Anybody know what kind of blown-in insulation this is?
![](https://secure.gravatar.com/avatar/b5e46fa8bf0fd21d824dc938a1d1c6ce?s=52&d=https%3A%2F%2Fimages.greenbuildingadvisor.com%2Fapp%2Favatars%2F200x200%2Fm.png&r=g)
My attic floor was insulated with about 3-4 inches of this material, which I have never seen before. My first hypothesis based on weight and texture is finely shredded redwood bark, but I have never heard of that material’s being used as insulation. The attic was probably insulated between 1970 and 1995.
Does anybody know what this is?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb1.png)
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb2.png)
Replies
It looks like wood fiber insulation. This link may be helpful: https://inspectapedia.com/insulation/Balsam_Wool_Insulation.php#BProp
Note that apparently one manufacturer incorporated asbestos into its production process.
Thanks Steve!