Repairing Drywall Cracks In Corners

When I searched for articles on how to 'repair a bullnose rounded drywall corner', I was amazed there wasn't a good step-by-step article with clear instructions and pictures to make the repair process crystal clear. All I could find in the top search results were poorly written instructions without any pictures to make the steps clear and obvious. Texture Repairs. You can try to find a matching caulk that will cover the cracks as well as possible, or you can caulk the corner and cover it with a new layer of stucco. Understand that trying to match the exact color of dried stucco is very difficult, as there are numerous variations in mixing batches, manufacturers, dyes.

1. Repairing Drywall Cracks In Corners Foot
2. Repairing Drywall Cracks In Corners Of Mouth
3. How To Repair Sheetrock Cracks In Corners

Written by Chris Deziel; Updated December 10, 2018

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Inside drywall corners are a bit more difficult to finish than flat seams, and an inexperienced worker may fail to spread enough mud or to sufficiently scrape the tape. The result is tape that bubbles and separates. This problem isn't very difficult to fix, but you may have more trouble if cracks appear in the corners. Corner cracks often signify that the walls are shifting and will eventually reappear if you simply coat them with mud. Even if you can't stabilize the walls, you can fortify the drywall corners so they don't crack as easily.

Bubbling and Separating Tape

1. Cut out bubbles and separating tape with a utility knife. Cut away all the loose tape, leaving only tape that is still firmly attached to the wall.

2. Scrape off dry, loose joint compound, or mud, with a 4-inch drywall knife. It's important to remove all of it -- even small particles can cause streaking when you recoat.

3. Spread a new coat of mud over each damaged area. All-purpose, pre-mixed mud works well, but you can also make your own by mixing powdered joint compound with water in a bucket. The mud should be as thick as peanut butter.

4. Lay paper drywall tape over each repair. Dip the tape in water before you apply it to make it adhere and flatten better. Scrape the tape flat and recoat it immediately with mud. Scrape that mud flat and let the repair dry overnight.

5. Recoat once or twice more, using a wider knife to scrape each coat and progressively flatten the seam. Let each coat dry before applying the next, and sand the final coat with 120-grit sandpaper. Prime the repair with drywall primer before you paint it.

Cracks

1. Slide a paint scraper under a section of cracked tape and lift it, then pull off the tape. Scrape off all the mud from both walls forming the corner so you can lay new tape.

2. Prepare a small amount of setting-type, or hot, mud. Pour some powder into a mudding tray, add water and stir until it is lump-free and about the consistency of honey. You can mix it thinner than the non-setting variety because it doesn't shrink and is best applied in thin coats.

3. Spread the hot mud on both walls that form the corner with a 4-inch drywall knife. Cut enough fiberglass mesh drywall tape to cover the seam, crease it lengthwise and lay it on top of the mud. Spread another coat of mud on top of the tape and scrape it flat.

4. Let the hot mud dry completely, which takes from 6 to 10 hours, then recoat it with two or three coats of non-setting mud, scraping each coat flat and letting it dry before applying the next. Sand and prime the final coat before you paint it.

Things You Will Need

• Utility knife

• 4-, 6- and 8-inch drywall knives

• Non-setting mud

• Paper drywall tape

• 120-grit sandpaper

• Drywall primer

• Paint scraper

• Hot mud

• Mudding tray

• Fiberglass mesh tape

Tip

Both fiberglass mesh tape and hot mud resist cracking, so the combination should provide a permanent repair unless the shifting of the walls is extreme.

Hot mud is difficult to sand, so it's important to scrape it flat before it stiffens.

Warning

Determine the setting time of the hot mud by reading the instructions on the container and mix only as much as you can use in that time. Don't spread it if it begins to stiffen, and be sure to clean your tools and tray before it sets.

References (2)

About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.

Cite this Article

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Deziel, Chris. 'How to Repair Drywall Inside Corners.' Home Guides | SF Gate, http://homeguides.sfgate.com/repair-drywall-inside-corners-41595.html. 10 December 2018.

Deziel, Chris. (2018, December 10). How to Repair Drywall Inside Corners. Home Guides | SF Gate. Retrieved from http://homeguides.sfgate.com/repair-drywall-inside-corners-41595.html

Deziel, Chris. 'How to Repair Drywall Inside Corners' last modified December 10, 2018. http://homeguides.sfgate.com/repair-drywall-inside-corners-41595.html

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Gather your materials.

You’ll need a 6-inch taping knife, a 10- or 12-inch taping knife, 1 square piece of plywood or a plastic mud pan, drywall compound, drywall tape (paper or fiberglass), and fine-grit sandpaper and a sanding block.

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Clean out the crack.

Use your taping knife to scrape the edges of the crack to remove any dust.

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Put some compound on the plywood or mud pan.

This makes it easy to load onto the knife.

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Put some compound on the plywood or mud pan.

This makes it easy to load onto the knife.

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Apply a light coating of compound to the crack using the 6-inch taping knife.

Make sure that the coating is wet but not thick.

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Embed the tape in the compound immediately.

Lay the tape over the compound you just applied and use the knife to push the tape into the compound. If necessary, cut the tape in short lengths to follow the line of a really crooked crack.

If you bought fiberglass tape, you can skip the embedding coat of compound under the tape because it is self-sticking. Otherwise, you do everything the same way.

Warning: Fiberglass tape is thicker than paper tape, which makes it harder to repair invisibly.

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Scrape the tape with the wider knife to scrape away any excess compound.

Use a smooth scraping motion.

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Scrape the tape with the wider knife to scrape away any excess compound.

Use a smooth scraping motion.

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Apply a thin coat of compound over the tape using the 6-inch knife.

Be sure to feather the edges. Let the patch dry completely (usually overnight).

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After the first coat is dry, apply a second coat with the wide knife.

By using a wider knife, you blend out the original edges. Make sure to feather the edges again. Again, let it dry.

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Allow to dry and then apply a final coat.

Follow the same procedure as before.

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Allow to dry and then apply a final coat.

Follow the same procedure as before.

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Sand the patch until smooth.

Use a fine-grit paper to smooth out the surface.

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Repairing Drywall Cracks In Corners Foot

Paint over the patch with primer.

Don’t skip this step or you’ll end up with a permanently goofy-looking, non-matching area.

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Repairing Drywall Cracks In Corners Of Mouth

Apply touch up paint to the patch in your wall color.

How To Repair Sheetrock Cracks In Corners

This is why you saved that half a gallon of leftover wall paint.