Sealing very absorbent walls

[User1234567890]

I have banged off back to the brick, and am dot and dabbing 12.5mm boards on. I PVAd the wall with a 5 to 1 mix and then again with a slightly stronger mix, but the walls are still super absorbent and it is sucking the moisture from the adhesive and the boards are not sticking properly.

As PVA isn't having the desired effect, do you reckon it's worth getting something else? I tried Gardz on a section of the wall and it seems better, but it is still really absorbent, so would work out expensive to do all of it like that. SBR looks like it would be OK, but that's also quite expensive. Just want to make sure I'm getting the right thing. Thanks.

 

[foxhole]

Use fixing foam adhesive .

 

[opps]

You can get SBR for about £20 incl delivery. It is more expensive than PVA, but I wouldn't call it expensive. I guess it is all relative though.

I have only done dot and dab once. I haven't tried the expanding foam though. If you use it, spray both surfaces, it aids both adhesion and curing.

 

[opps]

You can get SBR for about £20 incl delivery. It is more expensive than PVA, but I wouldn't call it expensive. I guess it is all relative though.

I have only done dot and dab once. I haven't tried the expanding foam though. If you use it, spray both surfaces, it aids both adhesion and curing.

Edit- sorry, I meant to say both surfaces with water

 

[User1234567890]

Thanks, I thought I'd replied to this, sorry. I bought some SBR and that has done the trick, brilliant stuff. The boards are going to be fixed in place with a mix of battens and adhesive. I may go for the foam as it's a real pain mixing up a big bucket of the plasterboard adhesive on this stairwell as there's not a lot of room to do it. Does anyone know of a foam adhesive that will stick to the boards when they are upright, without falling off? It's not possible to lay the boards down to do this and I'm working alone, so don't want to be lugging the boards up and down the stairs to foam them, if possible. Cheers.