Before painting a room, it’s important to repair any cracks, dents, or other flaws in the drywall. To make it easy to see flaws in a wall, hold a strong light against the wall and shine it across the surface.
Types of Joint Compound
Joint compound is available premixed in buckets, which take 12 to 24 hours to dry after application. Premixed joint compound dries ay evaporation, so apply thin coats and allow each coat to dry before applying more.
Joint compound is also available as a fast setting powder, which cures by chemical action in 20 to 30 minutes after it is mixed with water. Both types of joint compounds should be mixed thoroughly until smooth before applying.
Minor Drywall Repairs
To repair dents, small cracks, and other minor defects in drywall, apply joint compound to the wall using a drywall knife or wide putty knife.
After the joint compound has dried, apply additional coats until the defect is filled.
Sand the hardened joint compound with medium grit sandpaper using a flat sanding block or pole sander until the repair is smooth and flat. Be sure to wear an approved dust mask when sanding drywall.
Repairing Larger Cracks
For larger cracks or defects, apply joint compound to the wall, then cover the crack with paper drywall tape pressed into the wet compound. Cover the tape with more joint compound, and allow it to dry before sanding.
Watch this video to find out more.
- How to Repair Damaged Drywall (video)
- How to Repair a Ceiling Crack (video)
- How to Repair Cracks in a Drywall Ceiling (article)
- How to Repair a Popped Nail in Drywall (video)
- How to Patch a Hole in Drywall Using a Hot Patch (video)
Danny Lipford: If you’re going to repaint a room, you may as well take the opportunity to repair any flaws and cracks in the drywall before you apply the new color. To do this you’ll need drywall joint compound, a drywall knife, and a “mud pan,” which is a rectangular box that allows you to scrape excess compound from the knife blade.
Pre-mixed joint compound typically takes 12 to 24 hours to dry, and many repairs will require multiple coats, so you may want to use “fast setting” joint compound, often called “20 minute mud.” It comes in powder form and is mixed with water.
Whichever compound you choose, you’ll want to mix it with your knife in the mud pan until it is a smooth, pliable consistency.
Nail holes and chips can be covered by applying a small amount of compound pressed into the void. Then drag the knife over the repair with firm pressure to remove excess material from the surface.
For larger cracks you’ll want to use paper drywall tape. First, apply mud to the crack, then press the tape into it with the knife to completely embed it. Once the tape dries, these repairs will need several more coats of joint compound applied with progressively wider knives to blend the repair into the surrounding wall. Firm pressure on the edges of the knife will reduce the amount of stray mud left behind.
The final step is sanding down the lap lines and imperfections to leave a smooth wall for painting.