DIY question!

[Mixersmate]

Morning all -

I have had a false chimney breast built out of metal studwork, then plaster boarded, skimmed, decorated etc...

I would like to hang a heavy mirror (25kgs) on it, the builder placed 2 metal studs for me to hang off, and left me some small self tapping screws that he used to fix the plaster board to the metal studs, saying they will be able to take the weight, but I am concerned as they won't be fastened all the way in as the mirror has the slotted key style hanging points so I will have to leave the heads sticking out by 5mm or so.

Can someone put my mind at ease and tell me two of these little screws will take 25kgs worth of mirror? or suggest an alternative fixing?

thanks!

 

[Grim Reaper]

How long are the screws, how thick is the plasterboard?
If the metalwork behind the plasterboard is only 1-2mm thick metal studding, then the threads of the screw only need to be through it to the point that the screw is at maximum width, so average 5-8mm of screw into the metalwork, 13mm of plasterboard, 3mm skim coat and 5mm of stickout I'd say the screw needs to be 30mm long at least, any more is not going to hold any better because there's only 1-2mm of metalwork holding it in.
He's not left you plasterboard screws has he? thin shank, coarse thread bugle head? If so, I'd consider changing for regular self tappers, and drill a small pilot hole to get the screw thread started in the metalwork, a 5mm screw and 2mm pilot.

 

[dubber36]

Jeez, what is it with lightweight building products these days? Too late now, but surely timber stud framing with 1/2" ply over the face, then plasterboard over that would have covered all eventualities for a couple of hundred years.

 

[Bargy62]

We used to slide timber inside the studding if something needed fixing to it but that's to late now as the metal its self is pretty thin
do you know what size metal studding he used if so make sure the drywall screw is long enough to go through the front and the back of the studding
As just the front and a heavy weight will make the screw tip down
Failing that the likes of screwfix do heavy-duty plaster board fixings
Good luck with what ever method you choose

 

[jimc91]

You could try these, 113 kg weight limit

 

[Mixersmate]

thanks for the advice all, I'll double check everything tonight and hopefully get it on the wall!

 

[Chippie1]

You could try these, 113 kg weight limit

View attachment 150090

Agreed in hindsight should have had extra supports fitted behind board! I would not fix anything that heavy to metal studs they are very flimsy unless filled with timber used to use it on new builds years ago and on door ways they would fill with a batten to screw timber linings to! Can recommend these fixings I’ve used them a few times in my old house on partition walls they can take a lot of weight

 

[Eclipse Custom Vans]

When I worked on site many years ago, any place with heavier items to be fitted in metal studs had wood battens fitted behind, such a door openings etc. You could use glue/mastic behind the mirror to help. Or can you make a panel which screws to the studs first then fix the mirror to that, a backing board as such but make a feature of it?

 

[Mixersmate]

All sorted now guys thanks, pleased I asked other wise I would of gone ahead and used these little screws the builder gave me, they are the same screws he fitted the plasterboard to the frame with, so not substantial. I did send him the mirror information and had it in the room during him working so he new full well that something was required! but I wasn't full of confidence the full time he was there.

I went with these in the end:

Timco Zip-Fix Cavity Wall Fixings 6mm x 40mm 10 Pack - Screwfix

Order online at Screwfix.com. Heavy duty fixing for use in plasterboard, most hollow concrete block, cavity walls and ceilings. Covers a range of wall thicknesses from 12.5mm to 45mm and supports from 30kg (in plasterboard) up to 60kg (in block). Supplied with 40mm and 60mm screw lengths. FREE...

www.screwfix.com

despite the mirror being quite heavy the keyways were extremely small so I had to grind the head of the screw down and part of the neck to fit.

I inserted the fixing then wound a washer with a 6mm nut to tighten everything up then hung the mirror and luckily its still up!

 

[JOG]

Well done! Good idea with the nut retaining the washer too