Maximum Luminaire Weight Supported by Plasterboard Ceiling

[Dave5678]

Are there are any regulations/guidance on the maximum weight that a luminaire can be if it is only supported by the plasterboard ceiling and not fixed to any joists or noggins?

I have a customer who would like a (heavy, but currently unweighed) light fitting from their old house fitted in the new one, but examination of the existing pendant reveals that it is supported only by a circular dry lining box. The dry lining box has words stamped on it something like the following: "Warning. Ceiling determines maximum load. Max 3kg". Does this 3kg come from some official guidance or is it just something the manufacturer of this particular dry lining box has come up with?

The plasterboard is 15mm thick and the mounting bracket for the wanted light is wider than the dry lining box so the fixings would be into the plasterboard rather than using the dry lining box. The room above has a laminate floor so I have no access from above, only through the 70mm hole that has been cut out for the dry lining box. Potentially, I could feed some strips of ply into the hole to try to spread the load and then put wall anchors or similar through both plasterboard and ply, but at the end of the day it is still just the plasterboard that is taking all of the weight.

Is this job feasible or must the customer be restricted to lightweight fittings until such a time as the ceiling can be reinforced properly?

 

[telectrix]

cut ceiling, fit noggin. restore ceiling , fit luminaire. sssimpleesss.

 

[cliffed]

Reminds me on a job last year,real horrible site agent.
Saw me fitting a normal light fitting to ceiling onto joists,he asked me what size screws I was using,I said 2 inch 8 ‘s.
He asked what’s the weight limit on them,I nearly threw my screwdriver at him.

 

[Midwest]

These are good Heavy Duty Plasterboard Fixings | GeeFix UK - https://www.geefix.com/ but I don’t think you’re asking that exactly?

 

[snowhead]

Use good old Butterfly fixings x 4;

https://www.screwfix.com/p/easyfix-spring-toggles-6-x-80mm-20-pack/1936x

Re the Dryline box, that's the max loading the manufacturer puts on the box fixings, but would stillbe subject to a good fixing in the ceiling.

 

[Midwest]

I hate those things.

 

[Rpa07]

I hate those things.

Mildly pleasurable when you get to mount your rose on them using 3.5s, nice a simple thank you someone else!
I’ll use them on vertical walls as much as I need to - especially for wall lights where there is no room for the connections.

 

[Idpost]

These should do the job! They claim to hold 113kg, but that’s probably on a vertical wall. Even so they should be good enough for the heaviest light fittings. Assuming the plasterboard is in good order and fixed to the joists properly.

https://www.screwfix.com/p/gripit-b...h8SE5-MQwplnz7yZpEBoCAXoQAvD_BwE&gclsrc=aw.ds

 

[Wilko]

Hi - on an unsupported section of horizontal plasterboard I don't think there is a safe loading that's been declared, certainly not my left foot anyway. Another vote for @telectrix noggin

 

[The Ghost]

Feed a piece of batten into the hole and displace the weight on to that batten. Two if you feel doubtful.

 

[Idpost]

These should do the job! They claim to hold 113kg, but that’s probably on a vertical wall. Even so they should be good enough for the heaviest light fittings. Assuming the plasterboard is in good order and fixed to the joists properly.

https://www.screwfix.com/p/gripit-b...h8SE5-MQwplnz7yZpEBoCAXoQAvD_BwE&gclsrc=aw.ds

See Gripit Table - https://www.gripitfixings.co.uk/pages/gripit-table for weight limits. As expected it's substantially less at 20kg for loads in tension.

 

[littlespark]

Where’s that post with the picture of the light fitting being held up with strips and strips of gaffa tape?

Problem solved

 

[Dave5678]

cut ceiling, fit noggin. restore ceiling , fit luminaire. sssimpleesss.

Definitely the best solution, but I think the cut/restore ceiling option was also rejected.

These are good Heavy Duty Plasterboard Fixings | GeeFix UK - https://www.geefix.com/ but I don’t think you’re asking that exactly?

No, I was (am?) looking for guidance on what the plasterboard itself can support, as it is always the plasterboard that fails rather than the fixing. I did think about those fixings but had forgotten what they were called so thanks for the link.

Thanks to everyone who has replied.

 

[The Ghost]

Self Drill Fixings for Plasterboards - https://theduckfoot.com/pages/plasterboard-fixings-self-drill
a possible?

 

[AJshep]

Depends on how heavy the light is ?
What I tend to do if you have a large base ( like you do) is cut a 70mm hole in the ceiling, then grab square piece square ply.

Cut a 70mm hole in the centre of the ply (ply doesnt tend to split) then cut a slot from the hole to the outer edge of the ply. This enables you to put a fairly large piece of wood up the hole (if that makes sense
Also useful for fixing circular fan grills up when the screws are close to the edge of the hole.