Ceiling repair - your method?

[FredFlintstone]

Afternoon folks,

Question for all you plasterer types.

Where a ceiling has been partially damaged, say by water ingress, and an area of the ceiling needs repairing, how do you go about it?

What I actually mean is how do you remove the damaged area prior to re-boarding and re-skimming? What do you use to cut the boards out? Do you scrim the new board to the existing ceiling and then try and blend the skimming into the new ceiling as best you can or do you try and remove some of the surrounding skim (say and inch all round the edge of the repair) before taping and the skimming to make it blend better?

The reason I ask is that, being a DIYer I've not got any specialist tools for the job. I've therefore just been cutting out the damaged area up to the nearest joist beyond and then using a stanley knife to cut away the board to half way across the joist. However, this is time consuming and painful on the arms and I can't help but think it would be much easier to use an angle grinder or something to provide the cut. It also means the cut would be much neater.

The other issue is blending in. I've found that when replacing a part of a ceiling, unless you remove an inch or so of skim from the ceiling around the hole that you've created, it's nigh on impossible to get a satisfactory join because the existing ceiling is obviously thicker than the new piece of board that you're inserting and therefore you've got a step which needs taping and then blending although blending is impossible without skimming a huge area around the patch (or the whole ceiling for the best result).

Just wondering how you do it and what you use.

Cheers

Fred[/i]

 

[noseall]

it would depend on the size of the ceiling and the customers preference.

 

[Richard C]

Just repaired the ceiling in my bathroom; previous damage was a large bulge apparently caused by an old leak around the stack vent. I cut the ceiling back until I got to sound board (all black & rotten), then cut the boards back to the centre of the nearest joist using a sharp bolster chisel to pierce the plaster & then using a Stanley knife to cut through the board; I ended up with a hole around 450mm x 700mm.

To make an effective & invisible repair, you need to be a bit more brutal than your experience & post suggests; & you will need at least a half decent trowel! After cutting back to sound board, cut a new piece of board to shape so it has around a 2/3mm gap all around the edge; it doesn’t have to be a perfect fit & you certainly don’t want it to be a tight fit! Chisel off some of the existing plaster around the edge of the hole (but not the board underneath). What you actually want is a raged & not a sharp edge as this helps the new plaster bond with the old. Screw the new piece of board into place, PVA the whole area (including the gap) & apply a generous skim of plaster to new board only but leave it about 1mm below the original; make sure you force plaster into the gap all around the edge & let it go off & fully dry. When dry, apply glass fibre reinforcing tape all around the edge of the join, PVA the new board & an area about 450mm all around the hole & apply a finishing skim of plaster over the whole area. You will have to blend the new skim coat into the surrounding area, probably around another 300mm or so if you want to loose ‘the join’. Once set & depending on your skill with a trowel, you may have to give the edges a light sand to blend it in perfectly’ Paint over & if you’ve done it right, no one will ever spot it unless you tell them.

Forgot to add; put some new screws into the old ceiling every 200mm along the joist line to make sure the original ceiling is securely fixed around the repair.

 

[FredFlintstone]

Cheers Richard.

So you skim the board before taping the join - interesting, I'll give that a go.

So I'm right to remove a bit of the old skim around the edges then? I think one mistake I've been making is perhaps trying to get the new board to fit perfectly. Not tightly, but I've been trying to get a decent, uniform gap all the way round the patch which I guess isn't entirely necessary.

I've got a decent trowel - I nice Marshalltown pre-worn finishing trowel. It was the first thing I bought myself after my first attempt at plastering and boy, what a difference it makes to the finish - a lot easier to get a reasonable finish using that than the rubbish cheap trowel I originally bought which I now use to apply bonding.

Thanks again.

Fred

 

[robert99]

I have used a lathe and plaster type repair technique. Screw battens to the joists to take the lathes (with gaps) which span the hole. There is no measuring of any infill board and you can adjust the level of the lathe underside to suit.

Used PVA around lathes and cut edges and plastered in two stages until just below finished level. Used a thin skim of plaster and polyfilla mix to finish and feather in with existing ceiling.

Then sanded in with a wooden block plus medium paper. No scrim and the repair is invisible, flexible and well bonded so as not to crack.

 

[Richard C]

Cheers Richard.
So I'm right to remove a bit of the old skim around the edges then? I think one mistake I've been making is perhaps trying to get the new board to fit perfectly. Not tightly, but I've been trying to get a decent, uniform gap all the way round the patch which I guess isn't entirely necessary.

If you’re trying to ‘patch in’ & get it to stay there without cracking, you need a good key for the new plaster. I chip away & create a rough edge then skim the patch board up to & into this edge & into the gap (but not over the original board at this stage) before applying reinforcing tape & finishing off. This way the repair doesn’t just rely on a thin skim of plaster over the tape & plaster forced into the gap & surrounding chips is bonding the edges together as well; & the rougher they are the better. No guarantees it won’t crack again of course but I’ve had a lot of success using this method. As I said in my last post, always add some additional screws to the original board around the repair area to make sure it’s not going to move.