How to Patch a Hole in Plasterboard

By Mick — IDIY’s lead handyman.

Plasterboard repair is the home-owner skill with the highest “looks-impossible-but-isn’t” ratio. Whether it’s a doorknob hole, a kid putting a foot through the wall, or a removalist taking out a corner with a wardrobe — the fix is the same set of techniques scaled up or down. Our team patches dozens of holes a month and a properly done patch is invisible after paint. Here’s the method we use, sized by the hole you’ve got.

What you’ll need

A sharp utility knife and a sharp jab saw (drywall saw)
A small piece of plasterboard sheet (offcut from a hardware shop — $5 will do most jobs)
Setting compound (Cornice cement / Easy-Sand 45 sets fast — preferred for repairs over premixed)
A 100mm and 200mm taping knife
Paper drywall tape or fibreglass mesh tape
120 and 240 grit sandpaper, sanding block
A short offcut of timber batten as backing
Drywall screws (32mm)
Primer and your wall paint for finishing

Step 1: Match the method to the hole size

Three sizes, three methods. Pinhole to 5cm: filler only. 5cm to 15cm (doorknob hole): California patch or peel-and-stick metal patch. 15cm and bigger: cut-out and replace with a fresh piece of plasterboard. Doing a too-small fix on a big hole always cracks within a year.

Step 2: Small holes — clean, fill, sand, paint

Slice off any loose paper around the hole with a utility knife, fill with setting compound using a 100mm knife, leave proud, sand flat once dry, prime, paint. 15-minute job.

Step 3: Doorknob-size holes — California patch method

Cut a piece of plasterboard 5cm bigger than the hole on every side. Score and snap the back paper, leaving the front paper as a flange. You now have a small piece of plasterboard with a paper “skirt” around it. Stuff the patch into the hole — the small piece fills it, the paper skirt sits flush against the surrounding wall like a flange. Spread setting compound over the paper skirt with a 200mm knife, feathering wide. Two more coats once dry, sand flat, prime, paint.

Step 4: Big holes — cut a clean square first

Take a pencil and square. Mark a clean rectangle around the damaged area, well beyond any cracking. Cut along the lines with a sharp jab saw — go slowly, keep the cuts square. You now have a clean rectangular hole.

Step 5: Add timber backers behind the hole

Cut a piece of timber batten about 10cm longer than the hole height. Slip it inside the hole, hold it tight against the back of the existing plasterboard, and drive two screws through the wall into the batten — top and bottom — so it’s anchored. Repeat on the other side of the hole. You now have two timber backers spanning the hole.

Step 6: Cut a plasterboard plug to fit

Measure the hole and cut a piece of plasterboard a few millimetres smaller on each side so it slips in. Score the front paper with a utility knife, snap the board, snap the back paper — clean cut. Test-fit the plug into the hole.

Step 7: Screw the plug into the timber backers

Hold the plug in place and drive two screws into each backer. Screws should sit slightly below the plasterboard surface — not deep enough to break the paper, just dimpled. The plug should sit flush with the surrounding wall, not proud, not recessed.

Step 8: Tape the seams

Apply setting compound along each seam between the patch and the existing wall. Press paper drywall tape (or mesh tape if you prefer) into the wet compound, smooth flat with the 100mm knife. The tape is what stops cracking from showing through paint.

Step 9: Three coats of compound, each wider than the last

First coat: cover the tape, 100mm knife. Let dry. Second coat: 200mm knife, feathering wider. Let dry. Third coat: very thin, 300mm if you have one, feathering further still. Each coat dries faster (setting compound is genuinely 45 minutes; premix is several hours). Sand lightly between coats with 120-grit, final sand with 240-grit.

Step 10: Prime, paint — and patience for the texture match

Always prime before painting a patch. Bare compound absorbs paint very differently from primed wall and you’ll see it for years. Once primed, paint with the same wall paint, two coats, feathered into the surrounding area. If the rest of the wall has a roller texture, use the same nap roller for the patch — short rollers leave smoother finishes that don’t match a long-nap textured wall.

The Mick rule

Match the fix to the hole. Filling a 15cm hole with putty is the most common reason patches crack. Cut it square, back it with timber, screw a plug in. Twenty minutes more work and it lasts forever.

Got a patch that’s bigger than you can fit a square cut around — corner damage, plumbing-leak ceiling? Send us a photo.