How to patch a hole or dent in a plasterboard wall
The Abimeister team · Updated · 4 min read
Doorknobs, furniture corners and removed shelf brackets all leave their mark on plasterboard, and most of the damage is smaller than it first looks. A dent the size of a coin and a fist-sized hole call for different repairs, and getting that distinction right saves you redoing the work. This guide walks through judging the damage, the two main repair methods, drying and sanding, and the point where it makes more sense to have someone else do it.
How big is the damage, and can you fix it yourself
Plasterboard walls in Estonian flats are usually 9 to 12.5 millimetres thick, fixed to a metal or timber stud frame with a gap of air behind. A dent that hasn't broken the paper skin is cosmetic and easy to fix. A hole that goes all the way through, even a small one, needs backing material behind it or the filler has nothing to hold onto.
As a rough guide, anything up to about 3 centimetres across can usually be filled directly. Anything larger, or anywhere the edges are crumbling and soft, needs a patch of plasterboard behind it, not just filler pushed into open air. Check the area isn't near a socket, switch, or cable run before you start.
Fixing a small dent or hole with filler
For a dent, brush off any loose plaster dust and dampen the area slightly with a wet brush so the filler doesn't dry too fast and shrink. Apply ready-mixed plasterboard filler with a flexible filling knife, pressing it in rather than smearing it over the top, and leave it slightly proud of the surface.
For a hole up to a few centimetres wide, first push a scrunched piece of newspaper or a small offcut of plasterboard just inside the hole to give the filler something to bear against, then fill in layers rather than one thick pass. Thin layers shrink less and crack less than one deep one.
Let each layer skin over before adding the next, and finish with a slightly wider, thinner coat that feathers out onto the surrounding wall so there's no ridge to sand down later.
Fixing a larger hole with a plasterboard offcut and mesh tape
Anything from about a fist-sized hole upwards is better patched with plasterboard rather than filled solid, which would take an unreasonable number of layers and never quite hold. Cut the damaged area back to a neat square or rectangle with a plasterboard saw or utility knife, and cut an offcut piece slightly larger than the opening.
Fix a couple of timber or plasterboard cross-battens behind the opening, screwed to the surrounding intact board, to give the new piece something to sit against, then screw the patch to the battens flush with the surrounding wall. Self-adhesive mesh tape over the joint, followed by two or three thin coats of joint filler feathered wider each time, will hide the seam once sanded.
Drying time and sanding before you paint
Plasterboard filler usually firms up within a couple of hours but needs longer to dry through fully, especially in a thicker patch or a poorly ventilated room. Give it at least 24 hours before sanding, and longer for anything filled in several layers or done in a cold or damp room, which is common over an Estonian winter with the heating not yet on full.
Sand with a fine grit sanding sponge or paper, working in circles rather than one direction, and check the patch by running a flat hand over it rather than relying on your eyes alone under indoor lighting. Wipe away the dust with a slightly damp cloth before priming, since paint over dust never quite bonds properly.
Tools and materials you'll need
Most small repairs need only a handful of basic items, and a tub of filler and a filling knife will cover several dents around a flat. Larger patch jobs need a few more things, but nothing specialist or expensive.
- Ready-mixed plasterboard filler and a flexible filling knife (or two, different widths)
- Fine grit sanding sponge or sandpaper, plus a dust mask
- For larger holes: a plasterboard offcut, self-adhesive mesh tape, a plasterboard saw or sharp utility knife
- Timber or plasterboard battens and screws to back a patch
- A damp cloth for dust, and primer or diluted paint to seal the repair before the final coat
When it makes more sense to call someone in
A single dent or a small hole from a removed bracket is a reasonable weekend job for most people, and there's no shame in leaving it there if it goes well. Where it gets harder is several patches at once, a hole large enough to need cutting and backing properly, or a wall that needs to look flawless afterwards under gloss paint or strong light, where every ripple in the filler shows.
If you'd rather not deal with cutting plasterboard, taping joints, or matching an existing texture, our plasterboard work starts from 28 € per job, and we also offer painting and decorating from 12 € per job if you want the wall finished as well as patched, not just repaired.
Filler alone is fine for small dents, but any hole wider than a few centimetres needs a plasterboard offcut behind it, and either way, give it a full day to dry before sanding and painting.