Repairing a wall after removal.

29 Oct 2009
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United Kingdom
Hello All.

I am about to cut out part of a T shaped concrete block wall which has pb dot and dabbed on both sides. It will leave an external corner with plaster on block on one wall and plasterboard dot and dab on the other wall. The corner is going to be a right mess once the other wall is out and was wondering what would be the best way to get it back to looking presentable.

So basically how can I finish an external corner where plater on block meets plasterboard.

Thanks in advance for you help.
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I'd temporarily plumb and fix a straight edge down the plasterboard corner of the wall, then use bonding plaster to patch/flush off the exposed end blockwork, in line with original plane of the block wall.
Buut,,,, before i plastered onto the exposed blockwork end, i'd cut/trim back the original plaster by 3 or 4 inches to make sure the original plaster surface plane is "flat". Once the plaster on the block end has set, i'd remove the straight edge from the p/boarded corner, then fix a thin coat bead down the corner, that now meets the bonding plaster, then i'd pva and skim the two walls.
I should have mentioned earlier, but i would also bed a length of 3" jute/hessian scrim onto the "new wall corner", where the plaster meets the plasterboard before i fixed the thin coat beading. It depends on your ability, and how much work you want to put into it.
As i said,, i personally would completely pva and skim the 2 walls, but you could if you wanted, feather away the plaster to nothing on both walls.
Don't forget to damp down/pva the blockwork and existing edges of the old plaster before you coat onto it, to fill out the corner.
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ok i think i get what you mean,

I have never plastered before except I patched a 3ft gap in some plaster board a had to sand it flat after it all set lol.

I dont want to skim the whole wall where the platerboard is as that is the inside of the stair well and the wall goes all the way up to the next level and there is no way I could achieve a pro or even decent DIY finish on that bad boy.

Im going to give it a go with and try to feather it out. maybe with the sander lol once its on there.

Can I just ask a few questions.

would I use the bonding plaster but not come flush to the suface of the existing wall then finish off with finishing plaster?

Should I put the beading in the bonding layer?

Should I use the scrim where it joins the existing plaster and on other wall plasterboard?

And any other questions you think I may need to answer too to avoid a balls up.,, Im guessing i'll only need pva is I intend skimming the whole walls which I dont.

Thanks so far.

and in advance.


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