Got a hole in your plaster wall that needs to be fixed? This simple guide will walk you through fixing big and small holes, as well as giving some quick advice on how to fix cracks in plaster.
The first thing you need to consider is, how big is the hole? Small holes in plaster are much simpler to repair than large holes. In the case of small holes, the damage can simply be filled in with some plaster cement. With larger holes, where there is nothing but air behind, you’ll need to create a backing out of wood or plaster and then plug the hole with a replacement piece of plaster. Keep reading for the full instructions.
Repairing small holes in plaster
You’ll require: Plaster cement, sandpaper and a plastic blade or filling knife.
1. Begin by preparing the area. Neatly cut away any loose plaster and use a vacuum cleaner or damp cloth to clean up plaster dust.
2. Mix your plaster cement using the packet instructions. Once you’ve reached the right consistency, use your filling knife to apply it straight to the hole. Once you’ve covered the hole, wipe with a damp sponge and then leave the plaster cement to dry (approx. 4 hours)
3. If necessary, repeat step 2 and apply a second layer of plaster cement.
4. Once the plaster cement is dry, use your sandpaper to sand the plaster to a smooth finish so that it is flush to the wall.
5. Repaint the repaired patch.
Repairing large holes in plaster
You’ll require: Plaster cement, sandpaper, a plastic blade or filling knife, plasterboard joining tape, plasterboard screws, adhesive, an offcut of plasterboard the same thickness as the plaster in your wall, more plasterboard or some wood to use as backing strips, a keyhole saw and a screwdriver or drill.
1. Begin by measuring up your piece of offcut plasterboard and cutting it to size. It will need to fully cover the damaged area.
2. Hold your replacement plasterboard up to the hole and trace around it with a pencil.
3. Before beginning cutting, ensure that there are no electric wires or cables behind the hole that you are likely to come into contact with. Once you’re ready to cut, begin by punching holes with a screwdriver into the plaster at each corner of your traced outline. Then, using the keyhole saw, cut diagonally towards the corners from the damaged hole and along your traced outline.
4. Carefully breakaway and clear the damaged pieces of plasterboard. You should be left with a clear, rectangular hole the same size as your replacement piece of plasterboard.
5. Next cut your backing strips to size. They should be around 100mm longer than the hole and 150mm in width. Position them so that they are behind the existing wall and screw them in place (countersunk). These will act as a backing to which your replacement piece of plasterboard will be adhered. (If you are using plasterboard as your backing strips you may wish to use adhesive rather than screws. This is quite acceptable, just ensure that you allow enough time for the glue to thoroughly set before moving onto the next step).
6. Use a damp sponge or vacuum cleaner to clean up any plaster dust.
7. Apply glue directly to your backing strips and position the replacement plasterboard so that it fits snugly in the gap. Using your joining tape, secure it in place – just ensure that you don’t overlap the ends of the tape.
8. Next you need to mix your plaster cement. Use your filling knife to apply it directly to the joints and carefully smooth it over the tape and screwholes.
9. Leave to dry and then carefully sand flush, being careful not to tear the tape or plaster board. You may wish to repeat steps 8 and 9 a few times, just ensure that you leave enough time for the plaster cement to dry between layers. Multiple, thin layers of plaster cement will create a smoother finish at the end.
10. Once you’re happy that you’ve created a smooth finish with no imperfections (run your palm across to make sure), repaint the repaired area.
Repairing cracks in plaster walls
There are a few different methods suggested for repairing cracks in plaster walls. Cracks normally occur because the house is naturally contracting and decontracting with changes in temperature – typically following the seasons. However because of this, sometimes just filling in the cracks with plaster cement, as you would for a small hole, doesn’t make for a long term solution.
A professional plasterer will be able to recommend the best long-term solution for your home, however if you’d like to have an attempt yourself, the following techniques could work.One is to fill the gap with a latex caulk rather than plaster cement. The idea is that the latex would expand and contract with your house, thereby helping to prevent the reappearance of cracks. Alternatively, applying joining tape over the cracks before repairing as for small holes in plaster can also be an effective method. The joining tape helps to prevent future cracks by allowing a small amount of movement.
While the steps above are pretty straight forward, remember if you’re unsure at all or don’t have the correct equipment, go ahead and post a plastering job with Service Central. It’s free and you’ll have a qualified, local handyman or plasterer contacting you about your job in no time at all.