Using Local Sheep Wool as Natural Insulation

More than two years ago, I started researching insulation for the house my partner and I are building. At that point, we needed insulation for our earthen roof.

At the time, I was interested in hemp insulation, but I also spent a lot of time weighing sheep wool. In the end, we chose mineral wool because it was cheaper and easier to get.

We still need insulation for the attic and interior walls, and sheep wool kept coming back into the conversation.

The only U.S. company I could find making sheep’s wool insulation was Havelock, based in Nevada. They bring in fleece from New Zealand. It feels unnecessary to ship wool across the world when local sheep farmers have fleece they often end up discarding.

When I was deep in the insulation research process, we even thought about buying local wool and turning it into insulation ourselves. I usually do not hesitate to take on a do-it-yourself project, especially one that is environmentally friendly, but in this case I was the one who initially said no. My partner, who is not usually drawn to crafts or tedious work, unexpectedly supported the idea and said we should look into it.

We later returned to the idea of buying insulation, and then once again decided on mineral wool. Now, however, we have shifted back to sheep wool, and both of us are fully committed to the DIY insulation route.

After hearing a segment on NPR about Appalachian sheep farmers and Virginia Tech professors working to develop sheep wool insulation from a by-product of local meat sheep farming, I emailed one of the farmers interviewed in the report.

I hoped there might already be a prototype we could buy, but the project was still early. The farmer did, however, say he had plenty of wool to share and passed along the contact information for the Virginia Tech professor he works with.

I called the professor, and he offered advice on preparing the wool. He said he washed the fleece twice in hot water with dish soap, taking care not to agitate it, and then rinsed it again with plain water. After cleaning, he recommended air-drying the wool and then using a picker to fluff it up, since more trapped air makes the material better at insulating.

We also talked about adding borax to the final rinse to help keep pests out of the insulation.

Even though I know the amount of work involved will be enormous because of how much we need, the project still seemed possible.

We have been thinking through different ways to handle the washing step, from cleaning the fleeces in a bathtub to gathering stream water and organizing a fleece-washing work session with friends so we can process large quantities at once.

To insulate our attic, we will need just under 2,000 square feet of fleece at a depth of eight inches. I do not know how many sheep fleeces that would take, but I hope to find out in the coming weeks.

The instructions for Havelock’s loose-fill wool insulation say to stretch netting over the area being insulated and then use a blower to place the fluffy wool inside. Because it traps more air between the fibers, loose fill offers a better insulation value than batts.

I am trying to stay realistic and not get too hopeful about the sheep wool plan, since we may still have to go back to a previous option. Even so, I am excited to try this approach and to keep my family warm with natural, locally sourced materials.