Plastering

While the internet is very useful for many things, there are some limits to its power. It can’t plaster your walls. And neither can it really show you how to do it. But I believe with a little effort, lots of enthusiasm and my handy tips below, you can learn how to plaster a room on your own.

The biggest stumbling block for most people is the initial application of the plaster to the wall. You will struggle to get used to using a trowel and a hawk first time round but please persevere. They are the tools the professionals use, so don’t decide there is a better way just because it seems easier to start with. By the time you have dropped half the mix on the floor you should be getting the hang of it. It is just a case of picking the mix up from the hawk and spreading onto the wall with the plasterers’ trowel.

The Basics

There are many forms of plastering but the popular modern technique involves the application of a thin coat of plaster to a background to produce a hard wearing smooth surface ready for decoration.

The plaster

The professionals choice is British Gypsum Multi-Finish Plaster (“a bag of finish please mate?”). Available at good DIY stores and all builders merchants in 25kg bags. It costs a little under £4 so don’t worry about buying too much. One bag will cover 6-8m ².

Mixing

To mix one complete bag requires approximately a full 3 gallon bucket (standard builders size) of water. This means you need a bucket twice as big to mix it in. Unless you have a desire for pain a paddle mixer in the end of a power drill is essential.

Pour the water gauged in the 3 gallon bucket into the mixing tub. Then gradually pour the plaster into the water while operating the mixer. Consistency is a matter of debate. A mix stiff enough to hang onto the trowel for a few seconds before falling is about right. Too stiff means hard work and too runny means a messy floor. Experience is the only answer to achieving the right mix every time.

Slap it on!

There are three stages to plastering and they can best be described as follows:

1. Once mixed the plaster is drying at its own pace and cannot be stopped so get it on the wall. Pronto. Apply to a 2-3mm thickness (but don’t bother getting the tape measure out) moving across the wall. Don’t worry about smoothing at this stage.

2. Having covered the entire wall move back to the beginning and begin to smooth out trowel marks, high spots and fill bits that have been missed. This is also a good time to tidy the edges. Follow the plasterers maxim: “Keep the edges clean and tidy and the middle will take care of itself” Once the plaster firms up a sponge and a brush can be used with the trowel. If the sponge drags the plaster it is too early. Wait ten minutes and try again.

3. As the plaster dries out it will firm up. This will enable a smooth surface to be achieved. Move across the wall with the trowel again. Keep the trowel lubricated with water to stop it dragging the surface. The aim is to remove any remaining trowel marks, and achieve a perfectly flat polished surface.

Once the plaster has been mixed it will begin to set in two to three hours. The setting cannot be delayed or speeded up by your intervention. Once the pink gypsum colour has turned to a darker shade you can do no more to it. Any further trowelling, sponging or wetting will only worsen the finish. Remember, there is always sandpaper!

Decoration

Even the best plaster needs a light rub down. And even the worst can look okay with a sanding and filling. Once the plaster has dried out fully (it should be a pale pink within 2 or 3 days) it is time for sanding. This is essential to remove the inevitable last few trowel or water marks. Never think your plastering will be so good you won’t need the sandpaper. Once sanded, I would recommend one coat of watered down white emulsion to seal the plaster. You will be amazed by how good it looks. Don’t get the filler out before you paint because the emulsion can hide a multitude of sins. Any dents or marks can now be filled and you are ready for decoration.