How strong is plasterboard?

[endecotp]

Dear Experts,

I'm planning to fit a largish desk top in an alcove, resting on timbers fixed to the wall at the back and the two sides. One side is plaster over brick, the other side is plasterboard attached to studwork over a solid stone wall, and the back is a partition wall with just plasterboard over studwork.

The desk, and whatever is put on it, could be quite heavy. I think that I can secure the supporting timbers firmly to the walls with suitable anchors, but do I have to worry that the plasterboard itself would eventually give way? Is there a rule-of-thumb for how much weight I can hang from a wall in this way?

Presumably it would be better to screw through the plasterboard into the studwork - but when I've done this, I've worried that my screws might not have hit the middle of the stud and could be weaker than a plasterboard anchor. Any thoughts?

 

[freddiemercurystwin]

You need to find where the studs are and hit them in the middle or thereabouts. You can use a small drill bit to find them (ie 1mm), drill a series of holes until you establish where the studs are. You should be able to get a good idea just by tapping to star you off. The holes won't ever be seen as you're batten will hide them. Stud finders are none too reliable.

 

[alan333]

Fit some support timber verticals from the floor to the underside?

 

[endecotp]

Yes I could support it from the floor if that were necessary. The question is, at what point does that become necessary? I think people must deal with this when installing things like kitchen cupboards, maybe radiators etc.

 

[tony1851]

Plasterboard is immensely strong when used correctly. In fact, I've just installed an engine hoist in my garage directly off the plasterboard ceiling.

You don't have to fix to the joists, either; I used 4 toggle clips from B&Q (99p) and some nylon chord.

This weekend it's going to be put to the test as I remove the old diesel from my Defender and replace it with a recon. V12.

 

[endecotp]

In that case maybe i'll wait till Monday and you can report back on its strength!

Re "when used correctly" - I really don't know much about these walls, and although they look superficially OK there could easily be some hidden problems...

 

[freddiemercurystwin]

Fit your fixings into the studs. Do a proper job.

 

[loply]

Fixings can pull outwards from plasterboard quite easily.

What they won't do is shear downwards through plasterboard.

In your case, the desk is not attempting to fly horizontally away from the wall, it's attempting to go directly downwards. It's kind of a shearing effect on the fixings.

5 or 6 decent nylon plugs will take a few hundred KG in weight, I bet. Personally, I wouldn't bother with timber, I'd just use a series of small metal L brackets.

Certainly wouldn't bother getting complicated trying to reach the underlying bricks or locating studs, simply no need.

 

[freddiemercurystwin]

Fixings can pull outwards from plasterboard quite easily.

What they won't do is shear downwards through plasterboard.

In your case, the desk is not attempting to fly horizontally away from the wall, it's attempting to go directly downwards. It's kind of a shearing effect on the fixings.

5 or 6 decent nylon plugs will take a few hundred KG in weight, I bet. Personally, I wouldn't bother with timber, I'd just use a series of small metal L brackets.

Certainly wouldn't bother getting complicated trying to reach the underlying bricks or locating studs, simply no need.

I agree any fixings into the PB are unlikely to fail when in shear but its little extra work to locate the studs and probably easier to get a batten level than faff about with a couple of angles.

 

[theoldun]

Plasterboard is immensely strong when used correctly. In fact, I've just installed an engine hoist in my garage directly off the plasterboard ceiling.
You don't have to fix to the joists, either; I used 4 toggle clips from B&Q (99p) and some nylon chord.

Hey Tony,
Do B&Q also supply a suit of armour, or do you wear standard overalls

This weekend it's going to be put to the test as I remove the old diesel from my Defender and replace it with a recon. V12.

Any chance of putting it on U Tube Tony.
Regards oldun

 

[Deluks]

some nylon chord.

From major to minor?

 

[tony1851]

Any chance of putting it on U Tube Tony.
Regards oldun

Sorry, my camera's broke, otherwise I would.

 

[tony1851]

some nylon chord.

From major to minor?

Minor key every time!

 

[ban-all-sheds]

Dear Experts,

I'm planning to fit a largish desk top in an alcove, resting on timbers fixed to the wall at the back and the two sides.

I don't know if this would be acceptable aesthetically (IHNI in what room this alcove is), but here's a design idea:

Once you've found the studs, screw Spur uprights to them and sit the desktop on brackets. I use a length of kitchen worktop for mine, set forward from the uprights by the depth of upstand, which then lays in the gap and gives me a nice removable section for getting plugs and cables through. Have the uprights extend to about 150 cm above the desk and you will find them ideal for shelving.

 

[ban-all-sheds]

Fixings can pull outwards from plasterboard quite easily.

What they won't do is shear downwards through plasterboard.

Ah - the downside of using Spur uprights is that the screws can deflect (unlike when they are through the right sized holes in a few cm of wood)

(Been there, done that with Mk 1 desk )

If you're going to use Spur shelving you have to screw into the wall spurs.

I suspect the same would apply to metal angle brackets.