Fill

How to fill holes in a wall or ceiling

Small holes

Small holes are easy & simple to fill.

1. remove any loose material from the hole
2. if the hole is in plasterboard, best to cut off any unbonded little flaps of paper
3. Squish filler into the hole with a filling knife
4. Either wipe it with the knife or scraper to make it dead flat, or let it set proud and sand it level later.

Tips:

• If you're filling paper surfaced plasterboard, do the mimimum of sanding, if any.
• If the hole is open backed or deep, push something to the back of the hole first to block it, such as screwed up paper.
• If the sides of your hole are crumbly, even after removing loose stuff, brush them with diluted PVA before filling. (Many other glue types could also be used)
• Fillers often shrink slightly on setting, making deep layers crack. To deal with this, fill the hole to slightly below the final surface first, then fill full once its set.

Medium holes

Some holes are too big to support filler without it slumping or dropping out. These need something to support the filler, then are filled as for small holes. Any of the following can be used:

• any type of rigid board, eg plasterboard, hardboard, etc
• cardboard just about works
• metal mesh inside the hole

Use of lightweight filler increases the size of hole that can be filled unsupported.

Large holes

Large closed-backed holes can be filled with plaster, artex, sand & cement, sand & lime, filler or anything similar. Limit the depth of each layer, letting each set before applying the next. Max depth per layer depends on the filler used.

Large open backed holes require fitting with plasterboard before filling. Often a piece a little bigger than the hole is cut, inserted at 90 degrees and turned round to block the hole. Its then held in place before filling somehow, eg

• string and weight for ceilings
• tape, doesn't always work though
• bit of filler round the edges
• iron wire
• etc

Another way to use PB in the hole is to cut it to fit entirely within the hole, fit it in just very slightly recessed, using wedges of cardboard/wood/paper to hold it temporarily, and fill around the edges to stick it in place, pressing the filler in deep. Remove wedges when set and complete the filling.

Another option is to fit some wooden sticks behind the hole that will support the new plasterboard piece. The sticks are either glued to the existing plasterboard, screwed to the existing plasterboard, or for a much stronger result fixed to the existing woodwork behind the plaster. The new plasterboard can then be screwed to the wood.

Another way is to cut the hole back to expose 2 joist surfaces, and screw a new piece of PB to the joists. Its a good idea to also screw a strip of wood to the back of the pb, screwing the old pb to it each side of the hole.

Nailhead popping

Remove anything loose & fill, wiping it flat with a spatula. However these holes have a tendency to reappear due to slight movement of the plasterboard. If this happens, drill a very shallow recess for a screwhead using a countersink, and put in a plasterboard screw to hold the board firmly. Fill over both holes, and hopefully the problem won't recur.

On walls the screw hole should be above the ding, so it goes into an upright. Ceiling joists can run either way, ie parallel with any of the walls. An extra hole is easily filled though.

Fillers

See Filler for filler types

Not enough filler?

• Fill much of the depth of the hole with polystyrene etc first
• Poke gravel into the filler to use less

See also

• Filler
• Patching plasterboard demonstrates the wood support method