Loft or Roof insulation?

[halo34]

House has loft conversion but I suspect not much insulation between the roof itself and the plasterboard judging by hold cold that area gets (upstairs rooms have a "slant").

Is there any safe way of gettiing some insulation into the space w/o affecting the air circulation you have to have between the floor and the roof tip?

There is a box space running the length of the house either side before the roof slants so I can get access to where it starts to go up (if that makes sense?)

[Busamav]

Rigid board insulation will be your friend here, search Kingspan or Celotex.

Just ensure you leave a minimumm 50mm free air space over the top of the board , and do not restrict the airflow at the top or bottom of the slope.

[eps]

You'll need about 150 of Celotex in there.. You'll probably struggle with the depth of joists to give the 50mm air gap needed. I'd fill it up to the 50mm gap, probably 170 - 50, so 120.. Then look at trying to attach 30mm of celotex under the rafters. That should give you .16 which is the target U value for insulation at the Roof level.

Celotex do a handy online calculator which can help you..

Ideally we need to know the depth of your rafters.

[robwilk]

Are you intending to remove the plasterboard or try and poke it behind it.
problem with that is there is probably wooden " noogings" between the joists holding them in place during construction.
I have just put rockwool in mine but I have a warm roof constuction so I dont need the airgap.
good luck.