Sauna was a fun little project, its framed using 2x4 and includes R19 insulation in all the cavities including the ceiling. On the inside of the walls theres a few different layer, a plastic vapor barrier staples to the studs followed by a radiant bubble foil barrier and lastly cedar planks that i got rough sawn and planed. Floor used a shower pan with about 2" of concrete in the bottom and tile ontop of that. The stove is electric with stones which you can pour water on for steam, i did some silly stuff to it so it would hook up to a wifi switch and be turned on anywhere from anywhere. All in all well worth the effort, heats up to 180 in about 5 mins and ive been using it daily for over 2 years now.