You’re most likely here because you want to have a go at plastering your wall yourself, rather than calling in a professional.
Well, we would all agree that plastering and rendering are highly skilled jobs and most folks feel out of their depth when it comes to handling such projects themselves. Still, if you are the dextrous type, have a steady hand, patience and a knack for working in a systematic and slow manner, then read on our guide on how to plaster a wall the right way.
This post will help you if:
you’re about to renovate a room and the walls could do with being replastered;
you’re motivated to acquire new handy skills and intend to plaster your garage to practise;
you’ve watched a few how-to videos on the topic but you still want to check out the process in more detail;
you wonder how to fix a damaged wall by patching it with plaster.
Right then, before we get to the step-by-step plastering process, let’s see what tools you need and learn what the wall preparation job involves.
The tools you will need
Mixing buckets – to mix the plastering material and PVA adhesive;
Water buckets – to clean your tools and dip in a paintbrush when needed;
Stiff-bristled brush – to clean the wall from dust and debris;
Paint roller – to apply the PVA primer;
Paintbrush – to keep wall surfaces or the trowel wet during the process;
Mixer – to mix the plaster;
Stepladder – to reach high spots;
Bucket trowel – to scoop plaster from the bucket to put on the hawk;
Hawk – to transfer the plaster onto the trowel;
Trowel – to spread and smooth out the plaster on the wall;
Jointing/taping knife – to apply fillers in cracks and holes during the wall preparation;
Coarse- and fine-grit sandpaper – to sand over imperfections;
Masking tape – to protect wood trim work and light switches;
And let’s not forget some safety equipment
Protective gloves for trimming plaster;
Vinyl gloves for handling plaster;
How to prepare your wall before plastering
Most home improvement jobs need preparation, so this one is not an exception, too. Depending on whether the walls show signs of damage, suffer from cracks or you are confronted with sagging, blistering, bulging, flaking or loose old plaster, along with the paint on top, this may take you even a day or two. Patience is the key, here. So, don’t despair but inspect the surface to determine what type of preparation steps you need to take.
Protect the surrounding area
But first things first. As plaster is pretty messy to clean up, especially when it dries out, cover the floor with a drop-cloth, which you can secure by taping it to the trim work or the skirting board. The protective sheet will also absorb any builders dust that will be produced during the wall preparation and plastering process.
Before you proceed further, make sure that you have all your tools ready and cleaned. It’s very easy to mess up a plastering job if you use trowels and floats that are covered with remnants of old plaster. Keep a bucket full of water handy so that you can dip in tools when you’re finished with them.
How to patch plaster
How do you fix cracks in plaster?
Remove any loose plaster pieces from the damaged area.
Wipe the area clean with a damp rag to remove any dust particles or debris. The crack must be clean before repair.
Dampen the area around the crack. This will make the repair compound stick much easier.
Mix plaster or a jointing compound in a bucket and pour the material into a mud pan.
Apply the material to the damaged area using a plastering knife. In most cases, you will only need to add one layer of this material.
Make sure to even out any bumps after you’ve applied the material. The repaired area must be as flat as the rest of the wall.
Wait for 24 hours for the new compound to set.
Sand the repaired area, so it becomes smooth to the touch. You can do that with a fine-grit sandpaper.
Wipe with a damp cloth to remove dust from the sanding.
How do you repair a hole in a plaster wall?
Carefully chip away the damaged plaster pieces with a hammer and chisel. Try not to chip away too much material or make the hole bigger.
Smooth out the hole edges with a utility knife.
Apply a thin layer of bonding agent around the hole.
Prepare a new batch of plaster and apply the first coat.
Slightly scratch the first coat as it sets in. The point is for it to become slightly rough, so the second coat would set in more successfully when applied,
Wait for 24 hours for the first coat to dry out,
Apply a second coat of plaster.
Wait another 24 hours.
Sand the second coat of plaster with a fine-grit sandpaper until the line between the old and new plaster is no longer noticeable.
Remove old flaking or blistering plaster
Always investigate the reasons behind blistering and flaking plaster, first, as moisture issues and damp spots will remain if you just go over the problem areas and replaster them. Strip down carefully loose flakes of plaster and sand over the entire wall before approaching the step of applying new plaster.
How to fix sagging plaster
Sagging plaster is somewhat a rare wall damage issue in the UK, these days since lath and plaster surfaces have been long renovated across old British homes and business establishments with the use of plasterboards. Lathen plaster was last used in the 30s in the country. Still, if your property walls or ceilings have not been plasterboarded and suffer from sagging plaster problems, it’s best to address the issue by removing the entire old plaster and then just board up the lath. Alternatively, call in a professional who is familiar and experienced with fixing old-style plaster walls.
Clean up the wall surface
In both cases, after fixing any wall damage or when you want to prepare the wall before you plaster it, clean the surfaces with a stiff brush, sand over imperfections and wipe all the dust and debris with a wet cloth or a sponge. You can also use masking tape along the skirting board to protect the latter from plaster splashes.
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How to plaster a wall
Now then, let’s get down to business and find out how to plaster a wall in several steps. The guide below is suitable for plastering straight over a plasterboard or a plaster wall that has been cleaned, fixed and prepared for replastering.
If you’re dealing with plasterboards, apply plaster tape to cover the joints between the individual plaster sheets.
Once in place, trip the tape with your utility knife to make a neat edge.
Mix a PVA adhesive with water at a ratio of 1:1, or 1:2 and apply it with a paint roller on your fresh-prepared, clean wall that is now free of cracks and other types of damage.
Mix your plastering material in a bucket according to the product’s instructions. It’s important always to add the water first as this will keep the mixture from becoming lumpy. Ensure that the mixture is of the right consistency – not too runny and not too thick.
Note that the PVA primer should be semi-wet so that the plaster sticks and bonds with the surface.
Scoop some plaster with the bucket trowel and place the blob onto the hawk.
Transfer the plaster from the hawk onto the trowel.
Apply the plaster with the trowel on the wall and spread it over with upwards, downwards and sideways motions, in straight lines. If you’re working with plasterboards, start by applying a thin coat over the joints, then continuing from there to the rest of the wall.
Continue to use sweeping motions when spreading and smoothing out the plaster with your tool.
Try to work quickly, but not sloppily. This so you’d manage to cover the entire surface before the plaster begins to set.
You will notice that the first coat is not as smooth as you would like to, so wait a couple of minutes before you wet the trowel and go over any slightly protruding lines.
Try to get a feel of the surface and apply pressure with the trowel when smoothing out the imperfections by holding the tool straight. Be careful not to dig into the still wet layer of plaster as this will have the opposite effect, and you’ll have to start all over again.
Apply a second coat while the first one is still sticky and feels tacky to the touch.
Repeat the smoothing-out process by wetting the trowel with the paintbrush and getting rid of any lines.
The final touches to get that glass-like finish are done again with the trowel but this time, keep it dry. It will take between 2 and five days for the plaster to set fully.
Of course, every professional plasterer has their own little tricks and special techniques, whether they sand down the second coat with fine-grit sandpaper or use a float, mid-process, to smooth out the wall finish. Still, the above steps will get you through the task alright, especially if you’ve never done the job before yourself.
What’s the difference between plastering and rendering
Plastering and rendering are very similar as both processes are designed to apply a new finish onto a wall surface. Rendering, however, is used for exterior walls, where the materials used are designed for outdoor application. Often, rendering produces a finish that is not as smooth as the one you would get on your interior walls.
What about skimming
Skimming refers to a type of plastering technique, which is applied to refresh an already plastered wall that has no signs of damage and is free of significant imperfections. What you do is mix the plaster in the right water-to-powder proportion and cover the surface in one thin coat. Then, you skim the wall over with the trowel to refresh the old work and smooth out over the existing plaster. This is done so that a follow-up painting/redecorating job renders better quality results. Again, there are various wall skimming methods, of course.
Always keep your tools clean during the wall preparation and plastering process, as well as when you are done with the job.
When you tip the plaster from the hawk onto the trowel, get the knack of doing it fast to avoid dropping plaster on the floor.
The plaster should be on the outer edge of the trowel when going downwards over the wall surface and the other way round when you’re moving upwards.
Badly damaged plaster over lath is best addressed by plasterboarding the wall, first.
If you have any plastering tips of your own, why not share them with our readers in the comments below? Also, feel free to share this post with friends and family if you think that they will find it helpful and informative!