How to fill holes in plaster
Updated: October 2026
You have a small hole in indoor plaster, the wall around it is dry, and you are about to push in one thick plug. That plug skins over, sinks as it dries, and then gets sanded while the middle is still soft. The repair looks flat for a day and cracks at the rim after the first coat of emulsion. This page is the sequence for a hole you can already trust: loose crumbs out, filler in layers no thicker than the pack allows, then a wait before you sand. It is not a ranking. Pack depths come from the amazon.co.uk listings in our [indoor plaster comparison](/hub/paints-and-varnishes/plaster-indoor), checked on 21 October 2026. We did not time a cure in a lab. A qualifying purchase can earn a commission at no extra cost to you.
You have a small hole in indoor plaster, the wall around it is dry, and you are about to push in one thick plug. That plug skins over, sinks as it dries, and then gets sanded while the middle is still soft.
You have a small hole in indoor plaster, the wall around it is dry, and you are about to push in one thick plug. That plug skins over, sinks as it dries, and then gets sanded while the middle is still soft. The repair looks flat for a day and cracks at the rim after the first coat of emulsion. This page is the sequence for a hole you can already trust: loose crumbs out, filler in layers no thicker than the pack allows, then a wait before you sand. It is not a ranking. Pack depths come from the amazon.co.uk listings in our indoor plaster comparison, checked on 21 October 2026. We did not time a cure in a lab. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Depth claim | Dry or set claim | Form | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Palace Palace fine surface filler 600 g | Layers max 3 mm | n/a | Ready mixed | 9.2 | about £1.25 | View offer |
| Best value |  Palace Palace interior patching plaster 1.5 kg | n/a | Fast set; mix 1:2.5 | Powder | 9.0 | about £2.49 | View offer |
| Alternative |  Sika SikaWall all purpose filler 600 g | 9 mm by 25 mm wide | Quick-drying | Ready mixed | 8.8 | about £4.49 | View offer |
Holes this method is for
The hole this method will touch is small, dry, and still attached. A screw hole, a rawlplug hole, a chip where a door handle knocked the skim, or a modest hole after a curtain bracket came off, with solid plaster at the edge, is in scope. A tap nearby should sound like plaster, not a drum. A hollow ceiling, a damp stain, a sag, or anything that moves when you press the edge is out of scope. If you have not chosen a pack, use the buying guide.
Palace fine surface filler is for layers no more than 3 mm. SikaWall's listing allows up to 9 mm deep and 25 mm wide, and the sheet says not to rework a greater depth in one pass. The Polyfilla kit bullets stop at holes up to 10 mm. A hole you can put two fingers through is already a patch. Scrape the hole out before you decide. What falls out tells you whether you are filling a clean void or chasing loose skim.
Prepare the hole
Take out anything that is already loose. A wallpaper scraper or the back of a filling knife is enough for crumbs, flaking paint, and the soft rim of an old fill that failed. B&Q's how-to says to scrape, widen the hole slightly so the filler has a shoulder, and vacuum the dust. Polycell's how-to starts from a dry surface. If the hole still sheds powder when you touch it, the filler is going to sit on dust. Vacuum or brush. Do not soak the plaster. Trade guides often say to dampen the edges of old plaster so it does not suck the water out of a gypsum mix. That step is not printed on these amazon.co.uk listings. If you dampen, the surface still has to be dry to the touch before paint.
Nail heads and screw heads need a coat of oil-based paint before filler, which is Polycell's instruction, because a bare steel head flashes rust through emulsion. If the fixing is gone, you are filling the hole, not painting the metal.
Fill in layers
Press the filler in rather than spreading a proud slab. Polycell's how-to says to press the filler into the hole and draw a wet knife over it. B&Q says to leave the fill slightly proud so you can sand it back flush. Proud is a fraction, not a lump. On Palace fine surface filler, keep each layer to no more than 3 mm and let it dry before the next. On SikaWall, stay inside 9 mm deep and 25 mm wide, and the sheet allows about an hour between layers. On the Polyfilla kit, the bullets say holes up to 10 mm. Do not treat that as permission for a 20 mm plug.
A rawlplug hole about 8 mm deep and 6 mm across is two or three layers of the fine filler, not one. With SikaWall you are inside the printed depth, and you still shape it before it cures, because UK reviews of that tub say the set goes hard to sand. With Palace patching plaster you mix a teaspoon, not the box. Reviews say a batch was unusable after about 5 to 10 minutes. Throw away a mix that has gone off rather than adding water.
Sand, dust and paint
There is no single drying time for every tub in this set. The Polyfilla kit bullets say surface dry in 1 to 2 hours and recoatable in 2 hours. Soudal's listing says paintable in as little as 15 minutes, and one of the two UK reviews says the time depends on thickness. SikaWall leaves about an hour between layers if you had to go deeper than one pass. If the pack does not state a time, wait until the fill is the same colour through and firm under a thumbnail. Sanding a skin traps soft filler underneath.
Sand flush, not through the surrounding skim. The Health and Safety Executive's page on sanding taped plasterboard joints puts avoiding the dust, or on-tool extraction, ahead of a mask. Ventilate, sand lightly, and wipe the dust off before paint. If the mark is a line that came back, use the crack guide. If the wall still drums, stains, or opens again, stop. More filler will not fix that.
Common questions
Do I dampen the hole?
Not because these listings say so. Polycell and B&Q start from a dry, clean surface. Some trade guides dampen the edges of absorbent plaster before a gypsum patch so the background does not steal the mix water. That sentence is not on the Palace, SikaWall, Soudal, or Polyfilla listings in this file. If you dampen, keep it light, and do not fill a wet hole. A damp stain is a leak, not a mixing tip.
How thick is one layer?
Use the pack you bought. Palace fine surface filler says no more than 3 mm a layer. SikaWall's listing allows 9 mm deep and 25 mm wide, and the sheet says not to rebuild past 9 mm in one pass. The Polyfilla kit bullets say holes up to 10 mm. Polycell's how-to adds layers above 10 mm for its multi-purpose filler. A thicker single plug skins, sinks, and cracks at the rim.
Should nail heads be painted first?
Yes, if the metal is staying in the wall. Polycell's how-to says to coat nail and screw heads with oil-based paint so rust does not come through the filler and the emulsion. Let that paint dry, then fill around it. If you have already removed the fixing, you are filling an empty hole and there is no head to paint. Do not leave a ring of wet oil paint on the plaster.
When can I sand?
When the pack says the fill is dry, not when the surface looks dull. On the Polyfilla kit that is surface dry in 1 to 2 hours, and you still recoat on its 2 hour line only if the fill is actually firm. A deep layer of another product can skin while the core is soft. If a thumbnail dents it, wait. Sanding early rolls the filler out and scratches the skim around the hole.
When can I paint?
After the fill is dry to the pack's own line and the dust is off. Soudal's bullets say as little as 15 minutes, and a UK review says thickness changes that. The Polyfilla kit says recoatable in 2 hours. SikaWall wants about an hour between layers if you built it up, then a full dry before decoration. There is no shared clock. Emulsion on a soft fill sinks and shows the hole again.
What if I mixed too much powder?
Throw the surplus away once it starts to stiffen. Palace patching plaster reviews describe about 5 to 10 minutes before a batch is unusable, which is shorter than sets within 2 hours on the shop page. Adding water to a setting mix makes a weak, lumpy fill. Next time mix a tablespoon at a time for a single hole. Leftover dry powder in a sealed bag is a different question from a wet mix you cannot save.
Is a dust mask enough?
A mask is not the first control the Health and Safety Executive describes for sanding gypsum at work. That page puts avoiding the dust, or on-tool extraction, ahead of respiratory protection. For one hole, sand as little as you can, keep a window open, and wipe rather than power-sanding a wide area. If the coating might be old textured paint, stop and get it checked rather than sanding it. This page does not describe asbestos removal.
Related pages
Sources
Public sources from the research digest, last checked on 22 October 2026. Shelf prices and star lines are the amazon.co.uk figures stored on 21 October 2026. The price band is this set, not a market average. No listing was lab-tested.
- BS EN 13279-1:2008, NBS (retrieved 21 October 2026)
- HSE: sanding plasterboard joints (retrieved 21 October 2026)
- HSE CIS36: construction dust (retrieved 21 October 2026)
- British Gypsum White Book, finishes (retrieved 21 October 2026)
- Palace Chemicals, patching plaster (retrieved 21 October 2026)
- Polycell: fill holes and cracks in walls (retrieved 21 October 2026)
- SikaWall all purpose ready mixed filler data sheet (retrieved 21 October 2026)
- Wickes: Thistle Multi Finish 25 kg (retrieved 21 October 2026)