Maximum Luminaire Weight Supported by Plasterboard Ceiling

[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.NoLinkingToThis/p/gripi...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.

 

[Toneyz]

I have never used them fixings that were on Dragons Den so cannot comment however they would only dissipate the weight over a small area. With a piece of ply/wood through the existing hole, the weight is spread over a larger area. This is the method that I have used before many times and never had a problem.

 

[Rpa07]

How can the noggin idea be rejected when they want a heavy luminaire and you have more experience than them? - beggars belief, some people’s attitudes!

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



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.

 

[telectrix]

ytou can fix with a 1" threaded bolt through the joist but you can't allow for fools ( and horses).

 

[Dave5678]

I've been back and weighed the light. The good news is that it's "only" 6kg, so just into the category of requiring support cables in addition to the flex.

Secondly, I've come across the following test video which has the test force in the appropriate direction. Not only does it show these fittings supporting a large force but that the plasterboard blows where the fitting is rather than cracking out to some other point. I know the structure holding the test device is narrower than the width between joists but I think the point still stands. With some reinforcement behind it to spread the load over a wider area (as suggested by Anthony) I think it is probably going to be quite safe, unless anyone can see a flaw in my thinking?

The Fischer website gives values for the fittings that are derated for safety to about half of those seen in the above test but still above (3x) the weight of the light. With multiple fittings the load is even further below the rating of a fitting.

 

[richy3333]

Can you not just use super long screws to pass through the cavity and screw into the laminate floor above? If the screws poke through the laminate just stick a book over the exposed dangerous point