Why should wood be protected and how to do it correctly
Wood is a living organism and remains as such even after we add useful value to it. When exposed to humidity and temperature changes, different types of wood will swell or shrink to a larger or smaller extent. Ultraviolet rays decompose the lignin in wood, which thus becomes gray, rough and dry. It is infested by wood insects and plant microorganisms, among which the ones that are most harmful in our environment are the wood fungus, brown rot and blue mould. Unprotected wood ages faster and looses its quality and aesthetical value, so it is essential to prepare the surface correctly and choose a suitable coating product.
Pick a sunny day for painting, with no rain or fog, as high air humidity can have a negative impact on the drying of the coating. We recommend not painting objects in the morning when they are still covered in dew, but rather waiting for them to dry and warm up to the ambient temperature. Grease and similar impurities should be removed with a suitable cleaning agent or thinner prior to painting. Old paintwork that no longer adheres to the surface should be completely mechanically removed, using paint removers or heat. If you only wish to refresh the paintwork, it should be cleaned well and slightly sanded. Wooden elements, in particular those located outdoors or in humid places, must be protected with an impregnation agent that offers protection against biological influences, before they become infested with wood pest. Impregnation itself does not provide a comprehensive protection of wood. After applying the impregnation agent, wood must always be painted with a top coat which offers sufficient protection against weathering.
Top coats protect and decorate wood and completely cover its texture, and are therefore most suitable for the decoration of lesser quality or damaged types of wood, the renovation of old simple furniture, windows, doors, and fences. They are distinguished by their simple use, quick drying, resistance, suitability for wood protection and possibility of choosing among numerous colour shades.
Woodstains, on the other hand, are transparent coatings which form a thin, transparent elastic film on the surface. Transparent micro-pigments penetrate into the wood together with the binder, and protect it against the effects of the environment, while preserving and emphasizing its natural texture. Water-resistant substances prevent the penetration of water into open wood pores, and consequently the appearance of cracks and swelling of wood. Tinted low-build woodstains in several wood colour shades also serve as a stain for wood and are an excellent base for lacquering. For the protection of wood in sun-exposed places, we recommend colour shades of medium intensity, as the durabilityof the coating and the protection of the object will last longer.
To preserve the wood’s properties, we recommend regularly checking all wooden surfaces. Under normal exposure, it is sufficient to check the wood once a year. Special attention should be devoted to horizontal surfaces that are more susceptible to weather conditions. It should also be noted that wooden surfaces on the southern and western sides are more subject to exposure compared to those on the northern or eastern sides.
Special attention should also be devoted to joinery damaged as a result of hail, as we usually tend to notice it only once the damaged spot has turned gray or after it has been infested with blue mould. In such cases, we recommend protecting the damaged spot with a woodstain coating (e.g. colourless). This should be followed by a full coating renovation as soon as possible.
Advice for the task and selection of a suitable paint:
- select the right woodstain or top coat for the product you are painting by taking into account the product descriptions and the instructions on the packaging, and take into consideration the conditions it is exposed to;
- when coating overhangs and panelling, we recommend impregnating wood from both sides, as this achieves a better dimensional stability;
- colourless woodstains with no UV filters let through a lot of ultraviolet rays which decompose the lignin in wood, which consequently leads to the wood turning gray; therefore, we do not recommend using them as an independent coating for outdoor wood;
- when renovating old woodstain coatings, choose a lighter shade from the one originally used, or mix the original shade with a colourless one of suitable quality;
- if possible, objects to be painted should be in a horizontal position;
- objects that are attached should be painted back to front, and bottom to top (e.g. fences);
- mix the product thoroughly prior to each coat;
- as the type of wood significantly affects the final shade, we recommend testing the product on a small area of the surface you are planning to protect or decorate;
- perform the test on a small part of the old paintwork prior to painting, to check whether the new woodstain will dissolve or soften the old one;
- apply the paint in several thin layers and according to the time intervals stated in the instructions;
- when painting large surfaces, paint the entire surface at once – do not interrupt the work;
- the number of woodstain coating layers affects the shade – each additional layer will make the shade darker;
- any stains that should form while painting are to be removed with NITRO or TESSAROL thinner while still fresh;
- wash the tools immediately after use using a suitable solvent (water or thinner).
Frequent mistakes in wood protection and the reason for their occurrence:
- poor adherence of the coating – poorly cleaned surface and presence of grease
- rough surface – omitting to sand the wood or the first layer (impregnation or woodstain)
- the coating cracks, there are hairline cracks and wrinkles – the coating was applied in one thick layer
- peeling off – poorly cleaned surface and poorly removed old coatings which no longer adhere to the surface
- quick “graying” of weather-exposed wood – wood was protected with colourless woodstains with no UV filters or with insufficiently thick coats
- inadequate shade – the product was poorly mixed prior to use, influence of the surface colour on the final appearance of the coating
- darkening of the shade – the wood was not sufficiently dry prior to painting
- appearance of lumps on the surface – unclean tools, poorly cleaned surface, mixing solvent- and water-based woodstains
- appearance of bubbles on the surface – using inadequate or poorly cleaned tools
- spotty surface – uneven application of the coating
- soft and non-resistant finishing layer – individual layers were applied too quickly one after the other
- the coating does not dry – chemical paint removers were not rinsed, the humidity is too high or the temperature is too low