How to Fill Holes in Plasterboard

Plasterboard is the standard finish for modern interior walls, but despite its versatility, it is relatively fragile. Whether it is a screw hole from a moved picture frame, a doorknob dent, or a large accidental puncture, damage is inevitable.

Fortunately, repairing plasterboard is a straightforward skill to master. The method you choose depends entirely on the size of the damage and the type of wall construction (stud partition vs. dot and dab masonry).

In this guide, we will walk you through the professional methods for repairing everything from hairline cracks to large voids.

Materials You Will Need

Before starting, assess the damage and gather the correct supplies. You likely won’t need everything on this list for a small repair.

• Filler: For small holes, a tub of multi-purpose filler is fine. For larger joints, powdered jointing compound is stronger.

• Plasterboard Patch: An offcut of plasterboard (Standard 12.5mm is most common) for patching larger voids.

• Timber Batten: A small offcut of wood to act as a brace behind the wall.

• Sanding Block: 120-grit sandpaper is usually best for a smooth finish.

• Filling Knife / Trowel: A broad blade helps feather the edges.

• Drywall Screws: We stock both Coarse Thread Drywall Screws (for timber studs) and Collated Drywall Screws depending on your tools.

• Fibreglass Mesh Tape: Essential for preventing cracks around a new patch.

• Utility Knife: For squaring off damaged edges.

• Wire/Stud Detector: Safety first—always check for live cables before cutting into a wall.

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Scenario 1: Small Holes (Nails, Screws, and Rawlplugs)

Best for: Holes less than 10mm wide.

Small holes are purely cosmetic repairs. The structural integrity of the wall is fine; you just need to restore the surface.

1. Clean the Hole: Often, pulling out a Rawlplug pulls the paper surface out with it, creating a “lip.” Use the handle of your filling knife or a screwdriver to gently push the edges of the hole inwards, creating a slight dent. If there are loose paper tags, cut them off with a knife.

2. Fill: Press a flexible filler into the hole. Don’t just wipe it over; push it in to fill the void.

3. Proud Finish: f using standard filler, leave it slightly “proud” (raised) as it often shrinks when drying. However, if you use a lightweight product like One Strike Filler, you can smooth it flush with the wall immediately as it resists shrinking.

4. Sand: Once dry, gently sand flush with the wall.

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Scenario 2: Deep Damage to Masonry (Dot & Dab Walls)

Best for: Walls where the plasterboard is stuck to brick, and the damage goes right through to the blockwork.

If you have a “Dot and Dab” wall, there is a small cavity between the board and the brick. Sometimes, heavy impact or removing a socket box damages the brickwork behind the board.

In this instance, standard filler is often too soft to build up deep layers. Professionals will often use a backing plaster like Thistle Bonding Coat to bulk fill the damage. Alternatively, you can inject a small amount of Soudal expanding foam into the deep void. This expands to fill the gap and insulates the cold spot; once hardened, simply cut it back to create a stable base for your surface filler. You can finish the final few millimetres with a fine surface filler or skim.

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Scenario 3: Large Holes (The “Backing Batten” Method)

Best for: Fist-sized holes or damage where there is a hollow void behind the board.

You cannot simply fill a large hole with filler – it will just fall into the wall cavity. You need to insert a new piece of plasterboard. The challenge is: what do you screw the new piece to?

Step 1: Square Off the Damage It is impossible to cut a patch to fit a jagged, accidental hole. Use a spirit level to mark a square or rectangle around the damage, and cut this section out cleanly using a pad saw or sharp utility knife.

• Tip: Check for wires with a detector before cutting.

Step 2: Prepare the Backing Cut a length of timber batten (approx. 50mm x 25mm) that is slightly longer than the height of your hole. Insert this piece of wood into the hole. Hold it tight against the back of the existing plasterboard, spanning across the opening.

Step 3: Fix the Batten While holding the timber tight against the back of the wall, drive drywall screws through the existing wall face and into the timber. Sink the screw heads slightly below the surface. You now have a solid piece of timber fixed firmly behind the hole.

Step 4: Insert the Patch Measure your square hole accurately. Cut a fresh piece of plasterboard to fit the gap. Place it into the hole and screw it into the timber batten you just installed. The patch should now be flush with the wall.

Step 5: Tape and Fill You will now have seams around your patch.

• Apply self-adhesive mesh tape over the seams. This reinforces the joint and stops the filler from cracking later.

• Apply a coat of jointing compound/filler over the tape. Spread it wider than the patch (feathering) to blend the repair into the wall.

Step 6: Sand and Paint Once dry, sand the area smooth. You may need a second thin coat of filler to remove imperfections. Prime the area with a mist coat (watered-down emulsion) before painting to ensure the paint adheres evenly.

Conclusion

Whether it is a tiny screw hole or a large accident, the key to a good repair is preparation. Don’t rush to fill a hole without preparing the edges or installing a backing support, otherwise, the repair will crack or sink within weeks.

If the damage to your wall is extensive or covers a large area, it may be more cost-effective to replace the entire sheet. You can view our full range of Plasterboard and Drylining supplies here.