@freemo The heat in the Furo tubs must be nice too, would love to try it. A Cedar one, specially, which must smell good with the hot water in it.

@design_RG I feel like the wood would also hold a lot of germs. But it must smell nice and I guess if they added some kind of lining it should be water tight on the inside at least.

Noty sure if these get any hotter than a normal hot tub though.

@freemo @freemo Wikipedia has a short page about Furo, or Ofuro as it is also called. I have heard the water is quite hot, here's what they say:

https://en.wikipedia.org/wiki/Furo

"Furo are part of the Japanese ritual of bathing, not meant for washing but rather for relaxing and warming oneself. Washing is carried out separately outside the yubune. The bather should enter the water only after rinsing or lightly showering. Generally Japanese bathrooms are small by Western standards, so the bathroom is set up much like a walk-in shower area but containing the furo. Since the bathroom is a complete wet area, in modern buildings and ryokan heating is provided by air conditioners overhead. The water is hot, usually about 100 to 108 °F (38 to 42 °C).

@design_RG Water tub temperatures here are usually set to 102F

@freemo The tubs are water tight by their construction alone, I believe, similar to wine barrels. Wood should expand a bit when wet and hot.

I built a shower stand many years ago in cedar slats and it was lovely - the smell, the texture of the wood under my feet. Left the wood untreated, and curiously, the common nails did not rust, protected by the wood's natural oils.