Question 1

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 2

What causes plaster damage?

Accepted Answer

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Common causes include water leaks, settling, and impact. Address underlying issues to prevent recurring damage.

Question 3

What is the difference between spackle and joint compound, and which should I use for drywall repairs?

Accepted Answer

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Although they have similar applications, spackle and joint compound are not the same. Their primary differences lie in their composition, consistency, and ideal use cases.

Spackle is composed of gypsum and binding agents, making it thicker than joint compound. It dries quickly and is easy to sand, which makes it ideal for small wall repair projects like filling nail holes or patching minor damage.

Joint compound, also known as drywall mud, consists of limestone and gypsum. It is primarily used for large-scale projects, such as taping and finishing the seams on newly installed drywall. It tends to shrink more than spackle and can be more difficult to spread.

While both products can be used to fill small depressions and cracks, spackle cannot replace joint compound for taping and mudding new drywall. Conversely, you can often use joint compound for small patching jobs typically done with spackle.

Question 4

Can you mix plaster types?

Accepted Answer

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You can put certain types of plaster over other types, but doing so isn't always the best idea. For example, putting a coat of gypsum over lime plaster is possible, but doing so will limit the lime plaster's breathability and potentially affect its performance.

Since cement plaster tends to leave a textured surface, no matter how much you smooth it, some people prefer to use gypsum plaster as a topcoat over cement plaster, creating a smoother surface.

Question 5

Can I just paint over hairline cracks in plaster?

Accepted Answer

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You can technically just paint over hairline cracks in plaster since these cracks are often harmless, but this will mostly be a waste of paint. Paint will only hide the hairline crack for a few months before it shows up again. The best solution is to repair the crack with flexible filler or joint compound before repainting.