Plasterboard upto a solid wall.

[craig1]

Hi, I'm dividing part of a bedroom by adding a stud wall. I want to position the stud wall to come across level with the fireplace alcove wall. the alcove is 1140mm. The chimney breast is 230 deep where the new stud will start. Just wondering if I can set the stud wall 12.5mm back from the chimney breast so the plasterboard can sit flush with the solid chimney breast and then skim over?

 

[Richard C]

Just wondering if I can set the stud wall 12.5mm back from the chimney breast so the plasterboard can sit flush with the solid chimney breast and then skim over?

Can’t fully visualise the rest of it but that’s a recipe for permanent cracks where the two dissimilar walls meet. Best method is to hack a strip of the plaster/base coat back on the old wall (assuming it’s plastered!) & position the studding so you can overlap the existing (now bare) wall with the new PB by at least 200mm but the more the better. The new PB should be set so it ends up flush with the original plaster level (use drywall adhesive here). Make a raged edge on the old plaster with a hammer & fill out the gap between the two with Bonding plaster, apply 3 overlapping layers of reinforcing tape over the join & re-skim the whole wall.

 

[craig1]

Cheers for the advice!! I take it the other option is to fix the stud level with the old wall and board over using adhesive on the small wall area..

 

[Chukka63]

you could possibly line the new plasterboard with the old plaster and then skim and reskim the old wall in one operation.

 

[Richard C]

you could possibly line the new plasterboard with the old plaster and then skim and reskim the old wall in one operation.

I thought that’s what I said but not sure ; or do you mean extending the D&D boards over the old wall as well

 

[Chukka63]

dont think so.you mentioned hacking off plaster etc.i was suggesting butting the stud work to the wall.then tape the joint and reskim the existing wall and skim the new wall in one.9similsr idea admittedly)
the other option is what richard suggests of re-D&D the whole of the existing breast.

 

[Richard C]

i was suggesting butting the stud work to the wall.then tape the joint and reskim the existing wall and skim the new wall in one.

You’re missing a trick & the point of my original post Chukka; that’s what the OP was going to do originally but the problem with a butt joint of new & old is that it will almost certainly crack along the line where the 2 meet. Hacking back the original plaster skim & base coat allows you to board over a bit of the original wall which supports the join so much better & means there is far less chance of cracking at the join; I’ve had butt joints crack but never had an overlapping joint fail. Same thing works equally as well with closing off old door openings if you don't want to block them up; always best though.

the other option is what richard suggests of re-D&D the whole of the existing breast.

Agreed; it’s a better solution if not much of original wall is left to cover; less hacking about & a bit more D&D but loosing a ½ inch or so will make no difference at all.