Weight which can be supported by plaster board?

[ericmark]

I watch eFIXx quite often and 559.6.1.5 of BS7671:2008 says "In places where the fixing means is intended to support a pendant luminaire. The fixing means shall be capable of carrying a mass of not less than 5 kg." I can't see how plaster board can take a 5 kg load.

 

[RandomGrinch]

can't see how plaster board can take a 5 kg load.

You may want to qualify that statement.
A 25kg bag of plaster skim will cover 10m2 @ 2mm thickness.
That's over 8kg of dry mass of plaster per standard sized board at least!

 

[SUNRAY]

I have seen hundreds (if not thousands) of those or similar arrangements with a small wooden batten and generally never been a problem with the fixing.
The 2 issues I do see:
Supports spaced at 2 ft and the fixing being made near a join across that 2ft, the board starts sagging and the join cracks.
Simply not enough fixings (or missing the joist) holding up a PB sheet or the nail gun being too strong and pushing a long way through the board which eventually collaspes under its own weight, plus the plaster and a couple of fixtures. Especially with the engineered (flexible) joists and lots of activity upstairs.

 

[ericmark]

To be frank, not seen many chandeliers which weigh 5 Kg, and I would question if the flex can take that weight. But we don't often know what supports the lights, with my own lights, I know the ceiling rose has reasonably long screws which fixes it to the beam, but if someone else was to unplug it, and plug in a replacement, they would simply assume the person before him had followed the regulations, and 5 Kg falling on one, is something one would not forget in a hurry.

 

[JohnW2]

..... The fixing means shall be capable of carrying a mass of not less than 5 kg." I can't see how plaster board can take a 5 kg load.

I think it's much more a question of the nature of the fixings, particularly the extent to which they 'spread out' the load they are supporting (and how far they are from the supports of the plasterboard), than to the question of 'what weight plasterboard can support.

If one uses fixings which have lugs/arms/whatever which 'spread out' above the board, I think that plasterboard can probably support a good bit more weight than you seem to think.

 

[Notch7]

View attachment 371208I watch eFIXx quite often and 559.6.1.5 of BS7671:2008 says "In places where the fixing means is intended to support a pendant luminaire. The fixing means shall be capable of carrying a mass of not less than 5 kg." I can't see how plaster board can take a 5 kg load.

Don’t use them to fix your pole dancing pole up

 

[JohnW2]

Don’t use them to fix your pole dancing pole up

They are surely supported by the floor, aren't they? Maybe "I haven't lived", but I don't think I've ever seen one which was just 'dangling' from the ceiling'

 

[JohnD]

It is good practice to fix the support to the nearest joist, not the plaster.

Chandeliers usually come with a hook and chain that can be separate from the electrical rose

 

[SUNRAY]

Many years ago I was installing kit in night clubs, one of my young bosses had some brackets manufactured to take some moving head lights, I'm guessing around 10 Kg, the bracket consisted of a steel plate, probably 3mm thick and 300mm square with about 4 or 5 holes each side so total of 12 or 16 and a 10mm bolt welded to the middle. He then used one of these for every hole

, hung the first light and demonstrated how secure it was by doing pull-ups on it. On the 3rd evening of use 2 of them fell, one had pulled down probably half a sheet of PB, the cables in MT2 between them pulled the other down, complete with the square of PB between the fixings. I assume it was the weight of the glass mirror, colour wheels and stepper motors jerking around that pulled the inadequately fixed board down.

 

[FrodoOne]

View attachment 371208I watch eFIXx quite often and 559.6.1.5 of BS7671:2008 says "In places where the fixing means is intended to support a pendant luminaire. The fixing means shall be capable of carrying a mass of not less than 5 kg." I can't see how plaster board can take a 5 kg load.

While one might install a "Batten Holder" on plaster board, I would not regard that as "good practice".
At the very least, a batten should be installed between the adjacent ceiling joists, to support the fitting.

This is one case where our North American "cousins" really do it better.
They have "Ceiling Light Fixture Boxes", which can be inserted through a relatively small hole in the ceiling Plaster Board and then expanded to engage the arms to bite into adjacent joists.

Many of these are also rated to support the weight of Ceiling Fans.

(Look up "Old Work Ceiling Box" on any appropriate North American site.)

 

[ebee]

Personally I have always done one of two things with even the humble pendant.
1/ The rose entry for cables is right by the side of the joist which allows at least two fixing holes to get a good purchase into the meat of the joist (never near the edge of the joist).
2/ If such a position would be bad for aesthetics of the pendant position to the room to the room then a sizeable batten (say 2 x 3) is secured between two joists and the pendant rose is attached to that.

I would never have complete faith in pendants attached to plasterboard only (smoke detectors etc I might fix in position using "Redi Driva" or toggle bolts etc.
Chandeliers or ceiling fans would follow the same batten or joist idea in a similar and usually stronger version of that.

Having said that I have seen it to be not uncommon to to fasten to plasterboards with simple red plugs and screws and even know someone whos habitually screws into the old lathes on a non plasterboard ceiling (ugh).
I once discovered a plastic pendant set held in place on the ceiling purely with double sided tape on the ceiling paper and the lampholder had a glass shade fitted - crikey!
I cringed.

 

[robinbanks]

They are surely supported by the floor, aren't they?

Floor supported, with a bearing both ends so they rotate

 

[ebee]

They are surely supported by the floor, aren't they? Maybe "I haven't lived", but I don't think I've ever seen one which was just 'dangling' from the ceiling'

Yes the floor actually supports them but a good fixing a the ceiling end is also required to counter any leverage and "Centrifugal Force" at the ceiling end - Centrifugal Force is a false force, it does not exist, however the equations for it still hold good in practical terms!

 

[SUNRAY]

Floor supported, with a bearing both ends so they rotate

I assume you are still referring to pole dancing.

ROTATE????? No *****ing way

 

[SUNRAY]

Yes the floor actually supports them but a good fixing a the ceiling end is also required to counter any leverage and "Centrifugal Force" at the ceiling end - Centrifugal Force is a false force, it does not exist, however the equations for it still hold good in practical terms!

It doesn't really matter which way but they need to be firm both ends. At least one needs to be a substantial solid fixing.

I'm not refferring to the toy versions for home use that were designed to jack the ceiling up or punch holes in the plasterboard and create work at A&E.