ᐅ Durable hardwood, locally sourced decking boards

Is it thermo-pine?

20 years is not much when it’s over ... :p
But usually, you would probably expect an even shorter lifespan.

For oak – which is among our most durable woods – I quickly found the following entry: lifespan: 10-15 years

.... what bothers me a little now (while researching) is the reduced stability of thermo-treated wood. The distance between support points should not exceed 50cm (20 inches). (There is little information regarding the thickness/strength of thermo-wood...)

manohara schrieb:

Has anyone installed this "between us" and can share their experience?

Thermo ash used for almost 10 years. Apart from graying, no signs of damage. When moving out, it still looked like new. Very hard wood – please pre-drill, the wood is brittle. 60mm (2.4 inches) spacing was sufficient for something around 25mm (1 inch) thickness.

The "Dauerholz" people seem to have disappeared completely... their website is "temporarily unavailable," and the phone number I have is "unknown."

manohara schrieb:

It seems the "Dauerholz" people no longer exist... the website is "temporarily unavailable" and a phone number I have is "unknown."

I noticed that too, which is not exactly a good sign.
Why don’t you just use the raw wood as the surface, like it is done in Scandinavia, the Alps, or elsewhere? Anything you do to it wouldn’t really be ecologically sensible in itself, whether it’s oil, wax, or any other treatment.

Wax is less environmentally friendly than no wax at all. Unfortunately, you are probably right about that.

For me, a key criterion is whether materials stay within the "natural cycle" (unlike plastics). According to Wikipedia: Stearin (which is in the thermally modified wood) is produced 100% from plant-based or animal-based renewable raw materials and can – unlike petroleum-based paraffin – ideally be considered carbon-neutral. However, they do limit this by noting that stearin can be produced either from plant sources or from petroleum... Whether it is "toxic" to the environment is unclear to me, but it does not sound like it.

An alternative to wood is a material that is supposedly "wood-concrete," waterproofed on the surface with plastic. With this, I might (perhaps) never need to do repair work in my lifetime... But I only like this from a convenience point of view... visually and in terms of feel, it is quite limited.

... and yes, you are also right that it makes sense to look around at how other people in the world solve this problem... 😎