The ability to repair holes in plasterboard walls depends a lot on the size of the hole in question. There are several methods for repairing holes, but not all are suitable for all sizes of hole. Here we will take a look at repairing small and medium holes (up to about 120mm wide) in plasterboard.
Repairing Small Holes in Plasterboard
Any holes smaller than about 15mm wide can quickly and cheaply be fixed using standard wall filler. Mix up your filler as per instructions and start to build up the edges of the hole with small blobs. Use the corner of a small Putty Knife or an old wide-bladed screwdriver.
When you have built up the edges of the hole as much as possible, but have not actually filled it, let the filler set for a while. Now go back and fill the remainder of the hole, leaving the filler slightly proud of the surrounding wall. When this is completely dry, sand it back flush with fine sandpaper on a block.
Repairing Medium-Sized Holes
Holes between 15mm and 120mm wide will need to be fitted with a backing piece of wood to stop the filler just falling through the hole. The first thing you need to do here is to draw a rectangle around the hole so that the broken section is just inside the lines. Drill holes inside each corner of the square and use a Padsaw to cut out the square.
Rather than a jagged hole, you now have a nice neat rectangular hole. Find an offcut of plywood or hardboard and cut a backing piece out of it. This needs to be the same width as your hole so that it will slip inside, but longer at each end so that it won’t pull back out. 25mm extra at each end should be fine.
Drill a small hole in the middle of the wood and thread a bit of string through it. Tie a nail to the string at the back of the wood so that the string will not pull out. The idea is to slide this backing piece into the hole, then pull it tightly against the back of the surrounding plasterboard using the string as a handle.
Before doing that, spread filler or coving adhesive over the 25mm sections at each end of the wood. Slide the wood through the hole and guide it into position until you can use the string to pull it against the back of the hole. Hold it for a while to allow the adhesive or filler to stick.
Once the adhesive has fully set, cut the string and let the nail fall behind the plasterboard. Start to fill the recess with quick-drying filler, but only fill it halfway. Let this layer dry and then fill the remainder of the hole until the filler is slightly proud of the surrounding surface. Skim off the excess filler with a straight edge and allow it to dry. You can then smooth off the filler and redecorate the area.