Sheep’s wool insulation is a fantastic product to use for both sound and thermal purposes. 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, biodegrable, and durable.

Advantages of sheeps wool insulation

  • It’s hygroscopic, or water loving. 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 has excellent acoustic properties.
  • Wool is a resilient material and 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.
  • It’s flame resistant.
  • Treated with borate, it is also pest resistant.
  • It’s an air purifier. It naturally binds to SOx, NOx and formaldehyde, keeping indoor air clean.

Oregon Shepherd Sheep’s Wool Insulation, loose fill

 

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

Black Mountain Sheeps Wool Insulation

Black Mountain Sheep’s Wool Insulation, available in batts

Certifications:  All wool insulation products we’ve researched have a Class A fire rating tested under ASTM E84, which is the best fire-rating available. ASTM ratings are American. Unfortunately, the Canadian building code does not recognize wool insulation as it has not been tested in a Canadian lab. To use wool insulation in a Canadian structure you must get a qualified engineer or architect to sign off on it in order to conform to building code.
Embodied Energy: It takes about one tenth the energy to process wool insulation than it does to produce a petroleum-based insulation. Part of the issue is the amount of methane sheep produce. Methane, although less abundant in the atmosphere than CO2, is a more potent greenhouse gas by about 21-25 times as much. In general,
Andrew, from Black Mountain Natural Insulation gave a comprehensive answer regarding the energy calculation for the insulation, which I’ve posted below. It’s important to note that when it comes to calculating energy balances and carbon footprints, European companies 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.

Where to buy wool insulation

At this point the most widely distributed wool insulation in Canada is Havelock wool insulation. You can read about it here.

If you want to read more about the challenges facing the wool insulation industry, this is a good article on a fledgling project at Dalhousie University to find markets for leftover wool such as the insulation market.

In addition to Margaret Magruder at Oregon Shepherd and Andrew from Black Mountain, I’d like to thank to Michael Sinclair at Living Rooms in Kingston, Ontario, and Phil Walsh at Havelock Wool for answering my neverending questions about wool insulation.

Feature photo through Wikimedia: By 4028mdk09 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8031678

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