Can You Caulk Drywall Corners?

Taping and mudding drywall corners requires time, skill, and patience. So, unless hanging drywall is your favorite task, you probably want to get it over with and move on. Wouldn’t it be faster to squeeze some caulk into the corner joints rather than do all the other stuff?

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You can caulk primed drywall inside corners with acrylic latex caulk to fill tiny gaps in less visible locations. However, most drywall applications use mud and tape to secure the joints properly and create a more workable surface.

This article will explain why drywall tape and mud make better inside corners, when to use caulk with drywall, and why caulked corners perform worse than tape and mud in most situations.

Can You Use Caulk for Drywall Corners?

You can use caulk for drywall corners in small, less visible areas, provided they’re primed first. Still, you risk sacrificing structural integrity and durability.

Suppose you plan to use caulk on your corners. In that case, I recommend Dap Acrylic Latex Plus Silicone (available on Amazon.com). It sands easily and stands out less when painted. Plus, the added silicone improves flexibility and shrink resistance.

When to Use Caulk for Drywall Corners

An inability to use caulk for finishing corners does not preclude you from using any caulk for sheetrock-related work. The following situations are generally considered acceptable for caulk.

After priming the drywall. Drywall requires priming before it can accept paint. This is because the absorbent wall surface absorbs paint, which messes up the paint job and makes the sheetrock swell. Some painters use caulk to round out corners and soften the room.

To fill small gaps and cracks. Minor cracks and gaps at or under ⅛” (3.18 mm) accommodate caulk, but it must be paintable, sandable, and resist shrinking.

On small sections in less visible areas. No one sees the bottom of the closets, and they aren’t typically prone to moisture issues that could threaten the latex. Caulk won’t give you the same holding strength or visual continuity as mud, so use it sparingly.

In dry, painted corners. For cracks in the paint of corners made with drywall, paintable caulk works well for touch-ups. However, a more sandable and paintable spackle is better suited to this purpose.

For repairing drywall with spackle, I use Red Devil Onetime Lightweight Spackling (available on Amazon.com) because you don’t need to sand it, and it doesn’t shrink. You can apply it and paint on the same day, saving you time.

Why Not Caulk Drywall Corners?

You cannot use caulk for drywall corners as a replacement for tape and mud because caulk does not secure the joint very well, last as long, or finish the same way. The results wouldn’t look as clean or streamlined.

Caulking should not be your primary method for finishing inside drywall corners. It only works for very small gaps and doesn’t have the holding ability of tape and mud. It’s too time-consuming and unrealistic to cut sheetrock to fit every space perfectly. Still, you can keep gaping to a minimum and have clean results without resorting to caulk.

Mud and tape create a more consistent, evenly sanded, durable, paintable corner. Switching between joining methods invites inconsistency in the work because, even though caulk and mud cure in the same amount of time (24 hours), they don’t cure into comparable final states.

This results in different surfaces for the paint to adhere to and mask, which is noticeable because the surfaces reflect light differently, with caulked areas appearing noticeably shinier. This condition is often referred to as flashing. While some high-quality acrylic caulks mitigate high sheen spots, they still appear different from adjacent surfaces.

Priming is not required until after taping and mudding. That’s because mud is evened out by feathering or smearing thinly to blend with the drywall surface, so no lines show through the paint. As a result, it is invisible behind the primer.

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Tape and Mud Perform Better Than Caulk

Taping drywall joints (where two sheets meet) secures the sheets together and acts as a barrier between the joint compound (mud) and the joint gap (space between sheets). The mud helps the tape bond to the drywall, strengthening the connection and eliminating as many gaps as possible.

This bond protects against cracks in the paint by keeping the walls and joints rigid. Settling structural elements and swinging temperature and humidity levels cause the house to shift, expand, and contract, which can cause cracks in the walls. Taped and mudded joints create a uniform surface able to withstand these stresses better than caulked joints can.

The drywall compound dries to a sandable and paintable hardness that blends into the surface, making the wall and compound indistinguishable. Caulk dries to a flexible and smooth gloss that doesn’t match the textured consistency of its surroundings.

Siliconized acrylic caulk is flexible but can still shrink when it dries, leading to cracks and gaps as it pulls away from the drywall. Adding a new caulk to fill these gaps adds bulk to the otherwise streamlined corner. Furthermore, the caulk is more likely to fail before drywall does, meaning more noticeable cracks and more frequent replacement.

Learning how to tape and mud is acquired through practicing well-informed techniques. To make it far easier, check out this helpful and time-saving video showing you one of the best ways to finish your drywall corners:

Conclusion

Caulk isn’t suitable for finishing inside corners. You can caulk drywall corners under specific circumstances:

For small, invisible joint sections
For minor corner touch-ups in visible areas
For filling small cracks
After priming

You will save a little time using caulk for small spots. However, you lose more quality than you gain in time, especially for larger areas. The results won’t be as structurally sound or as visibly pleasing, plus you sacrifice durability and longevity.

With video help and some practice, you will learn to quickly tape and mud straight inside corners that will look good and last decades.