If you’ve kept up with our regular blogs over the years, you’ll know we almost exclusively talk about paint. It makes sense; the clue is in the name after all!
But in a lot of our painting guides and advice blogs, you’ll notice a particular product pop up a lot. That’s right, today we’re giving sandpaper some time in the spotlight.
The Importance of Sandpaper for Exterior Painting
In order to get the most out of your exterior paint, the surface you’re applying paint to needs to be as smooth as possible.
Let’s use outdoor wooden furniture as an example. The wood surface may be coarse, making it tricky to apply an even coat with a paint brush or paint roller. By sanding the surface first, painting it becomes a breeze, and any roller or brush will get the job done.
Arguably the most important step in any painting process is how you prepare the surface. And the most important part of prep is cleaning the material you plan to paint.
This is especially crucial for exterior painting, where dirt, grime, and dust can build up easily on surfaces that are exposed to the elements. Even a powerful jetwash might not be able to remove all dirt, in which case you need sandpaper to get rid of the stubborn stuff.
If the surface has been painted previously, it’s best to remove all the existing layers of paint before applying a new coat. This is because exterior paint, and especially primer, is designed for specific surfaces, and will cling to the exposed surface better than old paint. Even if the paint isn’t cracked or peeling, you can use sandpaper to just smooth it out, so it doesn’t show through your new layers.
Any imperfections will show through even multiple layers of new paint. It’s very important to clean and prepare the surface properly so you don’t waste time and money.
Which Interior Surfaces should be Sanded Before Painting?
Of course, sandpaper is just as useful inside your home. You can use sandpaper for the following interior surfaces:
- Walls
- Floors
- Ceilings
- Door & Window Frames
- Skirting Boards
- Metal Radiators
- Furniture
- Cupboard Doors
Nearly every surface in your home, literally floor to ceiling, can be prepared for painting using sandpaper. If you have metal surfaces with rust, wooden surfaces, peeling paint, even flecks of plaster on new walls; they can all benefit from sandpaper to help your paint look its best.
But which type of sandpaper should you use?
Types of Sandpaper
Sandpaper can have different grit levels that change what surface it suits best. This separates it into 3 categories:
Coarse – Coarse sandpaper has a grit level of 40-80. This is best for removing multiple layers of paint, or for sanding hard surfaces like stone or concrete.
Medium – Medium grit sandpaper has a grit level of 100 – 150. It’s ideal for dulling existing layers of paint, or for removing dried flecks and runoff. It is also good for sanding laminate.
Fine – Fine grit sandpaper has a grit level of 180 – 220+. If you just need to smooth an existing layer of paint, this is ideal. It can also be used after you’ve sanded with a high grit sandpaper to ensure the surface is even. Recommended for most interior projects.
Essentially, the rougher the surface, the lower the grit level you need. If you sand a surface with a coarse or medium sandpaper when fine would’ve been ideal, you risk damaging the surface. On the other hand, using a fine sandpaper will take longer.
Sandpaper can also be applied in a range of ways, which affects its performance.
How to use Sandpaper
The best Sandpaper can be used either by hand or with a tool. For smaller interior projects like furniture or skirting boards, doing it by hand doesn’t take very long, and is worth the effort.
Larger surfaces, such as floors or walls, need something more heavy duty. A palm or orbital sander guarantees a smooth surface, in less than half the time it would take to do it manually. For floors we recommend a professional belt or floor sander as doing it with anything less will drain a lot of your decorating time.
The choice isn’t just between hands or power tools. A sanding block or sanding sponge will make the task much simpler than using loose paper, which can tear or is simply awkward to use.
If you do commit to sanding by hand, there are a few techniques you can use to make it easier.
Tips for using Sandpaper
If you’re sanding wood, always sand with the grain, not against it.
Avoid over-sanding, this can damage the surface beneath and show through the new paint.
The type of paint you’re using will affect how thorough your sanding needs to be; gloss paint and other opaque paints can cover some imperfections.
You should still sand wood even if you are applying a stain or varnish.
Most packs of sandpaper will tell you what materials it works best with.
The UK’s Most Trusted Paint Supplier
Sandpaper is the unsung hero of the decorating world. Without it our painting projects would be much more difficult, and the results not something to be proud of. As most surfaces need to be sanded, learning the ins and outs of sandpaper, and the how to use it, will help you interior and exterior surfaces look fantastic.
We’re the no.1 choice for tradespeople, with large quantities of paint available at competitive prices, and we’re loved by domestic painters too! We also provide a wide range of painting accessories, including trusty sandpaper!
For more painting advice and guides, check out our blog. And if you have any questions about us or any of our products, please get in touch.
FAQ's
What grit sandpaper for gloss paint?
To remove gloss paint from a surface, we would recommend you start with a medium grit sandpaper with a grit level of 100. After this you should then use a fine grit sandpaper with the grit level of 180 to even the surface and create a flat base for the paint to adhere to.
What grit sandpaper for plaster?
You should use 120 grit sandpaper on plaster before painting it to make sure that the that the paint will adhere to the surface. If plaster is too shiny then the paint want adhere, however if you are removing old paint from plaster, you should use a lower grit sandpaper of 80 to remove the paint, then a 120 grit sandpaper to smoothen the surface for the best result.
What grit sandpaper for skirting boards?
If you are sanding down years of paint then we would recommend you use a lower grit sandpaper with a grit level of around 80. If you are just evening the surface then you can use a higher grit of around 150-180. The best practice is to start with a lower grit and to work up to a higher grit, to ensure the skirting board is as smooth as possible to adhere new paint.
What is the best sandpaper for metal?
To remove old paint from metal you should use a sandpaper with a grit level of 120, however if the paint on the metal is in good condition you should use a higher grit of around 200.
