whats the strongest fixing for plasterboard/ply

[Gary111]

Ive got a heavy water heater (110 kg) fixed by 2 bolts.

Ive screwed 18mm ply onto plasterboard, put coach bolts through , but the last part isnt threaded and its loose to turn so Im not sure if its the best.

Im wondering if theres anything stronger I could use ?
not got clearance to drill a big hole for a toggle though, as the plumbing is all done !

 

[sircerebus666]

You mean you put coach bolts through ply and screwed them direct into plasterboard?

Never gonna hold......

You need to fix the ply to the studs then fix the brackets to the ply if the coach screws are spinning then you could use washers to bring the screw further out so it bites or fix another piece of ply over the top

I find it easier to fit a noggin between studs so you can use the full length of the screw to give a good solid fixing

 

[Gary111]

Thanks, yes Ive screwed the ply on first.

 

[conny]

Is the plasterboard a cavity wall?
If so, simply screwing the ply to the plasterboard is not going to be strong enough to hold the boiler in place. You will need toggle fixings.
If the plasterboard is against brickwork then I suggest to drill, plug and screw into the solid brick behind.

 

[foxhole]

I would remove the plasterboard [template the position and cut 20mm smaller section out] and replace with ply, stronger and boiler should hide the ply.