Plastering | How to Plaster a Wall
Is it difficult to plaster a wall?
Plastering is a job that many people usually leave to the experts. However, if you prepare well and carefully using a practiced method, you can plaster a wall. The finished result is a nice smooth wall ready to pick up paint or wallpaper.
What do I need to plaster a wall?
Plastering a wall can take some time. Therefore, it is important to choose high quality tools that are comfortable to hold. A full list of the tools required can be found at the top of this page. However, the five basic tools are:
- Cleaning Trowel – Choose a stainless steel trowel with a comfortable, evenly weighted handle.
- A plasterer’s hawk board – this is the tool you can use to hold your plaster of paris. A plastic hawk board is lighter than a wooden board, although both types are perfectly fine. However, a wooden hawk board will last much longer.
- Bucket Trowel – This tool is specially designed to make it easy to shovel plaster from the bucket onto your hawk board.
- A power mixer – while it’s okay to mix the plaster by hand, using a power mixer is a lot easier and faster. It is especially useful when creating large amounts of plaster that need to be applied quickly.
- A good quality brush – this is important for keeping your edges clean and for applying water to your plaster.
If you re-use tools for plastering, make sure they are spotlessly clean with no plaster residue from a previous job.
Prepare the wall for plastering
Plastering can be very messy, so a clear, unobstructed work area is vital. Make sure to remove all furniture from the room. Depending on the job, you may also need to remove curtain rails, dado rails, and even radiators. Tape up all sockets to prevent plaster from getting into them.
- Put heavy-duty protective films on the floor. When removing old plaster you will need two sets of sheets – one to remove the old plaster and one to apply the new plaster. Otherwise there is a risk of dust contaminating your new plaster.
- Thoroughly clean and scrub the wall, removing wallpaper, loose plaster, grease, and dust. This is very important as any residue left on the wall will prevent the plaster from adhering properly.
- If you are working with a new plasterboard, apply plaster tape to cover any joints between the plasterboard. Once the tape is in place, use a sharp knife to cut the tape to a clean edge.
The next step is to apply PVA glue, which is essential for holding the plaster to the wall. The PVA must be diluted before application. It is therefore essential to follow the manufacturer’s instructions. A ratio of 1 part glue to 4 parts water is common. Roll or brush the glue onto the wall. Don’t wait for the glue to dry completely. Once it feels a little sticky (or “sticky”), you can start applying plaster of paris.
How do I mix the plaster?
Always follow the manufacturer’s instructions when mixing plaster of paris. To avoid contamination, use a clean bucket, fill it with clean tap water, and add the plaster steadily. This will help you avoid getting a lumpy, uneven mix.
Use a bucket ladle to apply dry plaster to the edge of the bucket.
You can either mix the plaster manually or use an electric mixer. A power mixer is better suited for larger jobs if you apply a lot of plaster in a short period of time. Use the power mixer at a slow speed so you don’t overwork the mixture. Keep stirring until the mixture is smooth, lump-free, and has what has been called a “thick pudding” consistency.
When you’re done mixing the plaster, clean the power stirrer before the plaster sets on the blades.
How do I apply the patch?
If you want to plaster a large area, it is best to pour your plaster onto a spotboard. The mixture should spread, but not run over the board. Use a bucket ladle to cut off some of the plaster and transfer it to your hawk board. Use a small amount to start with if you are not used to handling the hawk.
To apply the plaster to the wall, do the following:
- Use the plaster trowel to pick up a small amount of plaster from the hawk board. To apply the plaster to the wall, spread the plaster firmly with an upward stroke with the trowel angled slightly away from the wall.
- At the end of each stroke, smooth the trowel to smooth the plaster.
- Work up and out from the lower left corner of the wall, using a small amount of plaster each time.
- You can use short sweeps first, then longer sweeps to smooth them out.
- Continue working your way along the wall until the plaster is evenly distributed over the entire surface.
Make sure to disconnect the power when plastering around a lamp socket and protect the socket with tape.
Let the first layer of plaster dry slightly for about 20 minutes. You can then go over the plaster again with a trowel to level out any unevenness. If necessary, spray some water on parts of the plaster. This means that the plaster reacts better to the trowel. Remember to smooth the corners and edges with a damp brush to even out them.
Apply a second layer of plaster of paris and repeat the steps above. The main difference from the second coat is that it has to be a much smoother and more even finish. For the second layer, the plaster needs to be a little thinner – see the manufacturer’s instructions for the best results.
Allow the plaster to dry slightly according to the manufacturer’s instructions. The surface should still be slightly damp but firm enough that it doesn’t move when you touch it.
How do I finish plastering?
Once the plaster has dried to the right condition, you need to buff your work off. Go lightly over the surface with a clean trowel blade, moistening the surface with a spray bottle. Tilt the blade again slightly so that the edge smooths over the plaster.
Use a small damp brush to buff the edges and corners.
As soon as the plaster is completely dry, it can be painted or wallpapered. Remember to seal all bags of unused plaster of paris. Note, however, that the plaster of paris mixture will only last a few weeks.