Repairing a cracked plaster and lath ceiling

[rossyl]

Hi,

We have a cracked with small holes, plaster and lathe ceiling.

We've been told to over-tack with plasterboard and skim.

The issue is that the old Victorian cornice remains. To overtake with 9mm plasterboard and then plaster would not work as it would create a ceiling that protrudes below the edge of the cornice.

Are there any other solutions that you can recommend?
- a type of PVA plaster?
- Using a wire mesh over the plaster and lath and plastering?
- Thinner plasterboard?

Really would appreciate some advice.

Thanks

 

[Jackrae]

One technique involves fitting the plasterboard to within a couple of inches of the existing cornice. There are many cornice styles that have what appears to be a small pyramid shaped cornice standing a couple of inches away from the main cornice so you could get away with plaster boarding. You'll need to fit up some form of edge first to give a sharp line where the plasterboard ends, fit board, skim as required then fit some form of decorative cornice moulding to give the pyramid effect.

Edit :The attached link gives a general idea of what I'm ranting on about
http://www.oracdecor.com/en/c305c212

 

[rossyl]

It's already quite ornate for not a big room, so i'd prefer not to add another section.

I'm thinking a metal lath like this, pinned to the ceiling and then plastered on.
http://www.diy.com/nav/build/buildi...ork/Expamet-Metal-Lath-2500mm-x-700mm-9273221

Any thoughts?

Thanks
R

 

[Jackrae]

You'll be back out to 9mm or so because that sheet won't lie flat so the plaster will have to be quite thick to ensure none of the mesh shows through, by which time it'll also be so heavy it'll probably either crack or fall down.

Is losing 9 or 10mm off the cornice upper edge going to detract from its effect. Sometimes we worry too much.

 

[rossyl]

The view of everyone is that 9mm plasterboard is too think for whats up there. I would've thought that metal lath would work. Pinned to the joists.

The metal lath is very thin, less than 1mm thick. I would not have thought you'd need to put +8mm of plaster up to cover the metal.

I understand what you are saying that there will be hightpoints that might end up requiring a lot of plaster to make it flat.