Timber constructions have received a lot of attention in recent years. Timber is a renewable and sustainable material that captures large amounts of carbon during growth. This has allowed for higher constructions. Wood can be used in many different ways. There are many species with different strengths, nuances and potentials. There are hard woods with similar strengths to concrete and there are also soft woods suitable for other purposes.

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Wood is porous, which is why it is natural and can adapt to any temperature or humidity. It is also able to absorb all substances, including oils, dirt and chemicals. Wood can crack, dry out, lose its natural tone, and become brittle if it is not properly finished. You may see swelling or rotting if you’re exposed to extreme conditions, such as drought and high humidity.

Wooden buildings require more maintenance than any other building. Wood can be preserved with a suitable finish to prevent it from rapidly deteriorating, increase its useful life, and preserve its natural characteristics. Each country may have different terms and availability for each type. Below are the most popular finishes, along with their main characteristics.

Varnishes

© Carlos andre Santos

The word varnish can be used to describe a wide variety of wood finishes. The varnishes form a transparent layer on the surface of the wood. This protects the pores and highlights the wood’s natural colors. It is made from synthetic resins and drying oils. There are many types of marine varnish and polyurethane on the market. They are extremely resistant to moisture and water. You can also find varnishes that protect against UV rays which are very useful for outdoor structures. Some varnishes allow for the addition of dyes to alter the wood’s tone.

Varnishes can be used on facades, structures and frames as well as internal parts. The varnish layer starts to peel away from wood and leaves it exposed, so the piece should be sanded then varnished again.

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Impregnants

Impregnants work in a slightly different way. They penetrate the wood, leaving their pores open. It gives the wood a natural appearance, particularly to the touch. However, even the most transparent version can still obscure the piece. It is water-resistant because it penetrates the wood. It is easy to apply and maintain. The stain absorbs into the wood and doesn’t form a protective layer.

These are used in roofing applications and have similar properties to varnishes.

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Oils

Oil finishes are very popular with carpenters because they highlight the wood’s character without altering its color or texture. They are made from natural products and are easy to apply. They are able to hydrate and waterproof the wood as it moves naturally. It is, however, not as weather-resistant as the other finishes and must be used regularly. Linseed and Tung oils are the most popular oils. However, it is possible to use ‘raw’ oil or polymerized oil. This heat treatment makes the oil more durable and speeds up drying time.

© Kelly Marken

Oils are generally used in areas that have low sun exposure and rain. However, they can be used to protect cooking tools such as spoons and tables. Mineral oils are recommended in these situations.

Shellac

Shellac, a natural finish made from the Kerria lacca beetle (a species found in forests of India and Thailand), produces shellac. Shellac is a fast drying varnish that forms a strong, flexible, and hard film. It can be used to varnish floors and furniture. Shellac isn’t very strong and can be diluted with alcohol or water. This is why it isn’t often used today. It is often purchased in small pieces and diluted with alcohol before being used.

There are still carpenters who use shellac for finishing fine furniture.

Wax

© sergey0506

Waxes can be sold in solid, liquid or paste form and are made from many different vegetable, animal, and mineral sources. Carnauba and bee wax are the most popular. The waxes are applied to the wood as a finishing touch. They do not penetrate the wood but stay on the surface, which prevents oxidation. The wax alone will not protect the wood. It can also be used on areas that have had oils applied. This gives the surface a soft shine, and pleasant sensation. It is not recommended to be used in areas that are exposed to the elements.

© TwilightArtPictures

When considering the options of wood finishes, it is important to consider the following issues: the future use of your piece, its location and expected life span. Sometimes, it is worth considering not using any finishing product. Because there are noble woods that are heavy and hard like Cumaru (Dipteryx Odorata), which has a resin that provides natural protection. The Vila Taguai project by Cristina Xavier did not use any product to the wood. Acetylated wood is another construction method that does not require finishing and has a long life expectancy. The finish of panels on a CLT slab panel will differ from one for a park bench or a piece of furniture intended for indoor use. It is important that architects are knowledgeable about the options and functions of each piece in order to choose the best solution for each situation.