How to Build a DIY Sauna in Your Backyard for $5,600

Step 1: Identify the best location for your sauna build and lay the foundation

For this build I focused on a small flat piece of land on the hill behind my house. It was the perfect whimsical spot to build a custom sauna. First step in the sauna installation was building the foundation. I dug down to fill some concrete piers below the frost line and built up from there.

Step 2: Decking and framing

Step 2: Build a deck and frame out the sauna

Similar to deck/patio building, I framed up a bunch of pressure treated 2x6’s with simpson strong ties tying everything together. From there, I laid out the walls with 2x4’s and connected them to a 2x6 ridge beam. After tying it all together with plywood and insulating with some rockwool, I had the basic structure of the sauna room together!

Step 3: Add the floor & drain

So the floor on the sauna is an intricate one! I followed the rough floor plans from Sauna Times and created an in-depth video on the process. Effectively, you want to build a sloping concrete floor with a drain that opens to the ground underneath, for any water you may pour on the sauna rocks. To create this effect you install sections of wood, which increase by an 1/8th of an inch every 6 inches or so, adding concrete between and above them. It seemed super daunting going into this, but it turned out alright and drains decently!

Step 4: Roof it

For the roof, because I made this curved roof, one of the only options was shingles. I ended up getting about half the shingles for this build for free off facebook marketplace, and with the help of some roofing videos and climbing gear as my safety harnesses, I got the job done.

Step 5: Add insulation, vapor barrier, and wall paneling

For insulation, we used Rockwool and topped it with Reflectix as the vapour barrier. For Wall paneling, I tongue and grooved my own 4/4 cedar that I purchased from a local mill. I ended up spending about $600 on all the cedar for my build, which was a great deal! I definitely suggest asking a local mill for wood before shelling out for more expensive (and often lower quality) stuff from Lowe's or Home Depot.

Step 6: Add the chimney

Step 6: Add the stove and cut a roof hole for the chimney

I went with a Huum Hive Heat 12 wood stove. It’s such a beauty to look at and use. Unlike most wood stoves that go into cabins or wood fired hot tubs, it was fairly portable by just my girlfriend and I. We were able to bring it into the sauna pretty easily and from there, I added the piping by using a plumb line off the roof and eyeballing the projected protrusion. From there I cut the necessary holes to install a double barreled insulated pipe leading out of the sauna. Ensuring I had the necessary clearances, it’s performed wonderfully and safely thus far!

Step 7: Finish up the sauna with some special touches!

I don’t get to make too many structures, so when I do, I certainly love to go a little bit wild. As a skateboarder, I always wanted to try and use some noses and tails from skateboards as siding. After adding epoxy and spar varnish to 160 noses and tails, I had a pretty fun and colorful back to my sauna. Furthermore, on the front, I wanted to try out a crazy wavy pattern with some cedar shakes. With the bandsaw, and a lot of running back and forth to the sauna, I ended up with the whimsical structure I set out for. Couldn’t be more stoked for my first sauna build.

5 DIY Sauna Design Pro Tips aka Lessons I Learned

1. Place windows to maximize views. We currently have a nice big window behind the seating area and backrests, it’s still quite lovely to look out back, but if it’s a full sauna, we just stare outside through the door. If I were to do it over again, I would reconsider my layout and would have had our bigger window in frondt of the sauna bench, so that we could enjoy the view a little more.

2. Beware of dead space! Instead of my peaked roof, I should have made a single pitch roof with a lower ceiling height. I really wanted to build something with a curved whimsical roof, so that's what I did, but it honestly doesn’t make a ton of sense for a sauna. In all structures, warm air rises and collects at the top. In an A-frame style roof, warm air collects at the ridge and that’s generally sort of no-man’s land. There can be a delta of about 15 degrees Celsius between where we’re sitting and the ridge. That heat just isn’t being used effectively.

3. Insulate the outside as well as in. In most modern day builds, adding exterior insulation is pretty key and prevents thermal bridging. In this build I ended up using Rockwool insulation on the inside only. Mind you it’s still way more insulated than a barrel sauna, but on my next build, I’ll also be creating that external thermal envelope that should help a ton too.

4. The floor is a canvas, too. For the interior floor of my sauna I built a custom sloped concrete floor to allow for natural draining, which has worked great, but it’s sort of boring. I would have loved to have used tiles instead. A bit of colorful or unique tile, in my opinion, would make things more fun and match the whimsicalness of the outside and overall concept.

5. Purchase a real sauna door. Instead of building a wonky arched door myself out of several sheets of baltic birch ply, I probably should have bought one. I had to go through a few iterations to make my handmade door fully air tight and if I were to do it over again, picking up a traditional sauna door made of cedar, with a proper door jam, would be a good idea.

BONUS. Don’t forget your essential oils! My partner Amber loves sauna accessories and her essential oils, and brought in some eucalyptus, lavender, and peppermint oils. A drop or two on the water ladle just before going onto the hot rocks is a game changer!