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.
Yes it does make sense to fill it. Insulating foam or insulating glass fibre or Rockwool batts are typical.
However, if it is a dwarf wall - say up to about 6 courses of bricks - then the glass will represent the bulk of the heat loss anyway.
It is worth going for low emissivity glass with the double glazing space gas filled.
Another thing that should be included is to insulate the floor. Styrofoam is used for this, I believe typically of 100mm thickness, and is quite cheap.
Thanks. It made sense to me but every (commercially built) one that I checked seemed to have used something like 1-2cm thick foam. Cheap?
Probably.
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.
Having said this, the windows are gonna be a much bigger heat loss/gain problem.
Rick
Many thanks for those leads.
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
It all adds up. The floor is a large area and added to the dwarf walls a reasonable percentage of the overall area, so worth insulation well. If the conservatory is against the outside wall of the house the conservatory acts as an extra layer of insulation on that wall. As no rain will penetrate this section outside wall, full filling the house wall against the conservatory is a good thing. The problem is getting inside the cavity, so a spray in foam would need to be used.
Umm.. It's a conservatory...
A single glazed conservatory would be cold, whatever. Evene if you also had insulated roof blinds...
All true apart from a)... it's a conservatory......
He has been at the sherry again.
??? You can insert insulating batts or Celotex while the wall is being built.
The existing house wall. Duh!
The question was about the new wall not the existing. Try to keep up.
You must learn to focus.
I am thinking of having cavity wall insulation injected into my house cavity. Are there any negative points in having it done? Are there different types and which is the best? The part of the house in question is about 40 years old, the new extension part is already insulated. Thanks for any comments. Neil
I had cavity wall insulation installed at the same time my new boiler was put in back in April, which was a bit of a mistake, due to the fact he was still sorting out the new flue at the time - so all the new insualtion blew out all over the place.
I think they all pretty much use the same material now-a-days, which is sort of like a feathery, cotton wool kind of thing.
Neil expressed precisely :
We had it done about 7 years ago...
No problems noted and the house does seem to retain its heat for longer.
Mine was done 10 or 15 years ago (previous owners) and doesn't seem that great - it doesn't extend above the ground floor all round the house.
Also when I got the govt sponsored bods along to assess the options of grant assisted loft insulation (none!) they observed that they would not top up any existing cavity wall insulation, not because of unknown provenance (same big UK firm whose name I forget installed it originally as came to do the loft inspection) but because they do not add to existing installations, and he said no one else would.
FWIW
Richard
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