Plaster is key when it comes to protecting and finishing your walls. When done correctly, plaster allows you to create the smooth surface needed for decorating your home. Applying plaster may sound simple enough and in many ways it is, but just like any skilled trade there are certain tools, preparation, and methods needed to ensure a professional looking finish.
When it comes to DIY plastering there are several reasons why projects may not go as planned, and more often than not, these can be avoided by steering clear of the following mistakes.
Common Mistakes when Plastering
1. Not Cleaning or Priming The Surface
Preparation is key when applying plaster to any surface. Poor preparation will cause plaster to not adhere to the surface properly, which can lead to issues in the future. If you’re going to apply plaster, you should first ensure the wall is clean and free of dust, dirt and debris.
Any loose material should be removed and any cracked or flaking plaster should be knocked off. If there are areas that aren’t coming off as easily, you can use sandpaper or a wire brush to remove it. As well as cleaning the surface you should also apply a PVA primer. PVA primes porous surfaces like brickwork or old plaster. By preventing water in the plaster from evaporating too quickly you’ll reduce the risk of cracking and improve adhesion.
2. Using The Wrong Mixture
Having the correct plaster mix will not only help when applying it but will also help your plaster to last longer. The perfect plaster mix requires roughly 11.5 to 12.5 liters of clean water for a 25kg bag. When mixing plaster you should always add the plaster to water to avoid any lumps, not vice versa.
The mixture should be thick but runny enough to spread smoothly. If you take the plaster onto your trowel and it drops straight off you need to dry it out. Add the plaster to water bit by bit if it’s too thick.
3. Using The Wrong Type Of Plastering Tool
Using sub-par tools when plastering will only cause you issues further down the line.
Using a large mixing bucket and mixer drill with a paddle attachment are best for mixing your plaster, and you want to mix your plaster until it’s as smooth as possible without any lumps. You can mix plaster by hand but it’s unlikely you’ll get as consistent of a texture as you would with a machine.
Keep all of your tools clean when plastering as any leftover old plaster on your tools can ruin your mix. It’s always best to have a measuring jug for each batch of plaster you mix. This will allow for more consistency between each mix.
4. Not Allowing Enough Drying Time
Don’t be tempted to apply another layer of plaster if you’re struggling to get an even finish. By adding more plaster before the original layer has dried you are at risk of causing blistering, cracking and weak finishes. The thicker the layer of plaster, the longer it will take to dry out. This is because there is more moisture in the plaster that needs to evaporate.
Always follow the manufacturers guidelines and be patient. By allowing enough time you know for sure each layer of plaster has dried properly and will bond correctly.
5. Not Respecting The Curing Process
Drying and curing plaster are two completely different things and by skipping curing times you’re doing more damage than good. During the curing process your plaster continues to harden, which can take anything from a few days to even weeks.
Think of curing as the plaster reaching its full strength.
6. Choosing The Wrong Sandpaper Technique
Sandpaper may seem like a minor detail when plastering, but it’s something that can make or break your finish. Always start with a medium grit sandpaper, and then move onto a finer grit for a smooth finish. Ideally, you want to start around 120 grit as it allows you to remove imperfections without damaging the plaster, and then move up to a 220 grit to really refine the finish.
Using the wrong sanding technique can leave obvious scratches on walls or even worse an uneven surface.
Conclusion
Plastering takes a lot of skill and experience, and it is not as easy as it looks. DIY can be very tempting but making one of these common mistakes can cause you more hassle and more money down the line.
That’s why at Corinium plastering we strive to provide you with top-quality plastering finishes. Get in touch with Corinium Plastering today for expert advice and a free quote.