2cm deep battens for securing plasterboard enough?

[User1234567890]

I'm plasterboarding the stairs, and as always in this 1950s build, I banged all the old plaster off back to the brick, and the wall are massively out in all directions, but notably, there's a bulge in the middle, almost all the way up. I was going to use plasterboard adhesive, but to use 12.5mm boards and miss the bulge, I'd be coming off the wall at the top and bottom, anything up to 32mm including the plasterboard. The stairs are also not straight, along the wall, with a large bow inwards in half way up. I can't really come out any further, because of the stair stringers, so 32mm seems to be the sweet spot. That would mean battens of 20mm ish and shorter PB screws.

My question is, would battens of this size, be ok for 12.5mm plasterboard or will there be a problem with it moving etc? Or, should I just use the adhesive and use more of it and the top and bottom? I read somewhere that 20mm and above with adhesive can make it weak? Not starting for a week or so, so probably over thinking it. Any help is much appreciated, cheers.

 

[Wayners]

You can hang a plumb line down and make packers with large cut plasterboard stuck to wall with board adhesive.
You can stack board if needed.

You can also use screws and adjust height to plumb line to level
Have you considered using insulated plasterboard stuck on with foam for final wall boarding?

 

[User1234567890]

Thanks mate, I did it the way you suggested in the hallway on a smaller bit of wall and it worked well, but took me a long time to get the packers right. Used a laser level instead of plumb line, but much quicker to get the boards on after that though.

I've got a load of plasterboard offcuts, so will see if I can do it with those, cheers.