Sound advice needed

[russellsmiler]

Hope i can get a bit of advice here??
I are boarding out the ceiling in my extension which as a sloping ceiling in the bedroom, I have insulated between joists and was going to fix a standard insulated plasterboard over the joists, however (i work in construction) i had a roll of super dooper supequilt aluminium insulation which sort of flattens down to 15mm ish, i have stapled this on the joists and plasterboarded straight over it, the boards have deflected out betwwen the joists some 4-5mm giving me a slightly billowed surface ( although not much) firstly i think this will be levelled out when its skimmed (espesially if the plasterer is aware of it) but can anyone see any problems for the future with this, i have used 50mm nails to fix the board as screws just cannot go through this quilt without it spiral wrapping, and have nailed very frequently! the nail heads are under pressure so have trebled the nails.

I realise i maybe should of battened it out! but i am were i am with it.

all sound advice welcome!!
cheers
Russell

 

[PrenticeBoyofDerry]

If you have nailed, over time the nails will start to move and pop out. 4-5mm is quite a lot to even out using a finish coat, the plaster would be best advised to build this area out.