Wooden fences - how to choose wood, protective materials, tips

When it comes to wooden fences we don't worry too much about them considering them less important compared to furniture or a house. They seem like they can be made with any kind of wood, that we can paint them with what's left over from other projects. But if you're fencing off a plot of land and you want the fence to look good, when you're doing the sums there's a cost that's not to be neglected. That's why it's best to make it as durable and protective as possible, and the following tips can help.

Why protection? How it was done in the past

Fences are the most exposed outdoor constructions. Houses and outbuildings have a roof, furniture can be put under shelter, the patio is also covered, while fences are directly exposed to the elements. In addition, they can be attacked by insects, get diseases like blue mold or rot.

In the past, some fences were made of woven wicker. The wickers were not cleaned of their husks and this protected them. When they made fences out of planks, they used to make them easy burn. The slightly charred layer on top was very good protection. It wasn't an advanced charring like the one Shou Sugi Ban Japanese method. The burn was shallow and colored the wood beautifully.

Oil or tar was used to protect the plank fences. It was common practice to paint the fence with oil burned by an engine. The pitch was 'melted' in gas and the resulting solution was used to paint the fence. It provided good protection against damp.

It was also customary to paint fences as well as trees. The lime protected against insects and UV radiation. It was washed away by the rains, but was refreshed every summer.

What wood to choose for the fence

But let's come back to the present day and see how to extend the life of a fence as much as possible. 3 things to keep in mind when building a fence:

• choice of wood
• mode of construction
• wood protection

The choice of wood is made taking several criteria into account. In addition to aesthetics, durability and resistance to rot must also be taken into account. Moisture can cause fences to rot on contact with the ground. This area is the most exposed, even more so than the ground, because of oxidation from the air and solar radiation. That's why the best wood for fencing is the wood used in construction.

The wood with the best resistance to decay is tannin and natural oils. Our wood that meets these qualities is acaciaul and is used for the fence posts that are driven into the ground. Oak It is also very resistant, but is less often used for fencing because it is a precious wood that is hard to grow and is mainly used for furniture, but also for doors and windows.

Acacia, although very hard, is fast-growing and is widely used as a building material for strong structures. Often combinations are made, using acacia poles and lighter, less resistant planks of other species.

But the most commonly used wood for fencing is resinous - spruce, fir, pine. It's durable and available, and the resin content helps a lot to stand the test of time. Pre-treated wood is also available, with protection provided by impregnation treatments. This wood is much more resistant to weathering and insect attack, but also more expensive.

What to bear in mind when building

As I said, the biggest problem is rotting. The wood practically grinds on contact with the ground and ends up being blown down by the wind or falling under its own weight. That is why, in addition to using a tannin-rich wood, water drainage and protection of the buried portion must be ensured.

Drainage is ensured if gravel and sand are placed in the pit and only then filled with earth. If the gravel is 'bound' with cement instead of earth, the strength is greatly increased.

Around the pillar the earth should be beaten very well and loaded so that it is higher than the surrounding soil. The water will drain away and so the pole will be protected.

There are also protective sheets that can be placed around the pole in the area that is in the ground. The foil should also remain outside to provide protection when in contact with the ground, where the risk of rotting is greatest.

Materials and modes of protection

Like any wood that sits outside, fences also need to be protected. There are lots of products that can be used: varnishes, paints, lacquers, impregnants, waxes, oils. Whichever product you decide to use, it must be specifically designed for outdoor exposed wood to give it the protection it needs. Unprotected wood changes color over time (due to UV radiation) to gray, and resinous wood is the fastest to change color (color change starting immediately after cutting). To preserve its color, it must be covered with materials containing UV protectants.

As far as insect protection is concerned, you should know that these products are not as easy to find as they used to be. There used to be complex products, a sort of 3-in-1, which were insect fungicides, protected against the weather and UV radiation, and colored. Because of the EC requirements for dangerous products - biocides - many manufacturers have stopped producing such materials and have limited themselves to coloring and UV and weather protection. In specialty shops you can find insectofungicidal products that you can treat the wood with before any other type of protection.

But you can buy the wood ready treated against insects. In the past, it was recognizable by its bluish-greenish color. The product that gave it that color has since been banned (copper cobalt arsenate CCA) and now treated wood is only slightly darker in color than untreated wood.

Recommendations on materials used

And we come to weatherproofing. My recommendation is to use products that don't film, i.e. oil, oil-based varnish or wax-based varnish (impregnants), even if you are told that varnishes and paints last longer.

The fence stands all day in the sun, rain, snow, wind and whatever else it has to endure. As you know wood varies in size depending on the humidity outside. If it's covered with a film, it's possible that movement can cause the film to crack. At that point the protection ceases and water seeps under the film, causing it to flake. The appearance will get uglier and uglier and you will definitely want to refinish. To refinish it, you will have to remove any remaining traces of varnish or paint.

If you apply oils or waxes, they do not film. They go deep into the wood and protect it. What's left on the surface will wash off in the rains, but it won't look ugly, like peeling varnish. Plus, the protection inside the wood remains. The finish can be refinished without having to remove the old layer.

One important thing to keep in mind is that perfectly transparent products do not protect against UV radiation. That is why outdoor products, even if they are transparent, are slightly tinted. It is the pigment content that protects. Use linseed oil or wax-based varnishes because they contain such pigments.

There is a type of wood that does not need special protection. This is treated and stabilized wood that has no dimensional variations. But it is much more expensive.

In conclusion:

• Use durable and rot-resistant wood. Wood containing oils, tannins or resins is recommended.
• Adopt constructive solutions to drain water from the base of the fence.
• Choose designs that don't let water soak into the wood.
• Use protective materials that don't film - oil, wax - you'll find it much easier to maintain.
• Don't use totally transparent products as they do not protect against UV radiation.

I hope these tips will help you build strong and beautiful wooden fences. Good luck!