New Build Question - Insulation in Eaves

Dummy

Hello there.

I am doing up a snag list for my new build. One of the things I noticed was that when I open the small doors that go into the roof space upstairs, there is a very strong cold breeze coming into the roof space.

From what I know you have to allow the circulation of air in this space, but should it be a very strong breeze? I also noticed that there was an absence of roof insulation in this area too.

Is this normal or is it an item I should include on my list?


Thank You,

D

10-10-20

Yes and no.
There should be ventilation but in my mind, not a gust. I have the same issue.
I have Kingspan boards placed between the rafters and the space behind the boards is supposed to be ventilated from the soffits, but in my case there is no seal between the kingspan and the top of the wall, leading to all sorts of wind issues.
If you have a look at page 12 of the following document you can see what I'm referring to:
http://www.insulation.kingspan.com/uk/pdf/tp10.pdf
I'm missing two elements, the seal between the floor and ceiling, and the 'insulation material tightly packed to block cold bridge'. Hence, I get a gust where I shouldn’t. It takes a lot of work to rectify this issue.

Snag it!

garyh3

Hi 10-10-20

Good diagrams. My house was built in 2004 and have the same issues. Is there any way you can put the flexible material as My house does not even have the Cavity closer.

Garyh3

10-10-20

Garyh3 - the prefered method would be to complain to the builder and have him do it - maybe the homebond can help here? Apparently it's against building standards. You would need to get the backing of a surveyort though.

Otherwise, you are left retrofitting it yourself. I haven't even found a suitable material to use in this space as you can't/shouldn't compress rock-wool to act as a draft barrier and expanding foam is too hard to control. What I have been doing at instances where I've required is simply laying rock-wool on the ceiling up to the ridge of the external wall, but this induces air flow in the rock-wool, minimising its effectiveness.

garyh3

Hi 10-10-20

What I have done is just lay a layer of insulation accross the beams at the eves, just left a small gap for air movement but it still does not go to the cavity so there is a lot of air movement in the cavity.

Garyh3

KILRB

Hi there.
I have a problem in a bedroom in my house which has a bay window. The insulation in the house runs out the eaves but it doesn't cover the bay window and there is a lot of heat loss in this room. Should I insulate over the window too?
Thanks a lot.

Mellor

KILRB wrote:

Hi there.
I have a problem in a bedroom in my house which has a bay window. The insulation in the house runs out the eaves but it doesn't cover the bay window and there is a lot of heat loss in this room. Should I insulate over the window too?
Thanks a lot.

yes, you should.
insulate right to the eaves and over into the soffit, not ful fill, make sure you leave at least 50 mm above the insulation.

garyh3

A good thick pair of curtains also saves a lot of heat. We just put the patio curtains up and the difference is def noticeable. Well worth the money...

garyh3