Professional wood coating - Instructions and tips

Why does wood need to be coated?

Wood is a hygroscopic material. This means that wood absorbs moisture from its environment (rain or humidity in the air). If there is too much water, the wood swells and is damaged. Accordingly, if left untreated, wood has low dimensional stability. In other words, it does not withstand changing environmental conditions well. Wood is also an ideal home for various pests. On example is the larvae of the common rodent beetle, or woodworm, a dry wood pest that eats its way through structural timber.

Outdoors, moss or fungus can attack wood, feeding on the lignin and cellulose inside the wood. This eats away at the components that preserve the structure of the wood. This not only means potential danger to people nearby due to the wood's diminished stability, but it can actually also be harmful to health. And finally, wood also burns easily. With a fireproof coating, this safety risk can be avoided.

Since pests and the effects of weather can have dramatic effects on the stability and longevity of wooden components, you should coat timber based on what it is being used for: with suitable coatings that are adapted to the type of wood and how it is being used.

What coating materials are available for wood?

There are various materials available for coating wood. They can be differentiated into film-forming wood preservatives, oils and waxes, synthetic resins and other coating materials.

The film-forming wood coatings include varnishes and glazes. The difference lies in the two coating materials' permeability. A protective glaze for wood still allows the diffusion of water, in other words, the wood is still able to give off moisture. Varnishes, on the other hand, completely seal the surface so they become impermeable. Both varnishes and glazes can be used to achieve cosmetic effects. Chemical substances such as UV protection, fungicides or pesticides are often added to varnishes and glazes. Today, the trend is increasingly moving towards solvent-free varnishes and water-based glazes since they are better for our health and the environment.

Oils and waxes, however, are often based on natural ingredients and are also used for coating wood: Furniture is usually treated with these types of material. They close the pores and form a seal that protects against stress, marks and moisture.

Synthetic resins are industrially manufactured resins. Once they have hardened, they form a solid plastic that does not melt. Synthetic resins, just like varnish, are also used to create a complete seal and also protect against mechanical stress. Epoxy resin is used to coat wood and make it waterproof. Coating wood with epoxy resin is a practice that is used for plywood, laminate or even in boat building.

The choice of wood coating depends on a number of factors:

• Which wood has been installed?
• Will the wood later be used indoors or outdoors?
• What is the environment like? Is it dry or damp? Is the surface exposed to constant sunlight?
• If the wood is exposed to significant stress, such as physical impacts or temperature fluctuations?
• Are cosmetic changes going to be made?

Our WAGNER spray devices are ideal for spraying all of the wood preservatives we've just mentioned. In our WAGNER Spray Guide, we have tested all kinds of wood coatings and manufacturers. You'll find the ideal settings for the device and whether dilution is advisable in this guide.