Insulation Query-walls formed by sloping roof sections

[DM05]

I have a room which seems quite cold, there is insulation in the attic above so not much heat is escaping through the room ceiling however the sloping house roof forms part of the walls in the room and obviously there is heat escaping through there(I would imagine). I looked up in the attic and could see that the (difficult to reach) sloping area doesnt look like it has insulation(just a gap of about 30cm btwn plasterboard and roof). Is there a special sort of insultation that can be used on these 'slopes'?...I would reckon that normal thickness insulation wouldnt be useable here as it would be difficult to slide it down the sloping roof section.
Hope this sort of makes sense...
thanks in advance

 

[stevenrafferty]

I have the same issue in my house and sumitted a post here previously.

I think the main answer was that you shouldn't insulate as there needs to be air movement across this area!

But I think if it was suitable to insulate (I thought of using the rigid polystyrene slabs and sliding them down the space) the saving in heat loss would be quite high

 

[masona]

How about the slab insulation and cut it undersize then slide it in?

Wickes do slab insulation or polystyrene sheets.

 

[stevenrafferty]

Thats what I thought.

But could this cause any problems with damp, etc, by restricting the air flow?

I had thought of using a polystyrene slab which is thinner by 20-30 mm that the actual gap.

Would this allow enough air flow?

 

[masona]

I didn't see your post, I must type faster!

Polystyrene slab are available in 25mm & 50mm thickness, 50mm will be okay on 100mm rafter leaving you with 50mm air-flow gap which is approved from the building regs.

 

[DM05]

Great, so as long as I have about 50mm gap I should be OK? Cheers will give the blocks a try.

Just thought of another similar issue with the room. The sloping walls have an alcove bit (where the window is) that sticks out...the alcove has a flat ceiling, but as far as I can see you can't actually access this area from the attic to put down any insulation. Would that be correct or should that part be accessible?

thanks again

 

[masona]

Would that be correct or should that part be accessible?

Not unless you have a electricial junction box up there that need to be accessible.

You can buy Loose-Fill Polystyrene for awkward area.