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

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 2

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 3

Can you use drywall repair techniques on plaster?

Accepted Answer

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Yes, you can use drywall repair techniques for some types of plaster damage. Tiny holes and small cracks in plaster can be patched in similar ways to drywall. You apply the necessary compound to fill the hole, wait for it to dry, then sand it down. For larger damage, like water damage or mold, you need to use plaster-specific techniques and materials.

Question 4

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.

Question 5

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.