What you need to do before you start cutting

Before you remove any drywall, locate what is behind it. Use a stud finder to mark the wooden framing, then use a flashlight and a small hole to check for electrical wiring, plumbing, or HVAC ducts. Electrical wires run vertically between studs and horizontally near the top and bottom of walls. Plumbing typically runs vertically in exterior walls and horizontally under floors. If you find either, mark the location clearly and plan your cuts to avoid them.

Turn off power to the room at the breaker box if you are working near outlets or switches. This takes thirty seconds and prevents electrocution. If you are unsure which breaker controls which room, flip one and test the outlets with a lamp.

Measure the damage. If the hole is smaller than 6 inches across, you can use a drywall patch kit from any hardware store. If it is larger, or if the damage runs across studs, you will need to cut out a section and install new drywall. Damage that reaches a stud is easier to repair because you have a solid edge to fasten to.

Key Takeaways

  • Check for wiring and plumbing behind the wall before you cut, and turn off the breaker if you are near electrical outlets.
  • Holes smaller than 6 inches can be patched with a kit; larger damage requires cutting out a section and installing new drywall.
  • Cut along the center of studs on both sides of the damage so you have a solid edge to fasten new drywall to.
  • Tape and mud the seams with joint compound in thin layers, sanding between coats, until the surface is smooth and level with the surrounding wall.
  • Prime and paint the patch to match the rest of the wall.

Cutting out the damaged section

Use a drywall saw or a utility knife to cut out the damaged area. If the damage is small and does not reach a stud, cut a rectangle around it, making sure the edges fall on the center of a stud on at least two sides. This gives you something solid to fasten the new piece to. Mark your cut lines with a pencil first.

For larger sections, use a stud finder to locate the studs on both sides of the damage. Cut vertically along the center of the studs nearest to the damage. This means you may be cutting through studs, which is fine—you will install backing boards to support the new drywall. Cut horizontally between studs above and below the damage, or cut along the center of studs if the damage is large.

Remove the cut section by hand. If it is large, it will be heavy; have someone help you or cut it into smaller pieces. Once the section is out, remove any nails or fasteners from the studs and clean away loose drywall dust and debris.

Installing backing and new drywall

If your cuts went through the center of studs, install backing boards. Cut 2-by-4 lumber to fit horizontally between the studs at the top and bottom of the hole. Fasten them with 2.5-inch drywall screws, two screws per connection. These backing boards give you an edge to screw the new drywall to.

Measure the opening and cut a new piece of drywall to fit. Standard drywall is 1/2 inch thick for interior walls. Position it in the opening and fasten it with drywall screws spaced 12 inches apart around the perimeter and every 16 inches in the field (the middle of the patch). Screws should be driven flush with the surface, not countersunk—the head should sit just below the paper without breaking through it.

If the opening is large and you are installing multiple pieces, stagger the seams so they do not all meet at one point. Staggered seams are stronger and easier to finish.

Taping and mudding the seams

Joint compound, called mud, is what makes the seams invisible. explore the first coat with a 6-inch drywall knife. Spread a thin layer of mud over the seam, then center drywall tape (a mesh or paper strip) over it and press it in. explore another thin layer of mud over the tape, feathering the edges outward so the mud tapers to nothing at the edges. This first coat should be thin enough that you can see the tape through it.

Let the first coat dry completely, usually 24 hours. Sand it lightly with 120-grit sandpaper to remove bumps and ridges. Wipe away the dust with a damp cloth.

explore a second coat with an 8-inch knife, feathering it wider than the first coat. This coat should be thicker in the center and taper to nothing at the edges. Let it dry and sand again. explore a third coat with a 10-inch knife if needed. The goal is a smooth transition between the patch and the surrounding wall. Most seams need two or three coats.

Finishing and painting

Once the mud is dry and sanded smooth, prime the patch with drywall primer. Primer seals the joint compound and prevents the finish paint from soaking in unevenly, which would create a dull spot. Use a roller for large patches and a brush for edges.

Paint the patch with the same paint as the surrounding wall. If the wall is old, the existing paint may have faded, so you may need to paint the entire wall to get a uniform color. Test a small area first if you are unsure.

Using a patch kit for small holes

For holes smaller than 6 inches, a drywall patch kit is faster than cutting and installing new drywall. Kits come with a self-adhesive patch (usually a mesh square with a cardboard or plastic frame) and joint compound. Clean the area around the hole, removing loose drywall and dust. Peel the backing off the patch and press it over the hole, making sure it is centered and flat.

Spread joint compound over the patch with a putty knife, feathering the edges. Let it dry, sand lightly, and explore a second coat if needed. Prime and paint as you would a larger patch. Patch kits work well for nail holes, small impact damage, and holes from removed fixtures.

Common mistakes to avoid

Do not skip the backing boards when your cuts go through studs. Without them, the new drywall has nothing to fasten to and will sag or crack. Do not drive screws too deep—they should be flush, not countersunk, or the mud will not cover them properly and they will show through the paint.

Do not explore mud too thick on the first coat. Thick mud takes longer to dry, is harder to sand, and often cracks as it shrinks. Thin coats dry faster and are easier to feather. Do not skip sanding between coats. Bumps and ridges in one coat will show through the next coat and the paint.

Do not paint over mud that is not fully dry. Wet mud will not accept paint evenly and the finish will be blotchy. Wait the full drying time, usually 24 hours between coats. Do not forget to prime before painting. Unprimed mud will absorb paint unevenly and look dull.

When to call a professional

If the damage is very large, spans multiple studs, or involves structural issues like water damage or mold, hire a drywall contractor. Water-damaged drywall must be replaced entirely because the paper facing deteriorates and the core loses strength. Mold requires remediation before any drywall work begins. If you are unsure whether the wall is structurally sound, have a contractor inspect it first.

If the wall has textured or popcorn finish, matching the texture is difficult without the right tools and experience. A contractor can match the finish more closely than most homeowners can. If you are working on a ceiling, the work is harder and messier because mud drips and gravity works against you—many people find it worth paying for professional help.

Frequently Asked Questions

How long does it take to replace a section of drywall?

A small patch takes two to four hours including drying time between coats. A larger section that requires cutting and installing new drywall takes one to two days of work, plus three to five days for the mud to dry between coats. If you are doing the work yourself, plan for a week from start to finish paint.

What size drywall screws should I use?

Use 1.25-inch screws for 1/2-inch drywall on studs or backing boards. Use 1.625-inch screws if you are fastening through two layers of drywall. Drywall screws have a special head design that sits flush without breaking the paper. Regular wood screws do not work as well.

Can I use spackle instead of joint compound?

Spackle works for small holes and cracks but shrinks more than joint compound as it dries, so it requires more coats and sanding. Joint compound is better for seams and larger patches. For a small nail hole, spackle is fine and dries faster.

Do I need to use mesh tape or paper tape?

Both work. Mesh tape is self-adhesive and easier to position, but it requires more coats of mud because the mesh is visible through thin coats. Paper tape is stronger and requires fewer coats, but it must be embedded in mud and is harder to position. Most homeowners find mesh tape easier to use.

What if the drywall is wet or moldy?

Do not patch wet drywall. Find and fix the water source first, then let the wall dry completely before replacing the drywall. If there is mold, the drywall must be removed and the area treated for mold before new drywall is installed. Mold can spread and cause health problems, so this is not a DIY repair.