Wooden terrace - Which type of wood to choose, or WPC decking?

Actually, I thought that woods like larch are not treated with paint for the reason that it does not allow vapor diffusion. This causes the wood to rot much faster. In our area, untreated larch façades are not uncommon.

All or nothing, firecracker. Either you paint all sides and seal the wood or you don’t paint at all. Rotting at the edges is a well-known phenomenon with wooden windows. I would never go through the effort of painting for a terrace. On ships, with the constant exposure to water, it’s a different situation. However, the rot problem is always ongoing there as well. That’s why solid wood boats have practically become extinct. Either you use plastic or, if wood, then two-component protected, molded plywood. In the commercial sector, basically only steel.

Since we are currently discussing terrace planning, I’ll chime in here. The terrace is supposed to be about 30m² in size; additionally, another one on stilts, about 8m², will be built next year. The terrace faces southwest, without a roof.

I am now pondering over the choice of suitable wood for the surface.

The options are Douglas fir or larch, which have already been recommended here, or thermopine. Has anyone had experience with the latter?

The decking boards should be laid parallel to the house wall with a slope away from the house, so they should be smooth, not grooved, to allow water to drain properly. Additionally, of course, there should be a substructure without direct wood contact.

I don’t mind the discoloration of the wood; I even find it pleasant. I have bigger concerns about splinters. Sellers of thermopine often claim that it is much less prone to splintering than larch. Does anyone have experience with one or both types of wood? With a smooth surface, I imagine I could simply sand off the top 1-2 mm if splinters ever form, just like with parquet flooring, and then be trouble-free again. Is that a misconception?

Thermokiefer

I can only make thermowood experience into thermo ash. However, the woods are quite similar after the heat treatment. - very dry ==> prone to cracking during processing - very smooth - no splintering Sanding only if you are fastening from below. Otherwise, you will have hundreds of screw heads in the way from above... Oh yes, please pre-drill. The wood will appreciate it and is less likely to crack.

- very smooth

Very smooth in a negative sense? So slippery when wet, more slippery than untreated larch/Douglas fir (without riffles)?

Very smooth in a negative sense? So slippery when wet, slipperier than untreated larch/Douglas fir (without grooving)?

In a positive sense. More or less all woods are slippery anyway, especially if you wear the appropriate shoes and step on the heel. It’s no different with grooving (there it tends to "rot" in the grooves because water collects there).

Very pleasant barefoot. My twins played on it from birth until the age of 5 and none of them complained about splinters.