mike. buckley wrote:
In message om, Dave
Liquorice writes
On 20 Oct 2006 03:45:09 -0700, wrote:
I have already added 170mm on top of the boards.
So the current situation in terms of layers is (from top to bottom):
170mm
Boards
100mm
270mm of insulation plus the thermal resistance of the boards. No more
insulation is required.
How ever is there a gap between the top of the lower 100mm and the bottom
of the boards? That isn't a good idea as it'll allow air flow and thus
removal of heat. Rather than add another layer of insulation make sure
there is no gap.
This is all very well, however I only have room for 100mm of insulation
in the gap between the loft boards and the ceiling. I can't put
insulation on the top of the boards as it's used for storage. So I'm a
bit stuffed as far as the 270mm recommendation goes. I suppose I could
get the inside of the roof sprayed with insulation material, but that
would take too long to pay back.
wont work on a vented roof anyway.
several options
1/. use 100mm of kingspan etc under boards. Best although the joists
will bridge it.
2/. remove borads and lay some 170mm joists across existing, fill with
more rockwool amd reboard..
3/. Lay polystyrene floor slabs (or celotex) over the boards and put
storage on top of that.