Small hole: Small holes and cracks in wood can be filled with ready-mixed filler. Clean out any loose dust and debris from the hole, dampen the area to avoid shrinkage, and put the filler into the crack or hole using a wide filling knife. Smooth it over and allow to dry for one to two hours. When the filler is dry, rub it smooth with fine-grade sandpaper.
Larger hole: For a larger hole in a solid wall that is more than 2.5cm deep or wide, it is better to apply a base layer of filler. Let it dry, then apply a second layer, finishing as described.
Repairing a Hole in Plasterboard
To fill a hole in a plasterboard wall, that measures less than 5cm (2in) wide, start by applying meshed jointing tape over the hole so you can start your plaster repair. Spread filler over the tape (some will squeeze through the mesh), then use a wide filling knife or a caulking tool to smooth it level. When dry, rub smooth with sandpaper. For larger holes up to 20cm wide.
Measure the hole and cut a piece of plasterboard lath, slightly larger than the hole. Attach a length of string to the lath by drilling a small hole, threading the string through, and securing it at the back. Dampen the edges of the hole and the lath and apply dabs of filler around and behind the hole and on the corners of the lath.
Carefully place the lath into the hole, and, using the string to pull the lath into place, position it to cover the hole with the dabs of filler against the back of the plasterboard. Hold the lath in place by the string tie, for a few minutes, while the filler sets enough to hold firm until it dries completely.
Spread a thin base coat of filler over the lath, making sure it is not as deep as the hole. Roughen the surface with the edge of the filling knife and leave to set. When the base is dry, remove the string with clippers and apply a finishing layer, skimming carefully to make it flush with the wall. Lightly sand before painting.
