Sheeps wool insulation

Gordon Gekko

Hi folks,

I posted this on the DIY/Gardens section, but might get a better response here!

Does anyone have any experience of putting sheep wool insulation in their attic.

It looks like it'll work out about twice as expensive as standard fiberglass rolls for my circa 35 sq. m. attic. I have just about come to terms with the price difference compared to fiberglass, and am willing to pay it because of the significant environmental and health benefits associated with it, and the fact that it continues to insulate even if wet, unlike every other type of insulation.

I note from the website above, and from US, UK and New Zealand websites, that sheep wool attic insulation is claimed to be a more efficient insulating material than other types of attic insulation.

Does anyone know if this is actually the case, or if it is merely marketing bumfph? If it is true, could I get away with less than the minimum recommended for fiberglass rolls, i.e. 200mm? I was thinking maybe 160mm might do it.

I'd welcome any and all experiences/thoughts etc!

Thanks in advance.

Pocari Sweat

Sheep seem to be warm enough in all weathers, and I wouldn't skimp on laying it down, every extra inch will bring a return on investment up to a point. I think ceiling / attic thermal losses are about 20% of overall heat losses, so don't go too daft on it though.

timmer3

i'm looking at this same issue now, and notice this post is a few years old. has anyone since had experience with sheep wool insulation? like the OP i am prepared to pay the extra, i love the thought of my attic being wrapped in one-foot-thick giant wooly fleece.

Dades

I recall an episode of Grand Designs where someone was building a seriously eco-house, but was using glass wool insulation as they would need 4 times the thickness of sheepswool to get the same effect.

Instead he used the glass wool to fill the same area he would have used the sheepswool in, and justified this by saying in the long run the heat saved would make it more eco-friendly.

Beware of trendy solutions, perhaps!

timmer3

thanks for the reply. i know what you mean it is very trendy and eco etc., but i'm also looking at possible health benefits which are probably not well understood currently, in terms of long term effects of building pollution etc., look how long it took for people to take radon seriously, and still so many homes in high radon areas don't have adequate barriers, if at all, or are even aware of it.

i would question where the figures for 4x required thickness came from, just because a bloke on grand designs compared 2 products, he might have been given information by a builder who was on commission with a glass wool supplier... i looked up some figures etc from wikipedia - sheep wool and a table of r-values and this discussion on insulation types. this sheepwool has conductivity of 0.039 W/mK and it compares itself to glass wool at 0.044 W/mK. not sure what this means in R-values but based on the wikipedia articles they both seem to perform at around 3.5-3.8 per inch.

if it performs as well as the other top-rated insulations, and if the cost is bearable to the home-owner, it seems to me like a very compelling argument for sheep wool. mainly for the health benefits (mould resistance and absorption of harmful building gases such as formaldehyde, nitrogen dioxide and sulphur dioxide) and capacity to absorb moisture without causing damp.

i'd be interested to hear other points of view.

Macha

I'd just let you know that there is a guy that sells sheepswool insulation in Rathdrum. He uses Irish wool but it is sent to Germany to be produced. Then there's a company in Wales that uses Welsh wool but it is processed in Wales.

Just if you're interested in the embodied energy aspect.

Also, check out SEI for any grants you might be eligible for.

If you're interested in the health benefits, also look into passive house standards (not necessarily to build to that level and be certified but the principles). Airtight houses are also very good for allergies, etc. So internal and external membranes might be of interest to you.

Also, check out www.greenspec.co.uk for more info, particularly on manufacturers. This is the relevant section:

http://www.greenspec.co.uk/html/products/list681a.html

hick

the episode of grand Designs referred to above was on again recently, the person in question had done all their own research and found the MEPS board (high pressure foam) not fibreglass as mentioned above was the best form of insulation for roof space. Despite the "unenvriomental" manufacturing process of these MEPS boards they pay for that and themselves many times over as unlike fibre glass or sheep's wool it does not need to be replaced due to sagging and wear every 10-15 years (if not sooner) it also insulates in the wet and to refute the R value query above the MEPS boards tend to have R-values that range from 3.8 to 4.4 per 1 inch of thickness (some even go up to 7 or 8!!!) where as Fibre or Wool only get those kind of values from about 8-12 inches pending on the product. And in most cases 2 layers of boards are used!

Just before I'm being accused of being in this business let me assure you I'm not, I'm currently doing a lot of research in trying to insulate my own home but I'm planning to build in the next 24-36 months and wasn't to have as passive a house as possible. And I really looked into sheepswool as a major possibility

You can't ignore some of the synthetic products as the positive attributes in some cases far far out way the negatives and this is one of them

timmer3

Hicks, great, thanks for the clarification.
i found a site that matched your R-value figures. they refer to Polyisocyanurate and Polyurethane Foam Board as having r-values up to 8 etc. currently my attic has 100mm joists and i was planning on adding perpendicular joists @ 200mm to bring it up to the 300mm, but i'm already a bit low in terms of head room so i would definitely consider using something with higher performance to save space. since you've obviously done a lot of your own research can i ask if you know if this would still meet current building regs? i think they specify thickness rather than R-values, which is a bit short sighted if this is so.
btw i found this site that quotes the lifespan of a sheepswool insulation product at 100 years. not sure if one could believe that, but all the sheepwool vendors say it lasts much longer than conventional fibreglass etc.

hick

NP, yeh i'd see that site too. The requirements under the building regulations on insulation are 0.16 watts per M squared they still have in the guides 8-12 inches of Fiberous Insultation but once it meets the technical requirement it should be fine, I'm not worried about current dwelling, but I'd leave it up to the Architect on the new build to ensure met the regs

hick

this was the crowd referred to on the episode of grand designs
http://www.celotex.co.uk/

timmer3

thanks for the info Hick. cheers

joelietz

I'm concerned about the possible health effects of insulating the attic in my old home too. I don't want to do fiberglass insulation but sheep's wool sounds interesting. I have to admit, I hadn't heard of using sheep's wool before for home insulating. Right now I'm considering using a product called Foam-it Green spray foam insulation. It's designed for do-it-yourself types so it appeals to me as I'm very hands on. I'm not too sure how green it is though. I don't want to install anything that I will later regret.

timmer3 wrote: »

thanks for the reply. i know what you mean it is very trendy and eco etc., but i'm also looking at possible health benefits which are probably not well understood currently, in terms of long term effects of building pollution etc., look how long it took for people to take radon seriously, and still so many homes in high radon areas don't have adequate barriers, if at all, or are even aware of it.

timmer3

hi joelietz.
i'm most of the way through my renovation now and i ended up going with rockwool. i think i read too much into the marketing blurb from the sheepswool manufacturers about the health concerns of construction toxins and pollutants getting in to the house from building materials etc., and the sheeps wool will magically absorb them all and keep your family healthy and happy. rockwool is grand, it won't damage your lungs like fibreglass if you do happen to inhale vast quantities of it because the fibres are too big to get trapped in your lungs. but wear a face mask anyway!

i got advice from a senior member of this forum to steer clear of spray foam insulation. the main reason if i remember rightly is because it is (near) impossible to uninstall and leaves an awful mess behind if you do need to upgrade in 10-20 years time when insulation technology has moved on a bit. i was leaning towards it myself but then decided against it. there are very mixed opinions about spray foam, and that in itself was another reason i steered clear, i heard of a house that was devalued by a lot of money when it was up for sale, because a structural engineer saw the spray foam insulation in the attic and said it was a disaster and would have to be removed. apparently not always suitable etc. the claims from the manufacturer are impressive and the fact that it's certified for years in USA etc., but i decided to stick with the generally accepted conventional insulation products. i'm entirely unqualified to credit or discredit any products but that's what i gleaned from my own research.