External 12mm No More Ply - SBR or Tank

[tododo]

Hi all
Ive got some 12mm No More Ply to put on a very small retaining wall in the garden. Ive put plastic battens up and plan on using no more ply and then tile onto that. I have put two coats of watered down SBR on all sides of the NMP but is that enough do you think. It will get wet at times is my guess so just wondering if I should go full hog and tank the lot too.....Ive bought the tanking kit (I can return though) but I maybe being paranoid too......or is SBR enough?

Thanks

 

[yorksbuilder]

SBR will be enough. The NMP is waterproof already

 

[tododo]

Brill thanks - felt like I maybe going over the top a touch, but wanted to check...the NMP has got wet before priming and It appeared to soak up water. Now its been primed its far better but wernt sure if I should waterproof more....thanks

 

[yorksbuilder]

It will soak a bit of water naturally.
Your enemy will be frost in the exterior tiles. Hope they last long for you

 

[tododo]

Yeh - they should be fairly sheltered and going for natural stone (quartzite) so should be pretty tough. Im planning to use an S2 adhesive. But Ill be honest not sure if S1 or S2 will suffice. They wont move but there will be some expansion I suppose when in direct sunlight. The place where Im getting the stone from from say S1 is fine and thats all they sell too so again I maybe going over the top .....not sure....the S2 adhesive is quite a bit more expensive too