mini attic

[feverfew]

Hi,
New build bungalow with attic trusses.
I'm installing 100mm celotex between the rafters and 50mm celotex sheet on the underside.
Shall I carry this on over the small ceiling area or just plasterboard it and lay down fibreglass quilt on top.
I assume 150mm celotex would have better insulating properties than quilt although more time consuming to install.
What thickness quilt would be required and would it be a problem in the small triangle area maintaining an air gap at either side?

 

[mointainwalker]

i've tried to follow your description but am not sure I am totally with it, HOWEVER.....

it is absolutely pointless and a major waste of time , money and effort to insulate both the rafters and the ceiling.

Save all of these by just insulating the ceiling with 150 -200 mm of glass-fibre but before you lay this, put in place a vapour-barrier ( i.e. continuous plastic-sheet ) to prevent warm, moist air from below condensing in the insulation.



New Thought:

If this is a new-build bungalow, where is the legally required insulation or is it self-build ?

 

[feverfew]

Sorry about the confusion...
Its a self build bungalow and I'm trying to do most of the work myself.
The attic area will be part of the living space, and as such I'm insulating the roof according to Bldg Regs. ie 50mm air gap under the felt then 100mm celotex inbetween rafters and 50mm celotex across underneath, vapour barrier, batten then plasterboard. It was the mini-attic area I was referring to above the attic ceiling which amounts to a small triangle about 3ft each side. Hope this explains things a bit better...