While screwing in an electrical cover in my new home (built in 1919) I noticed these fibers sticking out of the plaster or skim coat. I have not seen these anywhere else. Hope the picture loads. Are these asbestos fibers?enter image description here

  • 3
    1919, and that large - more likely horsehair.
    – Ecnerwal
    Mar 7, 2015 at 19:46

1 Answer 1


Often, people talk about “old-fashioned horse-hair plaster,” but the binding agent in old plaster walls was more commonly cattle hair. -searshomes.org

enter image description here

I am reasonably sure it's not asbestos.

  • 1
    Agreed, because the fibers are longer than you'd expect from asbestos, plus the timeframe makes it unlikely. From stucconews.net/column/asbestos.html , "... Before the 1920's, most basecoat plaster in residential use was lime and sand, and not gypsum plaster. It is doubtful that a horse and wagon plasterer would go out of his way to find manufactured asbestos fibers to put in lime plaster." Mar 7, 2015 at 19:51
  • I agree - asbestos stuff is really flaky and brittle. I have gutted out a lot of asbestos in my life and never seen anything with those hairs.
    – DMoore
    Mar 7, 2015 at 23:13
  • What's the substance in your picture here? Is it cattle hair or asbestos? I've knocked out a bit of old crumbling plaster from our wall and noticed some hairs in it. This picture here is the closest example I've found to what I saw in my walls. I have no idea how old our house is. The records don't seem to be conclusive. the earliest record we can find is around '65 but the style is Edwardian which indicates an earlier date.
    – jeanaux
    Jun 12, 2018 at 18:13

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