Attic insulation for new build

Deirdra

Hi,

I need some advice re attic insulation. We had thought we were going to go with spray foam & had various quotes but after doing some research here & talking to a few, hopefully impartial people, we have decided this is not the way to go for us.

We are now looking at sheeps wool insulation. This has been recommended to us but we can only find one supplier in Ireland & its working out roughly €50 for a 140mm thick roll. We would need 50-60 rolls. This seems quite expensive in comparison to the regular fibre glass but is working out a good bit cheaper than the spray foam.

Basically myself & my husband have no knowledge in this area & are looking for some genuine advice. Is sheeps wool a good way to go? What other options should we consider?

Thanks


edited to add: I probably should have said the product we're looking at now is thermafleece ecoroll. its thermal conductivity is 0.039 W/mK. Is this good?

BryanF

Sheep wool is the dogs bolzxxx- it's natural, sustainable etc.
Any of the mineral wool products are cheap and cheerful. Cellulose may be another option, we would need to know how good your vapour barrier/ ceiling air-tightness is.

SiegfriedsMum

BryanF wrote: »

Sheep wool is the dogs bolzxxx- it's natural, sustainable etc.
Any of the mineral wool products are cheap and cheerful. Cellulose may be another option, we would need to know how good your vapour barrier/ ceiling air-tightness is.

Wool as an insulator sounds great, but the expensive price is an issue for many people. The purpose is to insulate and I've known many people think wool is a great idea until they find out it's comparatively expensive. Personally I dont buy the "green" wool arguments and would be much more convinced if wool was used as a substitute to petroleum based clothing garments such as fleece's.

olympicweights

I would suggest using cellulose insulation, one of the best out there, just protect you eves so the the roof is still ventilated.

Deirdra

Thanks for the replies. We went to the ideal homes expo today but are none the wiser. obviously everyone thinks their product is the way to go :eek: we're now getting hounded by sales rep for a spray foam installer who is telling us we're making a big mistake if we dont go for the spray foam.

As I mentioned in original post, we really havent a clue! We have one long living space in the attic. do we need to insulate the attic floor ( maybe a wool?), around the walls of the living space & also underneath the felt on the roof? one guy today suggested we use a foil product under the felt

BryanF

Deirdra wrote: »

Thanks for the replies. We went to the ideal homes expo today but are none the wiser. obviously everyone thinks their product is the way to go :eek: we're now getting hounded by sales rep for a spray foam installer who is telling us we're making a big mistake if we dont go for the spray foam.

As I mentioned in original post, we really havent a clue! We have one long living space in the attic. do we need to insulate the attic floor ( maybe a wool?), around the walls of the living space & also underneath the felt on the roof? one guy today suggested we use a foil product under the felt

if a sales rep hounded me, id tell him where to go:D

if you dont have clue, there's a simple answer: pay someone else who does. how many hours have you spent trying to figure this out? cost of attending trade show etc? what about going to the architect that did your house drawings and should have prepared a specification..

why insulate the attic roof? useless your going to use the space? otherwise insulate the ceiling.

forget the turkey wrap, if moneys tight get +400mm of mineral wool: Knauf ,rockwool, isover, etc there are loads of products on the market just pick one!

riclad

see here
<SNIP>
When Swedish builders put 3 x 10cm layers of insulation in an attic floor they always put a layer of building paper between each layer of insulation. This improves the effect of the insulation by 60% because it stabilises the trapped insulating air in the insulation and stops the wind blowing it away.

MOST IMPORTANT,
If the moisture level in your insulation increases by 10% the U-value is reduced by 30%, so naIf the moisture level in your insulation increases by 10% the U-value is reduced by 30%, so natural hydroscopic insulation that can dry itself out like Cellulose, Sheepswool, Hemp etc,. works much better in the long-term by allowing your timbers to breath/sweat and by maintaining the U-value of the insulation.tural hydroscopic insulation that can dry itself out like Cellulose, Sheepswool, Hemp etc,. works much better in the long-term by allowing your timbers to breath/sweat and by maintaining the U-value of the insulation its If the moisture level in your insulation increases by 10% the U-value is reduced by 30%, so natural hydroscopic insulation that can dry itself out like Cellulose, Sheepswool, Hemp etc,. works much better in the long-term by allowing your timbers to breath/sweat and by maintaining the U-value of the insulation. If the moisture level in your insulation increases by 10% the U-value is reduced by 30%, so natural hydroscopic insulation that can dry itself out like Cellulose, Sheepswool, Hemp etc,. works much better in the long-term by allowing your timbers to breath/sweat and by maintaining the U-value of the insulation.

just make sure not to block up any existing wall,roof vent.
dont forget a vapour barrier on the warm side
of the insulation.

i think spray foam insulation is too expensive for most people.
i,ll be insulating my attic soon,
i intend to put in at least 2 inches in each rafter over
ceiling,inside attic.
i,ll probably put on a vapor barrier, leave air gap,
then use insulated plasterboard , under the roof tiles.