Impregnate larch wood - is that necessary

Many are in doubt as to whether or not they should impregnate their larch wood. Sometimes there are contradicting statements from experts, sometimes protection is recommended, sometimes not. In this article you will find out what is actually true and when you should treat larch wood.

Durability of larch wood

Larch wood is naturally relatively weatherproof and resistant to pests such as insects and fungi. If it is exposed to the weather, larch wood is usually not a problem. Regardless of this, however, a silvery-gray patina forms on the wood over time. This graying is a natural process in which wood (even weatherproof) protects itself against the destructive UV radiation.

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  • Also read - Treating larch wood - you have to do that?

Protection requirements

Basically, there is no need for protection if you can live with the (uneven) graying. Depending on the extent of the weather to which the wood is exposed, it will gray unevenly. This leads to color differences, for example on facades.

Constructive wood protection

When it comes to wood outdoors, the most important thing is clearly the constructive wood protection. The wood must be built in such a way that it is protected from permanent soaking and can dry out again and again. If this requirement is met, impregnation protection does not necessarily have to be applied in order to preserve the service life of the wood.

Protection against graying

In order to achieve protection against graying (the larch wood then retains its original color instead of developing a patina), pigmented wood stains must be used. Most colorless wood protection impregnations do not offer UV protection because they do not contain any pigments. Impregnation usually only provides a certain protection against the effects of moisture (not absolutely necessary for structural wood protection) and against blue stain fungus. There are, however, a few exceptions for wood preservatives.


In order to renew the UV protection components, re-treatment must be carried out regularly, about once a year will be sufficient in most cases. In some cases, more frequent or less frequent post-treatment may be necessary, depending on the intended use and the weather conditions.

Use only tested products

In Germany there is a directory of wood preservatives in which manufacturers can have their products entered after an effectiveness and safety test. This is regulated across the EU. In the case of untested products on the market, neither the effect nor the harmlessness of the product can be guaranteed. Such products (mostly cheap suppliers) should be avoided.

Tips & Tricks Alternatively, you can also achieve an even graying through chemical pre-weathering. There are a few oil stains on the market for this, most of which have the term "Weather Stain" in their names.