Insulating a floor above an unheated garage

[BrokeBeginner]

Hi All

West Midlands based and looking for someone to tell me if I’m going down the right path.

Just finished putting up 8x2 joists for a new master bedroom above my garage and looking to install insulation. Am I on the right path with the below and should I be worried about significant heat loss through the joists?

Top down I’m thinking;
22mm chipboard
VCL
100mm PIR
75mm Rock Wool
Additional 2x2 screwed parallel to the under side of the joists to create service void for garage downlights
15mm fire rated plasterboard
Skimmed
Fire sealed round edges

 

[DAZB]

As far as i know the Regs for a habitable room over a garage is double skin plasterboards with staggered joints and then skimmed and any pipe or cable apertures through the ceiling need fire collars and possibly acoustic sealing too.

 

[Murdochcat]

Shouldn’t you be discussing this with your BCO ?