To patch a hole in drywall, match the repair to the size of the hole: fill small holes with lightweight filler, cover medium holes with a self-adhesive mesh patch and joint compound, and replace a cut-out square of board for large holes. In every case, thin coats, full drying time and careful sanding make the patch disappear under paint. Drywall is called plasterboard in the UK, and the same methods apply.
Table of Contents7 sections
What You Need Before You Start
Most drywall repairs need only a utility knife, filling knives, filler or joint compound, a sanding block, primer and paint, plus a mesh patch or a drywall offcut for bigger holes, and you may have several already. Gather everything first so you aren’t hunting for a scraper while the compound dries.
| Tool or material | Used for |
|---|---|
| — | — |
| Utility knife | Trimming loose paper and cutting out damaged board |
| Filling knives (narrow and wide) | Applying and spreading filler or compound |
| Lightweight filler or spackle | Nail holes, dents and small holes |
| Self-adhesive mesh patch | Medium holes, roughly door-handle size |
| Joint compound | Covering patches and seams |
| Offcut of drywall and a drywall saw | Large holes |
| Fine sanding block or sponge | Smoothing between coats |
| Dust mask and safety glasses | Protection while cutting and sanding |
| Primer and matching paint | Finishing |
Safety Checks Before You Cut or Sand
Check what is behind the wall and what the wall is made of before you cut anything. A few minutes here prevents the expensive mistakes.
Cables and pipes
Electrical cables and water pipes often run inside walls, commonly straight up or down from sockets and switches, and horizontally near them. Use a detector to scan the area, and keep cuts shallow. If the hole is near a socket or switch, switch off that circuit at the consumer unit or breaker panel before you start. If you find wiring that looks damaged, stop and call a qualified electrician.
Lead paint and older walls
Older homes can hide hazards in the paint and the wall coatings. The US Environmental Protection Agency (EPA) says homes built before 1978 are more likely to have lead-based paint, and that renovation work which disturbs painted surfaces can release lead dust. If you must sand in an older home, the EPA advises wetting the area first, sanding as little as possible and cleaning up thoroughly.
Some older patching and joint compounds and textured paints contained asbestos. The US Consumer Product Safety Commission says their use was banned in 1977. If your home is older and the wall has a textured coating, don’t sand or scrape it. Have a professional check it first.
Water damage and mould
A hole caused by a leak needs the leak fixed first. Soft, stained or crumbling board is a sign of water damage, and patching over it won’t last. The EPA advises against painting or caulking over mouldy surfaces, and recommends professional help if mould covers more than about 10 square feet or the water damage is extensive.
How to Fix Small Holes
Small holes, such as those left by nails, screws and picture hooks, need only filler. This is the quickest repair and usually takes one or two thin coats.
- Press in any raised paper or burrs around the hole with the handle of your knife, so the surface sits slightly below the wall.
- Load a little lightweight filler onto a narrow knife and press it into the hole.
- Draw the knife across the hole at a low angle to scrape off the excess, leaving a flat surface.
- Let it dry according to the label. Lightweight fillers often dry quickly, but deeper holes take longer.
- Sand lightly until smooth, then add a second thin coat if the filler has shrunk.
For a row of holes, such as old shelf screws, fill them all in one pass with a wide knife.
How to Fix Medium Holes With a Mesh Patch
A self-adhesive mesh patch is the simplest fix for holes up to a few inches across, such as a dent from a door handle. The mesh bridges the hole, and joint compound builds the surface back up over it.
- Trim away loose paper and crumbled gypsum with a utility knife so the edges are firm.
- Sand the area around the hole lightly so the patch sits flat.
- Peel the backing off the patch and press it over the hole, centred, with the mesh overlapping firm board on all sides.
- Spread a thin coat of joint compound over the patch, extending a few inches past its edges. Feather the edges thin.
- Let it dry fully, sand lightly, and apply a second, wider coat. A third coat is often needed for a smooth finish.
Thick coats crack and take a long time to dry. Two or three thin coats, each slightly wider than the last, give a flatter result.
How to Fix Large Holes
Holes bigger than a mesh patch can cover need a new piece of board. This takes longer but is still a manageable DIY job.
- Draw a neat square or rectangle around the damage, keeping clear of any cables or pipes you found.
- Cut along the lines with a drywall saw, using shallow strokes, and remove the damaged piece.
- Screw two strips of wood inside the hole, behind the wall, so they span the opening and overlap the existing board top and bottom. These are the backing strips that hold the new piece.
- Cut a piece of drywall of the same thickness to fit the opening and screw it to the backing strips, setting the screw heads just below the surface.
- Cover the joints with paper or mesh tape and a coat of joint compound.
- Let it dry, sand, and apply two more thin coats, feathering each one wider than the last.
If a large area is damaged, the board sags, or the hole is in a ceiling, consider calling a professional. Ceiling repairs involve working overhead on a ladder, and a heavy patch that falls can hurt someone.
How to Get an Invisible Finish
The patch disappears when it is flat, smooth and primed before painting. Hold a torch or lamp flat against the wall to throw light across the surface: any ridges or dips show up as shadows. Sand those down, or fill dips with one more thin coat.
Prime the patch before painting. Bare filler and joint compound soak up paint differently from the surrounding wall, which leaves a dull patch that shows through even two coats.
After priming, paint the whole wall section from corner to corner if you can. Touch-ups on a small area often show as a slightly different sheen, especially on older paint.
How Long Does Drywall Patching Take?
Small holes can be filled and painted in a day with a quick-drying filler, and on any patch most of the time goes on waiting for each coat to dry. Medium and large patches usually need two or three coats of joint compound, and drying times vary by product, room temperature and thickness. Check the label on your compound, and don’t rush the next coat over a patch that still looks darker or feels cool to the touch.