- 8×12 structure
- 6×8 sauna room*
- 6×8 changing room
- Dual benches on either side.
- Stove centered along the back wall.
- 2×4 framed construction
- 5/12 roof pitch
- Put a window in your sauna if you have a nice view.
I have been in several hundred different saunas. In each sauna, I have sat on the bench and have considered what’s good, bad, and ugly with the design and construction of each one.
Some saunas are two person saunas, and don’t allow for a good sauna party. Some saunas are bigger than a four person sauna and take too long to heat up, use too much energy or wood. Often, in sauna hot rooms that are too big, the loyly (steam from tossing water on the sauna stove rocks) never reaches you. With divine proportion, according to the Greeks and confirmed by Da Vinci, this 8’x12’ sauna design is my ultimate sauna plan.
This sauna design uses North American standard measurements, minimizing waste in construction and allowing for full cuts of material. It provides a changing room, which is a critical space for privacy and enjoying a beer or libation between rounds, while also serving as a buffer for temperature extremes in cold climates.
- Frame the interior wall with 2×2’s vs. 2×4’s- just sheath the wall with 1/2″ plywood for rigidity. This is a non load bearing wall, and the extra 1.5″ sure is valuable!
- The interior wall can be nudged slightly to allow for a slightly bigger sauna room (say 6’2″x7’4″ interior dimensions). Four people can fit nicely along a 6’2″ bench, and it’s nice to lay along your sauna bench. A comfy sauna and ample changing room is the goal. Having a bunch of people over for a sauna party? Don’t sweat it! Click here for the sauna party equation.
The 3D drawing above may not be the best stove placement. Thanks to Adam’s comment below, here is arguably two different configurations each offering advantages of:
- more standing space.
- less staring at each other on the bench vibe.
- less bumping into the stove ouch.
- asymmetrical flow, best discussed between rounds in the garden all misty wet with rain
My 8×12 sauna plan assumes a wood, not concrete floor.
- 2×6 green rim joists.
- 2×6 green floor joists at 16″ or 24″ on center.
- 3/4″ subfloor, et voila.
Stephen, I know your sauna has a cement slab, and i’ve built a couple saunas with a cement slab base (which could be argued is the “A” job) yet I find with a wood base to your backyard sauna it can be:
- built quicker.
- leveled easily, even down the road.
- moved if you move, or if your partner gets wiggy.
- called a ‘temporary structure’ for frowning building code inspectors.
- extended easily as a header for a deck (yet I prefer a slate patio with an outdoor sauna, so as to reintroduce the stone medium from sauna rocks to your feet whilst between sauna rounds).
As mentioned in this video here, many country and lakeside saunas don’t have electricity. In Finland and everywhere, many traditional saunas were built before electricity. Also, many saunas are built away from the main house, cabin, or cottage. To the positive, this reality is what helps make the sauna building a true escape: a step back in time and towards simplicity.
Saunas that have been lit exclusively by candle or lantern may now, with the flick of a switch, be powered up like the LM in Apollo 13.
A simple hot room light, a couple wall sconces in the changing room, and an outdoor patio light is all that is needed (the power of three). Oh, and put ’em all on dimmers. One can bring power into the structure by wiring an RV electrical plug (expensive) or a simple male plug tucked under the structure outside. The system can be tested and powered for sauna parties by running extension cord from the nearest power source.
Run 12/2 wire from the outside plug under the bottom plate directly to a GFI outlet, then run power to lights and additional outlet(s). This keeps your entire system safe from power surges and accidents eg. when a drunken guest thinks your triple light switch is a sink.
Here’s a simple foot friendly outdoor sauna foot mat. I especially like standing barefoot on this cedar slat mat in winter time. The snow, ice, and cold water seep into the ground and my feet stay fairly dry. This floor mat feels much nicer than a plastic floor mat. Just rip some slats from a cedar board or maybe purchase some 1×1 or 2×2 cedar boards from a lumber yard, attach a couple cross supports underneath with a finish nailer, et voila.