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How to Restore Old Plaster Ceiling

Cracks or loose pieces of plaster on your ceiling often appear because of broken plaster keys. If you do not restore the plaster in a timely manner, the ceiling may collapse.

The pictures and comments below illustrate steps that need to be taken during restoration of old plaster ceilings.

The ceiling on the picture below (Picture 1) is at the beginning of restoration.

Picture 1

On the right, in the back, you can see the gray area. Here, loose or sagged top coat of old plaster and all the layers of paint were removed from the ceiling. In the brown part, old plaster was still good but the paint was old and weak. It was scraped off. The white part of the ceiling was left untouched as it was found in a good condition.

You can see how the entire surface of old plaster was chipped. This needs to be done for better connection with new material. If new plaster is applied without chipping, layers of old paint or top coat of old plaster could split and fall down together with the new plaster. The second picture (Picture 2) shows another, and a more difficult, case.

Picture 2

The old plaster topcoat was removed from the entire ceiling surface. It had to be done because the topcoat was applied onto a layer of weak brown plaster that has high sand content. To make old brown plaster stronger, a coat of bonder, like Plaster Weld, needs to be applied.

On the same picture, on the right side, you can see laths showing. Here, old plaster was sagged or crumbled due to broken keys or loose laths. It had to be removed. The third illustration (Picture 3) shows a ceiling with similar problems. There are laths showing and the topcoat fell off in two gray colored areas.

Picture 3

This old ceiling plaster had lots of very thin cracks. They all need to be scraped and made at least ¼" deep in preparation to filling them with new plaster. If they are not made wider and deeper, they will reappear on the new ceiling.

Before applying a new coat of plaster we strongly recommend to screw in Plaster Washers in all beams about 8 inches apart (also illustrated on Picture 4). They will secure plaster and laths. This also has to be done next to the cracks (see Picture 5). For a 15 by 15 feet ceiling you will need approximately 250-300 washers.

Picture 4

Picture 5

Picture 6

After washers are installed, a bonder is applied (please refer to Picture 6). Bonders, like Plaster Weld, tighten up old plaster surface and provide for a better connection with new material. The places where old plaster was removed till laths are filled with new base and stretch coats. To cover the washers, a new base coat of plaster is applied. While it is still wet, we install a heavy fiberglass mash followed by a topcoat of plaster.

After the plaster gets dry, the paint is applied. The result is the flawless ceiling below (Picture 7).

Although restoring plaster ceilings is far from easy, it returns beauty and solidity of old plaster.

Picture 7