that the next day. Like walking on celotape

Thanks for detailed replies.