I am stripping off wallpaper from an old Scottish building. Some of the walls have damage, and some of the plaster has a white hairlike fiberous material below. I found this before it was in a whitey orange sheet that was exposed where a doorhandle had hit the wall too hard and exposed the fibers below the plaster, I didn't think twice about it, I plastered over it.

Today I came across it again, and it suddenly occurred to me that this could be asbestos. Has anyone seen anything like this before? Note this is a very small section, so it is largely undisturbed.

Does this look like abestos, and if it is, for small sections like this, is it safe to plaster over it?

enter image description here

I clipped off part of it with a scissors and took it outside. Then at arms length I set fire to it with a lighter holding it with tweezers with a mask on. It fizzled. It didn't melt, nor did it catch fire, but the strands disappeared very quickly.

I then took a small sample of fibers and brushed them with tweezers bending them to see if they broke off, they did not, the fibers were springy and no amount of bending them caused the fibers to snap off.

I then inspected the fibers carefully and saw that all the fibers were of the same thickness. I tried to tug at the fibers using two tweezers and there was a very high tensile strength - the fibres didn't break under strain.

Has anyone see this stuff before? Does it look like asbestos? Is it safe to plaster over?

  • 1
    "Is it safe to plaster over?" It is plastered over already, correct? h2ouse.org/horsehair-plaster The internet can not tell you if it asbestos. Buy an asbestos test kit if you want to know for sure.
    – Alaska Man
    Dec 28, 2019 at 2:01
  • 1
    @alaska man I have rehabilitated a few walls with horse hair plaster. I see that I linked to the same page you posted in my answer. 0wl do you have any idea how old this building is?
    – Kris
    Dec 28, 2019 at 3:13
  • It's victorian so at least 100 years old. The masonry is so old, you can still see the marks from the pickaxes on the red stone blocks.
    – Owl
    Jan 7, 2020 at 17:37
  • 1
    It seems that asbestos was not in use in the 1920’s or before.Internet says 1930s-1950s came into use in residential construction.
    – Kris
    Jan 7, 2020 at 18:38

1 Answer 1


I am almost certain that it is horse hair. It was added to plaster as a binder in the old days This site gives a history of its use and answers a ton of questions you might have about it.

For starters :

Horsehair plaster, also known as lath and plaster, is typically found in older homes and homes of significant historical value. This practice is not commonly used today. In fact, drywall began replacing the process in the 1950s. However, you can still find a lot of homes with horsehair plaster. If you’ve never heard of horsehair plaster before, then you’re probably pretty confused. So, what is horsehair plaster? Why is it called horsehair plaster? Although there are different variations, the most common type of horsehair plaster is a mixture of lime, sand, plaster, and horsehair. Yeah, that’s right, horsehair. The horsehair that was used was from the mane and the tail of the horse. Horse hairs are long, strong, and when they’re mixed with plaster, they offer a lot of structural strength.

Still if you want to be positive it is not asbestos have it tested.

And if you need something else to worry about there is a possibility of anthrax contamination in old horse hair plaster!


  • 1
    Anthrax, excellent :) This DIY project keeps getting better ;)
    – Owl
    Jan 7, 2020 at 17:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.