Scaffold board shelves - securing to plasterboarded walls with cavity

[voteforpedro]

I am going to fit some scaffold boards as shelves in our kitchen (up to 80cm long). They will be fitted to the wall with cast iron supports with three screws. They will be holding plates, bowls etc... So basically, the brackets will be holding a fair bit of weight.

Now the issue is the wall in question is a brick party wall that's been plasterboarded. The plasterboard is bonded so there's a small cavity between the boards and the brick, maybe 1-2cm. Obviously then I'm not going to be able to screw the brackets down to the wall. If I screw it down to the plasterboard, I'm worried there will not be enough support plus risk of damaging plasterboard with over tightening.

What are my options? My only thought is to cut out a cavity the size of the bracket and screw down some timber first.

 

[ladylola]

Screw a piece of 3/4 ply to the wall first fixing through where the dabs are , filling the screw holes and decorate to match the surrounding walls . Then simply fix the brackets to the ply.

 

[freddiemercurystwin]

Screw a piece of 3/4 ply to the wall first fixing through where the dabs are , filling the screw holes and decorate to match the surrounding walls . Then simply fix the brackets to the ply.

Hmm classy!

Alternatively use something like these: http://www.amazon.co.uk/gp/aw/d/B00...-spell&pi=AC_SX110_SY165&keywords=dvyline+pro

 

[foxhole]

You should be able to secure to plasterboard wall in conventional manner, there should be enough adhesive behind the board to prevent compression when securing.If any holes find cavity behind a short piece of pipe [copper, plastic] will give extra support and take the load back to the brickwork.[or use Freddy suggestion].