Paint wooden beams outside with or without impregnation


Apart from the optical state, wooden beams in outdoor areas usually take on a static function. Outstanding roof parts of a roof truss, the roofing of a garden shed or a shed and a carport construction are the most typical examples. Brushing is often a part of the protection required by the building authorities.

Primer with or without impregnating effect

In order to paint wooden beams outside durable and durable, the substrate must be prepared. Weather influences, insect infestation and UV radiation are the three major influencing factors that a painting must withstand. It can be distinguished whether the painting

  • only need to protect itself or needs color-related durability or
  • an additional function as wood protection in the impregnating sense must exercise.

Painting the beam requires in both cases a primer, also called wood base. While the primer without impregnating effect can be selected largely free of chemicals, must be selected for the treatment against external influences both chemical wood base and correspondingly resistant color or glaze.

Types of wood and impurities

Coniferous plants must always be impregnated with a coat of paint, while most deciduous and all tropical woods are only "dyed". The absence of impregnation is also possible by sanding the wooden beams, which reduces the sapwood content to less than ten percent.

To give the paint the necessary support, a thorough cleaning of the wooden beam is an indispensable prerequisite. Depending on the condition and types of contamination, such as bird droppings, painting can be ideally prepared by sandblasting the wooden beams. If the wooden beams are to be painted, especially boat paints offer a high resistance. Of course, all loose surface parts such as splinters, split pins and loose fibers must be removed. Weathering traces must be removed down to clean heartwood.

Colors and wood ingredients

In the wood are components such as acids and resins, which can lead to a reaction with the applied color. In particular, bright glazes and water-based paints must also be protected by an insulating base against these reactions and the resulting discoloration.

Tips & Tricks

For beams of a roof truss, the protection regulations according to DIN 68800 apply. Before painting, find out whether the paint method you have chosen meets the requirements of the legally required wood protection.


Video Board: Durable Outdoor Finish