John Cartmell wrote:

In article , Rick
wrote:

On Fri, 22 Jul 2005 21:09:32 +0100, John Cartmell
wrote:


I'm looking to add insulation to the cavity in a conservatory wall during
building but I'm not clear what thickness of material to use. I had
assumed that it would be necessary/best to fill the cavity but
investigations suggest that less than 1/3 this thickness seems to be
generally used. Is one option a false economy or the other a waste of
money?

NB We are intending to use the room in all seasons.


From whant I found when I built my house, u have 2 choices


100mm full-fill cavity bats, they must be the "full fill" type.


OR


50mm kingspan, held against inner leaf.


Both have the same U value. The kangspan can not be used as "full fill".


The floor, you can put 100mm kingspan in.


Many thanks for those leads.


Having said this, the windows are gonna be a much bigger heat loss/gain
problem.


Very true! ;-)


Well. yes and no. Per unit area, yes, if left with curtains undrawn.

BUT.

(i) Windows are a small fraction of the total wall area
(ii) heat gain through them even in winter sun is considerable
(iii) if draightproof and tioghtly closed, use of thick interlined and
lined curtains turns them into a perfect insulation sandwich.

I've got single glazed windows but well curtained and sealed, and
believe me, they keep the cold out. Condensation is the most problematic
in the rooms without open fires