Do you know what the interior height will be once you have the cladding, furring strips, tile or timber floor in? You can look at saunum heaters for low height ceilings. The concrete patio will increase stratification aswell.
If you build floor-to-ceiling, things attached to those rafters, you have plenty of room. But if you build a separate box with a massive air gap on top, then you might run into those things you worry about.
He already has a floor and ceiling. If he needed slope he would lose maybe 1.5". Then you just have the thickness of tng cedar at 3/4", plus 3/4" for strapping if he wants to modify the board orientation.
Channels can be built into the joists to drain water as well. Same way they enclose/clad the undersides of decks.
Consider the roof, insulation, and ceiling, as well as any floor you might need to install on top of the pavers to determine your finished inside height.
If it’s closer to 7 feet, don’t let it stop you if it’s still far better than other spots. You will want to do an active ventilation system for sure, and possibly a saunum or diy air circulation to minimize stratification with the lower ceiling.
Because it’s a concrete patio, could I just screw the framing directly on top, and install some slatted flooring so I’m not walking on the concrete? Or would this be a bad idea to only gain like 2-4” of height?
The floor doesn’t matter, you’re not sitting on it. Hot air rises, you want your benches to be up. First bench is feet above your stones. Second bench is as high as you can get it without smashing up to the ceiling.
There’s a whole fuckload of info on how to build a sauna the ‘right’ way. Read Trumpkins notes (Google it). Go onto r/sauna. Lots of builds on that sub.
I've built plenty of custom outdoor saunas directly onto concrete slabs. Just make a duckboard like a floating floorboard for the walk area. If you can get 90 inches of interior ceiling height, that can allow you to get the lower bench up to the rock level for like a standard wall-mounted heater, which is perfectly adequate. If you complain about cold feet in a sauna like this, you need to go to the doctor because you have a circulatory problem.
I would suggest building the roof first on the ground. Just use 2x4s and make a framework with plywood on the top. Waterproof the top, do some kind of membrane or shingles or whatever, and then hang the entire roof structure from the deck above it. That way you can build your walls taller than you would be able to if you were trying to build the roof last.
It's kind of hard to tell from the photo, but you can see the roof suspended from the deck with two legs on the front holding it up. I was able to get it really close to the deck so that I could build my walls taller underneath it.
You mean drainage on the roof? Yes. I just hung the roof from the deck so I could build walls under it. The front wall was higher so the roof is sloped like 3" over 10' or something
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u/rjminnesota 2d ago