Q: Should you skim coat plaster?

• <div><p>You can skim coat plaster, but it&rsquo;s better to repair the plaster itself. A skim coat is a thin coat of drywall joint compound spread over the surface of a wall. The result is a flat finish that looks pleasing, but part of the appeal of plaster is its imperfections and aesthetic. Skim coating is best when limited to drywall applications. </p></div>

Question 1

What is the difference between plastering and skimming?

Accepted Answer

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Plastering and skimming are two different techniques for finishing walls. Plastering involves applying a thick layer of a plaster mixture—typically containing gypsum, lime, cement, sand, and water—to create a new surface. This process often requires multiple coats and is used for repairing significant damage or creating decorative textures. Skimming, on the other hand, is a technique that involves applying a thin layer of drywall compound or joint compound over an existing surface to smooth it out, covering minor imperfections, small cracks, or uneven textures for a polished look. Plastering is generally more costly and labor-intensive than skimming. Although some people use the terms interchangeably, they refer to different processes and materials.

Question 2

Should you skim coat plaster?

Accepted Answer

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You can skim coat plaster, but it’s better to repair the plaster itself. A skim coat is a thin coat of drywall joint compound spread over the surface of a wall. The result is a flat finish that looks pleasing, but part of the appeal of plaster is its imperfections and aesthetic. Skim coating is best when limited to drywall applications.

Question 3

How do I know if I have plaster walls?

Accepted Answer

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If your home was built before the 1940s and was not remodeled in the past 50 or so years, you probably have plaster walls. Aside from assuming, there are some practical ways to tell if you have plaster walls, including the following: If you knock on the wall and it feels solid, not hollow, if you can’t insert a thumbtack easily, if there are cracks that look like spiderwebs, or if your home has curved, arched, or swirled walls, doorways, or window openings.

If you have an unfinished basement or attic, you could examine the backs of any finished walls to check, too.

Question 4

What damages plaster?

Accepted Answer

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Plaster is a pretty tough surface, but it can still sustain damage from things like bumping against it, water issues, dampness, extreme humidity changes, and plain old age. Most plaster walls last hundreds of years and will only be taken down to the base layer when major repairs are required. Being cautious around the wall, not placing furniture against it, and ensuring stable humidity are all great ways to reduce possible damage.

Question 5

Can you speed up plaster drying times?

Accepted Answer

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Yes, you can speed up the time it takes for plaster to dry, but it's important to do so carefully to avoid issues like cracking or crumbling. Proper ventilation is key; open a window or use a fan to circulate air in the room. Heat can also accelerate drying, but be cautious, as too much heat can cause the plaster to dry too quickly and crack. Check the plaster's packaging for the recommended drying temperature and set the room's thermostat accordingly. While managing humidity is important, avoid using a dehumidifier, which can remove moisture too aggressively and result in crumbly plaster.