Guide written by:
Anne, Painter, Cambridge
Varnish is a resin-based product used to form a protective transparent coating on wood. Applied using a paint brush, roller or paint gun, varnish covers wooden furniture and other items with a protective layer that helps them to withstand impacts, scratches, staining, weathering and even some kinds of bacteria. What's more, it retains the natural look of the wood and won't cover up the wood grain or any knots.
Furniture varnish can also be used beneath paint to give it a long-lasting shine and to stop the paint from flaking. This product also makes your wooden furniture easy to clean – you just need to wipe it down with a damp cloth!
There are various types of wood varnish to choose from. Make your decision based on the type of furniture or object you're hoping to cover, the look you want and type of application (i.e. indoors or outdoors).
Varnish for wooden furniture and other wood objects is made of resins (such as polyurethane, acrylic, cellulosic resins, etc.) which are dissolved in a liquid. Varnish is categorised according to the type of liquid used. There are three main families:
There are two further categories: natural varnish and marine varnish.
Solvent- or oil-based varnish is very hardwearing and gives surfaces a beautifully smooth effect which is even shinier if you choose a gloss varnish. Mostly used outdoors, this type of varnish is easy to sand down when it comes time to restore your wooden furniture.
However, this type of varnish releases a strong smell, can be tricky to apply and dries very slowly as you have to way for the solvents to evaporate. Oil-based varnish also tends to yellow over time and it is more tedious to clean your tools as you have to use white spirit.
This type of varnish, whether you go for an acrylic or polyurethane-based product, can be diluted and cleaned using water. More environmentally friendly and safer for your health than solvent-based varnishes, this product releases less odour and won't yellow with time. While it is relatively easy to apply, it dries quickly meaning you have to work fast.
Water-based wood varnish, or solvent-free varnish, is slightly less resistant and offers a less smooth finish than oil-based varnishes. Used mainly indoors, these varnishes are trickier to sand down and to add colour to if required.
These oil-based varnishes also contain water molecules. Odour-free, a hybrid varnish provides wood with a beautiful amber-toned finish, dries quickly and won't yellow. Suitable for indoor and outdoor use, these products are more difficult to apply than the other two types of varnish and are costlier.
These varnishes are made using natural preservatives and are more environmentally friendly and safer for your health while also being durable and resistant.
These varnishes will often be labelled 'non-toxic' or 'solvent-free', but the best option is to choose a low VOC or VOC-free product.
No matter whether you go for a water- or oil-based varnish, furniture varnishes come in three main finishes.
Matt varnish is subtle and allows the grain of the wood to show through while also minimising flaws.
Satin varnish, made to reflect a little light, leaves a slight film on the wood that looks quite similar to a wax finish. This is a popular option for light-toned wood furniture.
Glossy varnish draws attention the wood and gives it depth by reflecting the light. But be careful – this type of varnish will accentuate imperfections. Gloss varnish is mainly used to brighten up dark wood furniture.
Furniture varnish can be clear or coloured. A coloured varnish will add a hint of colour to the wood in addition to protecting it and, unlike paint, leave the grain of the wood visible. They come in a wide range of colours from white wash to oak and teak, as well as a range of tones including red, green or even black.
It's also possible to add colour to clear varnish yourself using powdered pigments or paint. But be sure to check that the products you use are compatible and bear in mind that results may alter once the varnish is dry.
Your choice of furniture varnish depends on how you want to use it:
Guide written by:
Anne, Painter, Cambridge, 59 guides
After 8 years of trade, I turned professional: I trained myself to be a painter and carpet fitter, either on my own or with 16 year old comrades. 9 months later, following vocational training, I created my company. I’m a self-taught DIYer and decoration enthusiast, I love to find and restore furniture and to create unique decoration pieces. I completed the renovation of my sister’s house with my niece: electrics, tiling, plasterboard...we did it all. And today, if I can share my experience I'm happy to do it. Good Luck.