Sheep’s Wool Insulation in Batts and Loose Fill

March 14th, 2013 by Cathy Rust Leave a reply »

One of the products I’ve been keeping my eye on is an insulation that is made from wool remnants from sheep sheering. I’d first seen it on Building Green where Alex Wilson has written about it, but because I couldn’t find anyone who sold it in Ontario or Quebec I hadn’t mentioned it. But lo and behold, when I was in Kingston at Living Rooms, John Sinclair told me they were now supplying not just one brand of wool insulation, but two! Sheep’s wool insulation fits in with my waste theme this year. It’s a product made from material that is otherwise considered to be waste — remnants that aren’t high enough quality for use in sweaters, carpets or blankets. It is renewable, recyclable, durable and biodegradable. Some of the advantages of wool insulation are:

  • It is a hygroscopic, or water loving, material. The insulation can absorb up to 40% its weight in water and still not feel wet to the touch and eliminating condensation in interior spaces filled with the insulation. This action in turn, prevents mould growth and/or rot.
  • Wool is an excellent acoustic insulation.
  • Memory. Wool maintains its shape and therefore its R value over time.  Because of the natural kink in the fibre, when fibres are side by side tiny air pockets are created which prevent heat from travelling across the insulation.
  • Flame resistant.
  • Treated with borate, it is also pest resistant.

The two brands that Living Rooms carries are:

1. Oregon Shepherd Natural Wool Insulation:This product is excellent for attics and underfloor insulation, wherever loose fill insulation is required. It has an R value of around 3.6/inch. Installation: Although it can be installed by hand, using a blower will allow for maximum effectiveness of the insulation, particularly since it arrives tightly packed in plastic bags. John mentioned that they prefer the FibreForce blower by Intec for the best application.

Oregon Shepherd Sheep’s Wool Insulation, loose fill

 

Oregon Shepherd Loose Fill Insulation, Wall Cavity Installation (netting applied across studs)

Cost: $4.45/lb, although discount pricing may be available for volume orders. It’s best to call to confirm prices. (Prices are at time of writing, March, 2013.)

Certifications: The loose-fill insulation has the following certifications:

ASTM C 518 for R-value
ASTM E 84-09 (also covers UL 723, UBC 8-1, and NFPA 255), giving it a Class A Fire Rating
These are all American ratings. This material does not have Canadian standards testing ratings. As such, it is not recognized by the Canadian Building Code, despite the fact that the testing is conducted by the same labs as in the USA. In order to get around this, the material must be officially approved by either an architect or an engineer.
(Above photos courtesy of Oregon Shepherd.)
Black Mountain Natural Insulation: Wool batts are available in two thicknesses: 3.5 inches and 5.5 inches widths made for 2×4 and 2×6 construction. R-value – 3.5-4/inch.
Black Mountain Sheeps Wool Insulation

Black Mountain Sheep’s Wool Insulation, available in batts

Contents: 92% sheep’s wool + 4% polyester binder made from recycled polyester (for maintaining shape — polyester made from recycled material) + 4% borax salt. Can be recycled, incinerated for additional energy, or composted to biodegrade.

Cost: $1.88/sqft for the 3.5″ thick batts and $2.55/sqft for the 5.25″ thick batts. Again, best to call for a quote. (Note: current pricing as of March, 2013.)

Certifications: ASTM E-84 + UL 723 (Class A Fire Rating), ASTM C1388 (Fungi Resistance), ASTM C518 (R-Value). All these ratings are American. Coming from the UK, these batts also have the appropriate EU standards testing ratings. These batts do not have Canadian standards testing ratings. As such, they are not recognized by the Canadian Building Code, despite the fact that the testing is conducted by the same labs as in the USA, and the EU standards are actually higher than the Canadian. In order to get around this, the material must be officially approved by either an architect or an engineer.
Methane Production: Both companies indicate that it takes about one tenth the energy to process their insulation than it does to produce a petroleum-based insulation. I was wondering if that amount took into account the methane produced during the growth phase of the wool or during the lifespan of the sheep. Methane, although less abundant in the atmosphere than CO2, is a more potent greenhouse gas. In addition to produced from decomposing food and organic waste, it is also produced by animals, cows and sheep in particular. I contacted Margaret Magruder from Oregon Shepherd  and Andrew Ryan from Black Mountain to ask them about methane production.
Margaret wrote to me that the energy production figure (1/10) refers strictly to the amount of energy used in production of the insulation in the factory versus petroleum-based insulations.
Andrew had a more detailed answer regarding the energy calculation, which I’ve posted below. It’s important to note that when it comes to calculating energy balances and carbon footprints, European countries are leaps and bounds ahead of most North American companies. Consumers are also more vastly aware of the consequences of their buying decisions, so they ask these types of questions regularly. Basically, what all this means is that my question about methane production has already been asked many times to the Black Mountain Insulation staff. Here is Andrew’s answer:

We are often asked about the methane from sheep, the answer lies in why sheep are farmed?  They are farmed for the livestock industry and not the wool, the economies of wool don’t even cover the cost of shearing the sheep.  Hence in an LCA [lifecycle analysis] the economic allocation is such that wool is a by production not THE product.

We have worked with a number of persons on LCAs which are not published publically at this point in time, however the foot print for wool is very low indeed. The shipping carbon cost to Canada or the USA is also low since the road miles from us to the docks are low and the carbon foot print of a container ship is also low. Sheep wool in fact locks up carbon dioxide in the growth phase and hence starts carbon negative, which compared to the man made alternatives is a distinct advantage.

 

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5 comments

  1. Cathy Rust says:

    Hi Ken,
    I would suggest you contact Michael and John Sinclair at Living Rooms. They have had experience with getting the sheep’s wool approved for use in buildings. It is fire retardant and hygroscopic while still maintaining its R value. email: info@livingrooms.ws
    Best,
    Cathy

  2. ken says:

    What are the details about getting the house insured with sheep’s wool insulation in Canada? What does the engineer or architect have to do?

  3. Cathy Rust says:

    Hello Harri,
    I would try Oregon Sheperd. http://www.oregonshepherd.com/index.php
    You might want to see if they have a BC distributor.
    Good luck!
    Cathy

  4. Harri says:

    We want to use sheep wool insulation for our project, where in Vancouver, BC can we buy this?

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