Fixing a multi-piece ceiling rose

[gmwill]

Context: I recently installed a multi-piece fibrous plaster ceiling rose (i.e. not a complete disk but several independent pieces/leaves radiating outward), around a light fitting. The ceiling is lath and plaster, c. 1910. In the position where each piece would go, I scored the ceiling with a stanley knife to expose some plaster under the paint, and attached the pieces with plaster adhesive given to me by the firm that cast the rose (herculite fibrefix I think). I also put a drywall screw through each of the larger pieces for extra security.

Problem: I installed one of the main pieces/leaves skewed and only noticed afterwards. I reckon most people wouldn't notice but it bugs me every time I look at it, so I want to know if I can fix it easily without damaging the ceiling or the other parts of the rose / light fitting. I have a spare plaster leaf to replace the one in question. My plan is to remove the existing plaster leaf by taking out the screw and cutting carefully through the plaster adhesive between the piece and ceiling with a fine pad saw / keyhole saw or similar (rather than start hacking at it with chisels etc, which would damage other bits and take down some of the plaster on the ceiling with the piece I guess). Then I'll try to sand any remaining adhesive off the ceiling area, score it again, and put the new rose piece up - hopefully straight this time!

Does this sound like a workable plan? Would it be easy to saw through plaster adhesive? Would new plaster adhesive stick on a patch of ceiling where old adhesive had been? Any advice or new suggestions welcome.

 

[Wayners]

What about cutting with a multi tool

 

[gmwill]

I don't have a multi-tool and in any case it is quite a complex shape to get around without damaging the other bits of plaster next to it so I'm more comfortable with a small hand tool. Thanks nonetheless

 

[jj4091]

This sort of thing any use https://www.amazon.co.uk/Xnourney-Woodworking-Flexible-Double-Handle/dp/B0BSKZV6TV

 

[Wayners]

Loads of multi tools second hand for around £10 on eBay or gumtree ect.
Just find one local pickup

 

[gmwill]

Thanks for tool suggestions. Do you think new plaster adhesive will fix okay to a patch of ceiling that is a mix of old sanded-down adhesive and plaster where adhesive has been? I ask because the original adhesive bonded through suction on contact with the exposed plaster. This to me (a total layman) suggests that surfaces other than fresh plaster might offer different degrees of adhesion even if they are well keyed.

 

[Wayners]

Id seal.
Yes a bit of suction is good as it means adhesive sets vs having to wait for the setting time.
I'd use some PVA 5-1 ( wood glue) if you have some. All surfaces.

When fitting period cornice ect plaster of paris is often used. Get online or hobby shop

 

[gmwill]

Many thanks. I'm still a bit unsure why I would want the PVA to seal the bit of ceiling; would this not reduce suction and/or adhesion? My aim is to achieve the same amount of high suction and adhesion with the plaster adhesive as with the original unprimed plaster. I'm only worried that suction/adhesion would be diminished if the ceiling plaster has already absorbed adhesive in that area. The adhesive I'm working with is gypsum-based herculite fibrefix, so not Plaster of Paris I think but a plaster-like substance.

 

[Wayners]

Go with your plan.

I've put loads off plaster cornice and ceiling roses over the years so maybe I'm old school. I've not used herculite fibrefix. I always sealed surfaces and used other products to stick.

 

[gmwill]

No worries. I'll have a mechanical fixing holding it up so I suppose it won't be the end of the world if the adhesive doesn't take and I have to rethink. Thanks for the help.