Tools and Materials you'll need:

• Tin can lid
• Wire
• Timber off-cut
• Wooden dowel
• Suitable filler
• Wallboard scrap
• Countersunk screws
• Sandpaper
• Primer & paint
• Wallboard adhesive
• Hammer and nail or punch
• Panel saw
• Keyhole saw
• Tin snips
• Trowel
• Putty knife
• Awl

Occasionally a plaster or wallboard finish is damaged when someone accidentally pushes a doorknob into it or knocks a hole in it with a sharp object. With a few simple tools and a little know-how the damage can be repaired, preferably soon after the accident before the damage can be made worse.

Small chips and cracks can be smoothed over with a suitable filling compound. Holes, however, will need some sort of backing to support the filling while it sets. One-way to provide a backing is by using a discarded metal lid from a can. It should be larger than the hole.

Punch two holes in the lid and loop a wire through the holes leaving a few centimetres of wire sticking out from one side.

Clean away any lose material around the hole. Measure the diameter of the lid and cut a slit extending out from the hole on each side so the lid can be slipped through sideways.

Holding onto the ends of the wire, push the lid through the slit. Once it is behind the wall, pull on the wire until the lid sits upright against the hole. Cut a chink of square dowel a couple of centimetres larger than hole and twist the wire around this to hold it in place.) Leave a chunk of wire sticking out from wall and spackle over the hole with suitable filler. Cover the tin lid, the edges and slit but don't worry about smoothing out the centre of the patch yet. Allow the first patch to dry then snip the wire off flush with the patch using tin snips.

Now apply a finishing coat of filler to bring the surface up level with the rest of the wall. Cover the remaining tip of wire and feather the edges of the filler out beyond the patch. Let the patch dry overnight before sanding smooth and priming ready for painting.

Larger holes.
To fill a large hole you will need an off-cut of matching wallboard slightly larger than the hole.

Place the off-cut over the hole and trace around it. Cut out around the traced line with a keyhole saw. Next, cut a strip of timber about 150mm wider than the widest part of the hole. Drill pilot holes about half-way down each side near the edge of the hole. Insert the timber strip and hold it in place so the pilot holes line up with the timber. Bracing the timber with one hand, push an awl through one pilot hole into the timber. Switch hands and push the awl through the other pilot hole into the timber.

Have a helper hold the timber in place while you insert countersunk screws into the pilot holes in wallboard and timber. Keep turning the screws until the flat heads are below the wallboard surface. Now spread some glue on the face of the timber and spread speckling compound on all four edges of the wallboard patch. Ease the patch into place and hold it until the compound starts to set. When the compound is dry, use filler to cover the slits around the patch. Finally, cover the whole patch and screw heads at each side with filler, trowel ling it smooth to match the rest of the wall. Allow the patch to set overnight before priming and painting.