Horsehair Plaster

Being at an age where I find myself more and more often starting sentences with the phrase “When I was growing up…”, sometimes coming across different items that we tackle on a day in and day out basis truly reminds me of something that I recall from “When I was growing up” which stuck with me for some reason back then and when I think back with what I know today, could definitely have been helpful to know!

One of these such items is a hole in the wall right behind a set of bunk beds which I shared with one of my brothers.

This hole seemed to resonate with me as the more something or someone touched it, the larger it seemed to get.

Not only that, but behind the hole was a series of wood slats, the hole did not seem to open up into some type of cavernous area behind it.

On top of this, I clearly remember some type of “fuzzies” being mixed in with the material the wall was made out of.

Unbeknownst to me at the time, the product that our walls were made out of was horsehair plaster.

Horsehair plaster is made out of varying combinations of water, lime, plaster, sand, and animal hair – you guessed it – most often horsehair.

Sometimes the hair from other animals such as oxen, donkeys, and goats was utilized instead of horsehair.

Plants such as hemp, jute, reed, and straw have also been known to be used in place of the animal hair, the challenge with the fibers from plants such as these though is that it is not as strong as the hair from the animals due to the protein-based qualities of the animal providing a stronger, more durable finish.

Horsehair was the “go to” plaster for many years by many builders because it was so flexible in comparison to the other types of animal hair and plant fibers and the finish was much more uniform.

These days, horsehair plaster is rarely utilized.

In fact, there are few practicing tradespeople around that even know how to make it, never mind work with it once it is made.

From a historical preservationist standpoint, some jobs actually require horsehair plaster repairs to be conducted with actual horsehair plaster however, as the scopes of certain types of historical preservation projects require for the project being done to utilize all building materials that are as closely in-line with what was originally used as possible.

We are called on occasion to repair old horsehair plaster walls, such as the one mentioned from when I was growing up, utilizing modern day repair methodologies.

If we were called in today to repair the hole that was behind my bunk bed as I was growing up, the first thing we would do would be to carve out any of the loose plaster around the hole.

We would keep going until the perimeter of the hole was as stable as possible.

From there we would most likely stabilize the perimeter by screwing in plaster washers (see blog here: https://lopcocontracting.com/a-trick-to-fixing-frustratingly-stubborn-plaster-failures/) around the actual hole.

Then we can cut a piece of drywall to fit as snugly into the hole as possible, tape the perimeter and any related seams with fiberglass mesh tape, and then utilize joint compound to work the plaster repair from there (apply the joint compound to seams and perimeter, sand when dry, repeat until hole meets optimum smoothness).

After the repair is complete, things can be prepped, primed, and painted to the desired finish.

Although not old enough to have “When I was growing up…” translate into a phrase which includes the actual common utilization of horsehair plaster in daily plaster operations, I am still old enough to remember the time when horsehair plaster and its associated repair challenges were much more commonplace than they are today, due to the overall percentage age of the housing where horsehair plaster would be more likely to be found being diluted with newer constructed homes and their associated more modern day building methodologies which – shockingly – do not include horsehair plaster being used on a normal basis.

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