Protection of a spruce wood facade

Hello,

we are looking for a natural method to protect a spruce wood facade ([Boden Deckel Schalung]). We don't mind the uneven aging of the facade; it is more about protecting the wood facade without further treatment. The house is detached, exposed to all cardinal directions, with the largest surfaces facing north and south.

Does anyone have experience with treating wood with fungal cultures?
An interesting method would be charring the wood as wood protection. Has anyone ever tried this themselves and can share their experiences?

Thank you in advance.

Basically do nothing. Leave it natural. The wooden facades in the Alpine region or on barns are not treated. If you still want to do something, you can use hydraulic oil. Maybe on the weather side. I use it for the garden fence, it has proven to work very well. I would stay away from any kind of paint. Of course, with spruce you have to be careful about fungal growth. So always make sure that there is no waterlogging or moisture anywhere. Once it is in there, it is almost impossible to get rid of. So everything must be very well ventilated.

We are currently in the process of making an open wooden facade in spruce. The house is also freestanding, which is why our wood supplier said it didn’t necessarily have to be larch. He had that on hand, so that’s what was decided. However, we have the wood in rough sawn form, and that makes a difference. We thought about it for a long time and decided to treat the wood with a graying glaze purely for aesthetic reasons. By now, one-third is finished and we quite like the look; however, unfortunately, we don’t have long-term experience with it yet.
We did underestimate the considerable extra effort required to paint the rough sawn wood; it is partly tough. It also takes more paint than stated. I looked at paint/glaze manufacturers, and they are mostly similar. Actually, I quite like Osmo, but ultimately the deciding factor was that we painted in the carpenter’s workshop and didn’t want to occupy it permanently; painting outdoors in subzero temperatures wasn’t possible with those paints.
We then used Kreidezeit silvering glaze, also because according to instructions it can be applied with one coat.
I have also seen the charring method; it looks stylish. In the end, we based it on what we had on site and could implement.

Thank you for the helpful answers.

Owatrol Textrol. Norway's number one. Also available in [D]. Not exactly cheap, but very good and also economical.

Once coat it and it's fine, or every few years?