Question on strengthening & screwing through plasterboard

[Wazzedup]

Hi all. Hope this is in the right place.

Ive got an interior wall I want to hang a screen on. The combined weight of screen plus arm mount is about 17KG or so.

The wall itself appears to be 2 pieces of 12mm plasterboard backed to each other, without a stud nearby (it possibly has those metal studs but struggling to find even them). One side (with the screen) has been papered, but I have freedom to access the other side and damage it as that room is still to be decorated. There seems to be no airgap between the boards. I cut a small inspection hole in the "back" wall to investigate this.

Obviously I dont trust the plasterboard to take the weight of this and so I was wondering what option I have to strengthen the wall and prevent the screws just pulling out.

My initial idea is to cut out a ~50*25cm hole from the "back" of the wall, the plasterboard which i can damage, put in a sheet of 1.5mm aluminium, and then put bolts with decent washers and nuts through the plasterboard and the aluminium & refill the hole back in. How stupid is this?

Could 17KG (bear in mind the actual weight is less due to the fact that 17KG directly _down_ wont equal to 17KG pulling away from the wall) feasibly pull the aluminium through or crack the "nice" side of the plasterboard? From some basic googling of how much weight you can hang on a plasterboard anchor (with comparatively little surface area to a 50*25 sheet) some of them are rated up to 10KG, so it shouldnt be an issue of the plasterboard strength?
Should I worry about the bolts being able to pull through the aluminium?

Any other/better ideas on how to strengthen this which dont require taking down the whole wall, or damaging the wallpaper on the "finished" side?

Thanks

 

[23vc]

Fix 3x2/4x2 studs/noggins from behind?
Or, as you say, the load spread between several proper plasterboard cavity fixings like the toggle type fixings, should be ok, especially as it’s double boarded.

 

[Wazzedup]

Hi,

I think this has been misunderstood. the entire wall is composed of the 2 pieces of plasterboard. Id like to avoid having battens/fixings sticking out into the other room, so my proposal was to cut one of the pieces, place the aluminium plate against the other "single" piece, and then fill in the gap in the "other wall". there is no cavity to play with and no space to hide wooden battens.

Thanks in advance for any advice.