Balcony support beams rotted after 9 years

You apparently did not understand me correctly. Where light and oxygen come in, nothing is rotten. Metal covers were installed on the support beams. These were drilled through multiple times due to poor planning and redoing. We think that was the cause. The rot has penetrated under the metal covers.

that is YOUR HOUSE, YOU have to take care of the maintenance, just understand that....

How could we have treated the beams under the metal covers?

So that one knows what it is about, could you upload a photo?

That is why houses are best built from stone and concrete. Steel is also acceptable.

Alright Roswitha, unfortunately, this was not done correctly from a technical standpoint. Under a metal plate, a tar coating must be applied to the wood, then a tar paper on top of that, then the metal on top and bolted. At least that's how they build ship bridges in hydraulic engineering, which are not unlike a balcony. Knallkörper is also unfortunately not entirely wrong. Even wood constructions treated in such a way are susceptible and unfortunately not permanently safe. Since the ban on real Carbolineum based on waste oil, we have a problem there. Karsten