insulation between roof and sloping ceiling?

foreign_correspondent

Hello, wonder if anyone can advise me...

I need a new roof at some point in the very near future.

I also intend on adding to my loft insulation ASAP - but, whilst re-roofing, I want to consider all the options - the bit that concerns me is that for about 5 foot of the pitch of the roof, there is no loft space, as there is a sloping ceiling directly under, and parallel to, the roof tiles.

I assume a lot of heat will be lost through this section...

I have spoken to a few roofers, and some have advised putting some sort of insulating board under the tiles on this section - others have just said felt.

What is the best thing to do, and should it add a lot to the cost of the roof?

many thanks in advance!

fc

dave82_2

Hi,

I have the same at the back of my house. I have insulated using superfoil. It is no where near as good as rockwool but it is better than nothing.

It also allows ventalation into the loft as stuffing rockwool down these gaps would block the eves.

The super foil is stapeld onto battons as it needs air underneath to be effective.


D

unluckychappie

A similar construction of tiles, felt, 100mm void, plasterboard on a 45 degree slope. In my case the tiles and most of the felt was sound so insulated by removing the plasterboard. Insulation board is readily available if working from the outside.

I used expanded foam rafter insulation, slots cuts so really easy to cut to width, from Wickes, and then a layer of Thermawrap, leaving a 50 mm void. I understand from my roofers who built a 'warm' roof replacement for our flat roof extension that the air gap is not only necessary for proper circulation but also reguired by building regulations.

This insulation has made a significant difference to air temperature and reducing noise.

foreign_correspondent

thanks folks!

moorhen_2

What we'll almost certainly be using in the same situation: http://www.celotex.co.uk/applications/pitched-roof-insulation/between-under-rafters
with 50mm air gap above the insulation, & above fascia ventilation. (We also have no space below the rafters, and don't want to build up above - so just between for us.) I think your building control office(r) would almost certainly insist on the ventilation to prevent condensation accumulating & eventually rotting the rafters. Beware of them insisting on also adding above-rafter insulation (to bring the total amount of insulation "up to standard") as that'd probably mean altering fascias, bargeboards, etc

foreign_correspondent

another query - there seem to be a lot of roof insulation offers around, but all for the soft wadding stuff you put in the loft - is there any help towards buying or installing this sort of insulation?

kabayiri

foreign_correspondent wrote: »

another query - there seem to be a lot of roof insulation offers around, but all for the soft wadding stuff you put in the loft - is there any help towards buying or installing this sort of insulation?

In the Summer, my local building trade centre delivered 10 rolls of the Earthwool type of insulation, together with gloves; goggles; and mask, for £30. An Npower scheme if I remember correctly.

Worth a phone call?

moorhen_2

foreign_correspondent wrote: »

another query - there seem to be a lot of roof insulation offers around, but all for the soft wadding stuff you put in the loft - is there any help towards buying or installing this sort of insulation?

I wish, but none that I know of. Best I can suggest is work out exactly how much you'll need, search the net for the specific product (e.g. GA4000) & then call round builders merchants asking them if they can beat those prices. Beware they'll probably give ex vat prices. B&Q do a limited range including some small sized boards which might be useful, but will almost certainly cost more than from the merchants. You might also get lucky on ebay.

If you find a good source please let me know, as I need a lot more! (I'm starting my search soon.)

foreign_correspondent

kabayiri wrote: »

In the Summer, my local building trade centre delivered 10 rolls of the Earthwool type of insulation, together with gloves; goggles; and mask, for £30. An Npower scheme if I remember correctly.

Worth a phone call?

it's the solid boards I need, but thanks!

System

moorhen wrote: »

What we'll almost certainly be using in the same situation: http://www.celotex.co.uk/applications/pitched-roof-insulation/between-under-rafters
with 50mm air gap above the insulation, & above fascia ventilation. (We also have no space below the rafters, and don't want to build up above - so just between for us.) I think your building control office(r) would almost certainly insist on the ventilation to prevent condensation accumulating & eventually rotting the rafters. Beware of them insisting on also adding above-rafter insulation (to bring the total amount of insulation "up to standard") as that'd probably mean altering fascias, bargeboards, etc

I would be very surprised if you can get enough insulation just in between the rafters, to meet regs - i would be interested to see the calculations you have done to prove the overall heat loss for building standards

moorhen_2

As I understand it the "regs" are guidelines. If we had to alter our very old roof to completely meet modern standards it would involve unaffordable expense and we would just have to leave the roof as it is - practically uninsulated, slowly leaking and slowly rotting. Our BCO is pragmatic and believes that improving it is better than leaving it as it is.