Dot n dab - PVA or not

[FredFlintstone]

Now forgive me if this is a stupid question but I can't decide what to do.

I've removed all the old plaster from the kitchen / dining room because it was shot in about two thirds of the room.

It was incredibly sandy and crumbly (obviously because it's shot) and left a fair few patches on the wall which I've scraped off with an old cheap trowel. I've also brushed the wall down but the bricks are still a bit sandy in places.

So, my question is - should I PVS the wall before sticking the boards up?

I've never PVA'd before when dotting and dabbing and I've never had any problem with the adhesive not adhering. Having said that - I've never used drywall adhesive on a wall that's been previously plastered and stripped.

I'm of the thinking (and hoping - because it's a lot of wall to PVA) that if anything, a dose of PVS will prevent the adhesive bonding to the wall so well. Even though the bricks are a bit sandy the adhesive may still hold to the bricks.

Any thoughts?

Cheers.

Fred.

 

[perks1611]

I would dilute pva with water, about 4-1 and roller it on as its quicker, when dry it will be hard and wont be sandy at all. Ideal for dot and dab.
I've had to do this in a older house myself and its fine. On sound walls you dont have to.

What you dont want is the adhesive to come away from the wall after its gone off and you ve just board out most of the room!
Good luck

 

[masona]

See what the instruction say on the drywall adhesive, my properties was built in 1902 and dot n dab my kitchen on the bare brickwork, all I did was hose down the dusts water to clean it, never has any problem with it since 9 yrs.

 

[FredFlintstone]

I would dilute pva with water, about 4-1 and roller it on as its quicker, when dry it will be hard and wont be sandy at all. Ideal for dot and dab.
I've had to do this in a older house myself and its fine. On sound walls you dont have to.

What you dont want is the adhesive to come away from the wall after its gone off and you ve just board out most of the room!
Good luck

Cheers Perks,

Like I say, I've never PVA'd before when using adhesive and have never had a problem. The way I see it is that PVA is to reduce the porosity of the wall so it doesn't suck all the water out the plaster too quickly thus causing cracking. With adhesive this isn't an issue.

What worries me is that if the PVA film prevents the adhesive actually sticking to the wall so the boards are only adhered to a thin film of glue. Unlikely I suppose and as you suggest, a weakish solution shouldn't cause such a problem - it'll just help seal the bricks.

Masona, I've got nice big trade bags of adhesive and I don't think there's any instructions. Might check the British Gypsum website actually - that's an idea.

I'd considered washing the walls down but it's a big hassle drying them and floor out - the room's not heated at the moment and is also very draughty due to me not having sealed the cavity up yet where I cut the wall out for french doors.

 

[Thermo]

id just wet the wall down and not pva it. the suction into the brickwork will be much better than it will with a coat of pva.

 

[noseall]

we use a garden hose with a Hozelok shower spray attachment, when damping walls down prior to dabbing or floating. neat water is perfect for the job.