Insulation - difficult loft space

shopbot

Please can I pick the forums brains on the best way to approach the following?

I have a top floor flat. It gets very cold in winter and I want to improve the insulation in the loft above.

Internally each room has a partially sloping ceiling cutting off the 'corner' on the external walls. This results in long eaves in the loft which look similar to this (not mine): https://www.flickr.com/photos/bucklevision/6140362836/

The loft space has about 70 cm of insulation but its very patchy.
It's a cold roof so the eaves can't be stuffed with insulation and need venting space. Currently they have no insulation and the ceilings adjacent to the north wall have suffered from mould.

The rafters are irregularly spaced and have spacing averaging 50cm, the ceiling is very low, (1.25m at it's max) and the way the vertical rafters are arranged it will be very difficult to access the further 2/3 of the loft.

I don't think free insulation will be approved because of the loft layout and accessibility. However I do need to something and would appreciate the forum advice!

I think it will be a very difficult job to get traditional rolls of insulation into the space between the rafters. For the flat part of the roof I was considering using loose fill insulation and pouring it into the spaces between the rafters. Once they are filled I thought it might be easier to get rolled insulation done.

I'm at a loss to know what to do with the eaves especially the far ones. We are possibly going to have the sofits replaced in two years and I was thinking that might be a good opportunity to have Celotex (or similar) fitted into them from the outside. EDIT As it's flat it should allow the ventilation to come through above.

Apologies for the lengthy post - all help gratefully received!

Thanks
SB

zaax

You will need some sort of ventilation in the attic otherwise it will get damp and cause problems.

ThermaWrap
http://www.screwfix.com/p/thermawrap-loft-insulation-0-6-x-7-5m/29949

UKSBD

Have you enough height to put Celotex under the existing ceiling and side rafters?


It would mean having to plaster and decorate but it at least gives you another option.

shopbot

UKSBD wrote: »

Have you enough height to put Celotex under the existing ceiling and side rafters?

It would mean having to plaster and decorate but it at least gives you another option.

That's a very good suggestion - thanks. Unfortunately at the moment I don't have the financial means to get that done. However if I do the loft space it falls under communal areas and the joint maintenance fund for the flats will pay. (I've informally sounded out the Directors).

SB

TheCyclingProgrammer

We have these in our house. They are sometimes called "skeilngs". We had British Gas out to survey our loft for free insulation. The two extensions on our house are quite well insulated (they are about 25 years old) but the main part of our original roof has about 100mm of insulation. The skeilings have some insulation in them but only enough that they aren't blocking the eaves ventilation.

The British Gas guy was very wary of the job and said BG generally won't touch houses with skeilings due to the difficulty in insulating them properly. I did my own research that seemed to back this up. As he explained to me, if you just topped up the insulation in the rest of the loft, you'd create cold spots on the skelings causing moisture to condense on the sloped part of your ceiling and it won't be long before you have black mould growing. He said it wasn't worth the risk unless you can insulate the skeilings to the same degree (without blocking your eaves ventilation) too. When I looked into doing this the two main options were:

a) Raise the roof - costly and expensive (see: http://www.tlxgold.co.uk/skeiling.php)
b) Lower the ceiling

I'd forget option A. Option B depends how much effort you want to do to and how much ceiling height you're willing to sacrifice.

We decided it wasn't worth doing.

shopbot

TheCyclingProgrammer - Thanks so much for your reply. I'd not heard the term Skeilings before despite lots of Googling. Now I've Googled it I'm getting better search results!

Option A won't happen because it's a block of flats and would need a vote.

Option B will need to wait until my Finances are better.

I understand your point about cold spots. I had black mould on the north sloping ceilings until they were painted with an special anti mould paint. However I need to do something as last year in February my Electricity Bill was £4.18 a day (and that's on a low tariff). We don't have Gas in our area. Combined with storage heaters, Winter is a time of either being too cold or too hot with very uneven heating from room to room!

SB