Special order printed lumber?

[HSP]

https://www.rundvirkeindustrier.se/kontakt/

These perform impregnation in southern Dalarna.

https://www.poles.se/produkter/specialanpassat-virke/

These are located in the same place and cut timber to the desired dimension. And they can arrange impregnation.

Have no idea about prices.

 

[Lutte]

You haven't considered, for example, staining the top with oil and then oiling the rest with a clear oil, maybe even submerging it in an oil bath and letting it soak. The cost shouldn't escalate too badly if you buy oil in larger containers.

 

[Danne_83]

For the small amounts, it probably won't be worth complicating things. Treat untreated wood yourself with some oil and leave. Replace a little more often if necessary.

 

[cpalm]

For the small amounts, it's probably not worth complicating things.

It remains to be seen how expensive and complicated it becomes. There is, of course, a limit. But it can't be ignored how extremely cost-effective it is to have printed from the shelf (even cheaper than unprinted).

The existing floor is of course oiled, but I doubt it adds much in terms of longevity. Cosmetically, it has kept the surface fresh, but the rot is a few millimeters down where the treatment doesn't penetrate (which makes it a bit deceptive).