Installing sheep wool insulation batts

Three years ago we bought some sheep wool insulation from Oregon Shepherd. The product was actually made in New Zealand, and a couple local farmers had imported a shipping container full of it and stored it in their barn. At the time we were wildly optimistic that we would soon be insulating, so we bought a bale to give it a try. Each 5 foot cube bale contained two vacuum sealed bags full of wool batts. Each batt was 4 foot long, and designed for stapled installation into 2×6 framed construction on 16 inch centers. The particular product we bought is no longer available locally, although Oregon Shepherd is now selling blown-in insulation made from U.S. sourced wool.

As an insulation product, wool has significant advantages. It is about R3.3 per inch, putting it in the same class as fiberglass, but without the associated itchiness, toxic binders, or hazardous dust. It is naturally fire resistant, insect resistant, sound dampening, and moisture buffering. Finally, wool is a renewable resource with far lower embodied energy costs than fiberglass, foam, or rock wool. The only real disadvantage is price–even the scraps used in insulation are labor-intensive to produce.

From an installer’s perspective, sheep wool insulation is wonderful compared to traditional fiberglass or rock wool insulation. Rock wool is the worst to handle and I always suit up in coveralls and safety glasses before I touch it. Despite those precautions, I feel itchy even after a shower. The new improved fiberglass insulation I’ve handled causes a tiny bit of itching but really isn’t bad. Sheep wool insulation is the only one I’ve installed in my pajamas and tank tops. There’s no itching! I just wish it was a little easier to cut.

So far, we are only using the wool insulation in the upstairs end walls. The inner layer of each end wall was framed in 2x3s so we can pull each batt in half to cover twice as much area. (Six inch thick sheep wool batts evenly tear into two three inch thick batts.) During the 3 years since we bought the wool bale, Lee forgot that it was intended for 16 on center, and he had the walls framed at 24 on center. This meant we had to cut each batt in half length wise and install them sideways. Lee used sheep shears to cut the bats in half.

I found the sheep shears hard to use, so I ended up using kitchen shears for trimming ends that were too long.

Once the wool bats were in place I tacked them up with a staple gun. The whole process was super easy, but time consuming.

The picture below is a finished end wall using the sheep wool insulation. Unlike most building products, it has a pleasant smell like a hay barn or a horse blanket.

We plan to use sheep wool insulation in a few other areas of the house, so we are going to have to track down another source for the batts.

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17 Responses to Installing sheep wool insulation batts

  1. Pretty cool!..or warm I guess depending upon the season..sorry for the BAAAA-d ( yes in a sheep voice) joke. Looks great. I know my parents have some unusual insulation in the houses they grew up in in my dads house growing up the walls were filled with seaweed. Not really a high insulation value but it was better than nothing ( in the old days!). Coming along..nice to do work in flipflops rather than being cold!..your drapes from the first shot also being back memories for us..our old curtains looked the same!

    • lee says:

      Ha ha, sheep jokes. Think ewe are funny, eh?

      I’ve never heard of seaweed as insulation, but I suppose if you bundled enough of it up it might work pretty good. Straw doesn’t have a very high R value per inch either, but straw bale houses can be very well insulated.

  2. Benita says:

    I just learned something new. I never even knew such a thing existed or that wool could be used for insulation. Well, I always said there was no such thing and a bad fleece, just a bad used of a fleece. I follow up with “some fleeces are meant to be mulch” and now I can add “or insulation.”

    You guys are the coolest people!

    • lee says:

      The farmer we bought this from told us we could use the waste pieces as plant mulch too. I thought that was a neat recycling and waste reduction option. I wouldn’t want most other insulation materials anywhere near my garden.

  3. I was going to say using old-fashioned materials to replace new-fangled is a baaaaaack-to-the future idea, but EGBeaver up there already made the sheep joke.

    Our house leaks like a sieve, and when we finally get around to insulating, I’d love to go this route. Plus, I love the idea that you cut wool insulation with sheep shears!

    • lee says:

      The other insulation material I’ve seen which seems similarly nice to work with is recycled jean batts. Our one remaining supplier for sheep wool insulation also carries the jean insulation, so some of that might find its way into our house as well for the sheer novelty factor.

      The sheep shears are quite the hand exercise. Perhaps it will be good practice for when we get actual sheep. (Poor sheep.)

  4. Ann says:

    That was really interesting. I hope you manage to find some more wool batts so you can close up those walls!

  5. Daniel o,donnell says:

    I’ve just spent two days installing Sheeps wool under my ground all went well, but now my downstairs smells like lots of sheep have set up home in it. I’m hoping someone can tell me that the smell dissipates over time??? And how long? My wife is not happy right now!!!

    • lee says:

      Our insulation smelled a bit like a barn when we first put it up too, but it’s gone now. I don’t know how long it took, but it was never a particularly strong smell. I’m kind of surprised that you can smell the wool through the floor at all, but I would expect it to dissipate in a few days.

    • Sune says:

      Great reading.
      I’m just curious. How long DID the smell last? And did your wife end up happy after all?

      • lee says:

        Smell is so subjective it’s hard to say. It probably lasted a month or so, but it was never really unpleasant. After that you would have to put your nose up to the insulation to still smell it. Note that we hadn’t drywalled the room yet. We are now using this room as a bedroom (with drywall up) and you can’t smell it at all.

  6. KJ says:

    I wonder how hard it would be to make your own? Is the wool treated with anything?

    • lee says:

      I believe it is treated with a Borax solution to improve it’s fire resistance and discourage insect activity. You could probably just stuff wool into your wall for similar effect, although the batts ensure a consistent density (and thus insulation value). I’ve read that wool insulation has been found inside of the walls of European homes which are hundreds of years old, so it’s a decidedly low tech system.

  7. John T. says:

    I just found your blog yesterday, and I like it. I too have the itch for farm living, and just bought 5.58 acres (closed the deal today).

    Now to the point: I didn’t know sheep’s wool insulation existed till I read your blog, and so tonight I did a google search for it, and found something that I hope you have taken precautions against. on, there is a thread about lots and lots of people who have started using sheep’s wool insulation, and have had it heavily infested with moths which destroy it and then come into the house to look for other things to destroy also. I truly hope you have yours treated with something that prevents the moths!

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