4 Types of wood finishes. What to use when and how? A clear guide

To this day, wood remains the most popular material for both interior and exterior joinery.
The biggest reason that wood still beats aluminum and PVC in, for example, windows and doors, are that wood is warm and has a natural look.

However, if you want to keep the wood with which you have built your project beautiful and in good condition, you have to protect it properly.

But the question is, with what?
What are the differences in wood finishes?
How do you know you’re using the right finish for the type of project you’re working on?

You will be able to discover all this briefly and concisely in this article!

By the time you’ve read this article, you’ll know everything about the 4 most important wood finishers.
Thanks to this article, you’ll never make mistakes in choosing the right product again.

Disclosure: At zero cost to you, I may get commissions for purchases made through links in this post. I earn from qualifying purchases as an Amazon associate. Products featured are selected based on quality, performance, and reputation, regardless of affiliate relationships.

Why is wood finishing important?

Wood was once a living material that contained a lot of moisture.
To make wood usable for building things, a period of drying time has passed to remove that moisture from the wood.
That will make the wood more dimensionally stable, but also smaller due to shrinkage.

To find helpful tips about how to dry wood properly, I recommend you to check out my article 4 correct ways to dry lumber.

However, after drying, wood remains very sensitive to water.
If you expose that dried wood to water again, it will swell and possibly warp.

That is why applying a moisture-resistant topcoat is so important. Applying wood finishers seals the porous wood so that moisture, dirt, and mold cannot penetrate, allowing the wood to maintain its shape.

But that’s not all, as the years go by, the wood will look different due to UV and weather conditions, for example.
The right finish ensures that the surface always looks beautiful and not dull and rough.

By using wood finishers, your wood always is well protected.
That way you can enjoy it longer, but also save time, money, and aggravation by not having to replace it.

How do you prepare a wooden surface for finishing?

Whatever type of wood finisher you use from the article below, you have to keep a few things in mind.
Always make sure that you have sanded the untreated wood, and remove all dust and dirt.
You can do this with a damp cloth or blow it away with compressed air.

Are there some small irregularities in your wood, and do you want to remove them? 
Then it is best to fill it beforehand with a wood filler.
Only after finishing this wood filler can you apply the stain protection layer.

You can treat new or untreated wood with a wood preservative before applying an oil, stain, varnish, or lacquer layer.
These products ensure that the wood will be deeply protected against weather influences, insects, and/or fungi.

However, if your wood has already been affected by fungi or woodworm, make sure to treat it with a specific wood treatment agent.
With these products, you will fight the infestations efficiently before applying wood finishes.

4 Types of wood finishes

Wood finish #1 – Oil

Natural oils are present in the wood.
After a while, the natural oil will disappear from your wood.
The place the oil occupied in the wood can now be occupied by water.
To make sure this doesn’t happen, protect the wood with oil, so the wood will be saturated.

Oils suitable for wood protection consist of very minute particles.
These particles penetrate deep into the wood and replace or supplement the original oil.
Oils to protect wood are, usually, based on linseed oil. (more in-depth info on linseed oil in my article, Raw Vs Boiled Linseed Oil. A Clear Explanation)

What you do by applying oil is on the one hand nourish the wood to prevent dehydration.
On the other hand, oil also acts as a water-repellent, so that moisture penetration can be avoided.

There is one thing you should be aware of when using oils.
These will protect the wood from weathering, but not from UV rays.
This means that wood that has been treated with oil can still age from the sun.

Oil is suitable for use for interior joinery, garden furniture, parquet, and softwoods such as cedar and pine.

How to add oil wood finish

You can apply oil with a roller or a long-haired brush.
Nowadays, there are also oils that can be sprayed.

For personal use, always use a stainpad wood stain applicator before applying oil.
That stainpad is super handy for applying oil evenly without dripping.
I highly recommend this and is stainpad is one of the most practical discoveries I’ve made in recent years.

Oil is best applied in three layers.
This can be done on both soft and hardwood.
If your wood has been impregnated or chemically treated, two coats are sufficient.

After applying oil, let it soak in for a few minutes, after which you can rub the surface again with a lint-free cloth.
You can remove all oil residues that are left on top of the wood in this way.

When to repeat oil wood finish

To keep your wood protected by oil, it is best to apply a new layer of oil every 3 to 5 years.
Of course, this depends on the function of the wood and how often it is loaded.

There’s a handy trick that lets you see when a new layer needs to be applied.

Apply some water to the wood.
If the water forms pearls, the top layer is still water-repellent, and you don’t have to apply new oil yet. If not, it is best to apply a new layer of oil.

Wood finish #2 – wax

Wax is a similar product to oil in effect.
The only difference with oil is that it forms more of a top layer and penetrates less into the wood.

You will usually find beeswax in its natural form, but there are also synthetic waxes.
With wax, the grain in the wood remains clearly visible.
The disadvantage of wax is that you can only use it for indoor applications.

Wood finish #3 – stain

If you want to protect wood against weather influences, temperature differences, and pollution, it is best to use a stain.

When you apply a stain to wood, it will soak into the wood and form a layer on top of the wood.
The more layers of this stain you apply, the thicker the film will be on the wood.

Because stain provides impregnation and therefore protects the wood against moisture and weather conditions.
Most of the time, this wood finisher will be used on outdoor wood.
After applying a stain, the wood can continue to breathe, so that no blistering will occur.

Usually, stains are colorless, but there are also stains to which the manufacturer adds pigments that provide color.
The pigmentation makes the product UV-resistant, which prevents the wood from aging.

Then there are also fully opaque stains that ensure that only the structure of the wood remains visible, but no longer the grain.
You can purchase an opaque stain in almost all colors and will actually give the same effect as a paint layer.
The only difference is that a primer must be applied before applying paint and not with an opaque stain.

How to add stain wood finish

In most cases, it is enough to apply two coats of stain.
If the wood still absorbs the stain very strongly after two coats, a third coat can be recommended.

Stain can be applied with a long-haired paintbrush, but there are also stains that can be sprayed.

On certain types of wood, it is recommended to dilute the solvent-based stain with white spirit.
This way the stain will penetrate better.
But to be sure, it is best to check the packaging of the stain you are using.

When to repeat stain wood finish

A coat of stain usually lasts well between 2 and 5 years. Just like with oil, you can check whether a stain still offers enough protection by applying some water.
When the water pearls, the stain still protects.

Wood finish #4 – varnish

As you could already discover above, an oil and a stain will penetrate deep into the wood.
However, a layer of varnish does not do this.

Varnish will protect the wood by forming a layer on top of the wood. Varnish is the perfect wood finisher when you want good protection against scratches.

Those damages, such as wear and scratches, only appear in the protective varnish layer, and not in the wood itself.
Unlike stains, the wood will no longer be able to breathe.
The disadvantage of varnish is that there is an increased risk of blistering.

How to add varnish wood finish

Varnish can be applied with a long-haired brush, roller, or aerosol.
It is best to apply varnish in at least two layers.

By the way, did you know that there are varnishes with an anti-slip layer that are specifically intended for stairs?

When to repeat varnish wood finish

How often you have to repeat the varnishing of your joinery, or furniture, depends on the load exerted on the furniture or on the stairs.

How to waterproof wood

By adding a finish, you can waterproof wood. The finish forms a layer and will make it impossible for the water to penetrate the wood. To know more about waterproofing wood, check out my article, What Is The Best Waterproof Wood Finish (4 Options).