Horsehair Plaster Repair: How to Repair Crumbled Plaster

broken plaster wall
  • 24-48 hours
  • Intermediate
  • 150-200
What You'll Need
Plaster of Paris or other setting compound
Dust mask
Work gloves
Plastic sheeting
Utility knife
Wire mesh
Wire cutter
Sand paper

Horsehair plaster was applied in the interior partition walls, together with an ornamental texture on the surface of homes built in the U.S. prior to the late 1950s. The laths are usually 2 inch by 4 foot long wooden strips that are usually 1/4 inch thick; these are nailed to a wall frame. Horsehair plaster was also used in the first half of the twentieth century; it is a regular plaster which includes horsehair fibers to strengthen the mix. A repair of the horsehair and crumbled plaster should be done carefully to preserve the historical value of the home; the procedure is not difficult. Here are some helpful tips:

Step 1 - Look for the Signs of Disrepair

Many older houses have withstood temperature changes over time; this brings moisture to the plaster. As such, if your walls show dampness, peeling, brown stains or deformities, a repair is required.

There are also instances of cracking on the surface; this is usual for old plaster walls. Larger cracks particularly those around the door frames or windows should be referred to experts since it might be a sign of that structural damage is occurring to the house.

Step 2 - Take the Necessary Safety Precautions

When doing the repair, remember that old plasters contain harmful chemicals such as lead. For this reason, you must keep children and pets away from the area; it is unsafe to breathe the dust. It is therefore necessary to wear a dust mask when working with old plaster. You should protect surrounding areas with plastic sheeting.

Step 3 - Deal with the Cracks Carefully

When you are dealing with cracks, avoid using drywall mud or spackle paste, instead use a setting compound to give a more lasting restoration in your project. Fill the setting compound in the cracks. Use a pointed tool along the crack so that the compound is spread evenly and thoroughly to strengthen the spot.

Step 4 - Check the Hole before Applying the Plaster

When repairing a hole in the plaster, check if the wall has a backing to hold the plaster from the back. If not, you have to install the backing first before repairing the holes. To do this, press on the wire mesh to the hole and hold it with wire ties around one or two rod of sticks. Apply the plaster and let it dry. Then, cut off the wire ties.

Step 5 - Finishing Touches

Use wet sponges to even out the repaired surfaces; this will make the walls reasonably smooth. After your repair work, meticulously clean the area.