Heavy Plaster Ceiling Rose, CT1 Adhesive & Sealant?

[TheJay]

I have seen this product recommended for the task. I read in the specification it can take 24+ hours to fully cure. Without using drywall screws, how long would it take before it would not need to be supported? It's going into a Victorian house with 20+ feet high ceilings so spending a long time up a ladder isn't ideal.

 

[Harry Bloomfield]

I have seen this product recommended for the task. I read in the specification it can take 24+ hours to fully cure. Without using drywall screws, how long would it take before it would not need to be supported? It's going into a Victorian house with 20+ feet high ceilings so spending a long time up a ladder isn't ideal.

I would give it the full 24 supported. Screws are best, but if you would rather not....

A pair of steps, with a length of timber on top, supporting the likes of a dustbin lid, with an old cushion on top to support it for the 24. I used screws and that method to give better support, with Thistle as the adhesive. I abraded the plaster of the ceiling, to improve the grip.

 

[TheJay]

Thanks Harry

 

[SFK]

Done several of these.
My method:

Good sized hole in middle of rose for cables.
Masking tape together cables and use masking tape to attach a pencil or drill bit onto cables (makes it much much easier to get cables through hole as my arm not long enough to reach arround rose, and stops adhesive getting on cables).
Pre drill three 4mm screw pilot holes in rose in thicker flatter parts.
Counter sink these holes so screw heads will will well below surface.
Use your adhesive on entire back of ceriling rose (I actually used no-more-nails) missing out very center to minimise mess on cables.
Lift Ceiling rose to ceiling and push and rotate to get adhesive onto both surfaces evenly.
Put in Screws and screw to ceiling (does not need to be over tight).
Wipe off any adhesive that splurts out, and push/smooth adhesive in to any edge gaps.
Leave a few days and remove screws, or better to leave them in and cover with some filler.

SFK

 

[opps]

It might be a good idea to seal the back of the plaster rose with something like SBR first. CT1 doesn't adhere to porous surfaces very well.

BTW CT1 seem to recommend their PGB

Power Grab n Bond - TRIBRID - CT1

The revolutionary development in heavy duty vertical bonding. Based on our CT1 unique sealant and construction adhesive formulation. With Power Grab n Bond there is absolutely no need for any additional fixings as it was initially developed for facade bonding.

www.ct1.com

 

[Wayners]

I've put up around 50.
As above I drilled hole for cables.
I put one screw with small washer through to hold plaster rose to joist, in an off centre position somewhere. Light fitting may cover?
Scratch ceiling back to good plaster.
Seal the ceiling and back of plaster rose. Polymer sealer like tilers sealer works well.
I used fast set filler around the edge and where light will be screwed at centre.
Small pot of tile adhesive in the centre area just blobbed.
Problems you can have.

If you don't seal surfaces the adhesive sets before you push it flat and level.

Too much adhesive you can't push rose tight to ceiling. It's just won't go flush. Push too hard trying to get adhesive out it could snap.

I Just put thin line off adhesive around the edge and centre
Tile adhesive in small 10p size blobs every 100mm
Push and turn back and forth a bit. Get screw in.
Damp sponge around edge.
Wait for a few hours to set.
The holding screw can be removed. Depends on light fixtures.

As for CT1.

I'd use fastset around edge. CT1 in centre blobed

 

[Dereekoo]

Just a thought if the ceiling rose wasn't as big as it is i.e. say 50mm in dia would you worry about it dropping off the ceiling, the force of adhesion holding it in place is directionally proportional to its area. I put up a ceiling rose many years ago and I recall the shop assistant advising putting a couple of screws in to hold it in place whilst it set, I didn't bother and would have needed a bolster to break the adhesion/suction when I pressed it into place Perhaps I was lucky?

 

[Wayners]

I used to prop some ceiling roses until adhesive set using some wood in my early days. Then they started to get bigger and more pattern in them, so a prop could mark the plaster so I switched to a screw. Biggest one I put up was around 3 foot I guess. Never had one fall down but it can make you worry a bit

 

[Harry Bloomfield]

Never had one fall down but it can make you worry a bit

 

[opps]

Just a thought if the ceiling rose wasn't as big as it is i.e. say 50mm in dia would you worry about it dropping off the ceiling, the force of adhesion holding it in place is directionally proportional to its area. I put up a ceiling rose many years ago and I recall the shop assistant advising putting a couple of screws in to hold it in place whilst it set, I didn't bother and would have needed a bolster to break the adhesion/suction when I pressed it into place Perhaps I was lucky?

Last December, I got a call from a customer. Mains pressure was gushing through the lathe and plaster ceiling. I took the antique glass chandelier down, and then noticed that the plaster rose was pulling the ceiling down. Concerned about it either landing on someone or damaging the wooden floor, I had to pull it off. It came off quite easily given that plaster was compromised .

It was about 750-800mm, at a guess it weighed in excess of 7Kg.

If I had to fit one that large and heavy, I would definitely make sure that I could get some screws into a joist.

On the odd occasion that I fit plaster of paris cornicing I use nails to lock it in place and then drive in screws as a safety back up.