I have been thinking about building a sauna for a few years simply because I love spending time in a sauna and I was looking for a fun project. The sauna was constructed behind my house in Denver, but it will be transported up to the mountains if I can figure out a way to get it on a trailer.
Build a sauna that could comfortably seat four people and last for a long time.
Step 1: Flooring Joists and Decking
To build the floor I used 2x6 pressure treated joists spaced 18". The base of the sauna is 8'x6'6". Then I used 3/4" osb for the decking.
Step 2: Framing
The sauna uses a lean to design with the front being 7' and the back at 6'3". That will be enough to shed the rain and snow without being too tall in the front or short in the rear.
Step 3: Plywood Sheathing
After framing out the wall and securing the plywood, I cut out the door and window frames. I cut the window so that I would be able to look out of it while sitting on the back row and the door was cut at 26". It's a cozy door but I didn't want it to be large and have it take away from the cozy cabin look I was going for.
Step 4: Moving the Sauna and Adding Roof Joists.
After the framing and plywood was finished I rolled it into my alley with 3 1" steel pipes where I began coating the Sauna in tar paper and adding the roof joists. The roof joists came out to a 8.2 degree angle and I cut the "birds mouths" accordingly. The front and rear of the sauna have a double header which is likely overkill for such a small structure but it is easy and fairly inexpensive to make a small structure very very strong so I went for it.
Step 5: Adding Siding
For the exterior siding, I used pine beetle kill. The wood is beautiful and turned out better than I could have asked for. I chose 1x6 T&G siding and used 2" galvanized nails to blind nail all of the siding into the studs.
Step 6: Building the Door
To build a door, I chose to use the T&G to construct a "z batten" style door that has the look of a rustic barn door and is very solid. I ripped the tongue and groove off of the outermost pieces and then did the same for the diagonal and horizontal bracing. This might be my favorite part of the sauna. It turned out beautifully.
Step 7: Window Construction
The window was built by ripping the the bevel edge off of douglas fir 2x4s and then cutting a 1/8x1/8 slot in the frame to seat the three 8x10 glass sheets. This was mounted with hinges so to cool the sauna down when needed.
Step 8: Interior
The interior was built using radiant barrier, insulation and the 1x6 siding used on the exterior. The radiant barrier and blow in eco insulation keep it very warm. I installed the insulation by hand due to the small size of the job. After tacking up the radiant barrier and adding the insulation, the siding was nailed down. The pine on the itnerior has a great smell and feel to it. When you walk through the door, it has a very peaceful and soft feel.
In order to lower the clearance to combustibles, tin roofing was attached to the walls.
Step 9: 2 Month Review
I have used the sauna about 15 times now. It heats up to 150 in about 25 minutes so I'm really happy about how quickly it heats up. The stove is pretty large for the space and it actually charred some of the flooring so I had to raise it up on a layers of bricks and a stainless steel sheet to reflect the heat away from the flooring.
If I were doing it again, I would make it a bit larger so that I could have the stadium style seating in the sauna. I can't do two rows of seating because the bottom row would be way too close to the stove. It is working great though and comfortably seats four people.
Thanks for looking.