Make pitched ceiling flat to avoid heat loss?

[Poppletool]

Howdy. I have a cold north facing office room (2.2m wide by 2.2m long) which has a pitched ceiling thats 3.6m at it's peak.

The ceiling has pine cladding and under that is some pastic sheeting then insulation roll.

Looking at the heat calcs if I made the ceiling flat (say 2.4m) I would need a lot less heating in the room.

If I used an insulated plasterboard with vapour layer would I need ventilation in the void that would created between the old pine ceiling and and the flat roof?

 

Any advice on this would be great thanks

[JohnMo]

Obvious question - why not overboard the existing ceiling with insulated plasterboard, keep the head height and room feeling and reduce the heat loss? Instead of making a new ceiling structure etc... And making a room that will feel small.

[Poppletool]

Thanks for the reply JohnMo.

 

I was thinking of lowering the ceiling because of the heat calcs - seems it requires 50% more watts to heat the room with the current pitched ceiling.

 

Would overboarding alone would work as well?

 

Thanks