Barrel Sauna Guide

Purchase Sauna Heaters, Accessories and more at my shop! https://www.saunart.us

Build Plans: https://www.etsy.com/listing/987454770/barrel-sauna-woodworking-plans

I made a quick high-level video for some visual aid (first build): https://youtu.be/I2lJIF8Jus4 

NEW: 

Staves video (second build): https://youtu.be/GQ9n5ywjxks 

Walls video (second build): https://youtu.be/Mr3eUd-45kU 

Cradles, benches, assembly video (second build): https://youtu.be/dTfpbz2dT3w 

NOTE: this guide is mainly based off the sauna build from the video. New "UPDATE" text has been added for adjustments I have made on later builds. New videos are in the works.

Step 1: Size and Planning

Unless you think multiple people will consistently want to be using this sauna at the same time or if you really want to be able to fully stretch out, I would go with a four-foot deep, two-person sauna. I am 6’4” and I feel very comfortable in the space. Additionally, I created a bench that lays perpendicular across the two side benches that I can stretch out on. I still can’t lay completely stretched out, but with my knees bent it works just fine. Most of the time I like to sit up anyway. 

Other factors to consider are the time to heat, heater size, sauna footprint and electrical bills. A smaller sauna requires a smaller heater and may take less time and money to keep heated especially in the winter. It will also take less space in your yard and you will have more flexibility in its placement.

My sauna setup takes about 45 minutes to be at maximum heat on an average temperature day. This will vary based on the temperature outside the sauna, the size of the sauna, the size of the heater, and the consistency and fit of the routing joints. 

When you have determined your sauna size, take a piece of paper and start drawing out the dimensions. This will give you a guide as you build your project and help plan for materials.

Step 2: Materials and Tools (2 person sauna)

• Lumber 

  • Western Red Cedar for best quality, durability and scent.

  • I went to a lumberyard and paid $1100 for 50 2x6x8 #2 (knotted) smooth boards. Guessing this cost can be brought down quite a bit depending on your lumber yard. I went with the smooth because I didn’t want to have to bother with smoothing out the wood myself. I didn’t go with clear (knotless) boards to save money. Clear boards will look better, be more durable and have a better seal. 

  • Go for a few more than 50 if you want some wiggle room. I had to get creative with the scraps at the end for the benches.

  • Side note: It appears many barrel sauna manufacturers use 1-inch wood on the walls and 2x4’s for the staves. So there is some flexibility here. Just plan accordingly with your calculated circumferences, router bits, etc. I am glad I went with 2” for the walls for better structural strength and going 6” wide on the staves and walls saved a lot of routing time and energy.

  • Additional 1x4x8 cedar boards were purchased from Lowes for wall and bench supports.

  • Do not use pressurized or any chemically treated wood. This would be dangerous for your health. 

  • UPDATE: latest build used rough wood and I planed it to my desired thickness. I am pleased with the results and saved money on the wood. 

• Sauna Heater

  • 4.5kw Finlandia FLB sauna heater https://amzn.to/2DgjuOE 

• Other materials (in no particular order):

  • Jigsaw https://amzn.to/3hJgvNI  

  • Miter saw https://amzn.to/31HK5xy 

  • Circular saw (not a necessity) https://amzn.to/2QEj3ko 

  • Drill - https://amzn.to/3bcJWVH 

  • Pipe Clamp  https://amzn.to/3lAtHGP  

  • Pipe for pipe clamp: at least 7ft long. ¾in pipe (lowes/home depot)

  • Sander https://amzn.to/3gHwJ8O 

  • Extra clamps https://amzn.to/34MQzx5 

  • Eye protection https://amzn.to/31M65rb  

  • Dust masks 

  • Gloves

  • Router https://amzn.to/36HAxW1 - updated due to previous one not having .5" collet

  • Router bits -

Make sure to get the appropriate sizes. I used .5” radius and recommend .5” shanks to avoid snapping them. I snapped two 1/4" shank radius cove bits before going with the .5” shank rounding over bit. UPDATE: With my latest build I used 1 1/2" bits (see below)

• • • Round Nose bit (Cove) - https://amzn.to/2ENOnKC   UPDATE: new bit used on later build -  https://amzn.to/2YOUO7p 

    • Rounding Over bit (Bead) - https://amzn.to/2QCdRgT   UPDATE: new bit used on later build - https://amzn.to/2DaPNyi 

    • Double Flute Straight bit (Dado) - https://amzn.to/31JqrBj  UPDATE: highly recommend using a table saw with dado blades if you have one. The router cuts for the dado joints cause splitting and are difficult to get accurate. If you do plan on using a router bit I recommend matching the diameter of the bit to the thickness of the wood to avoid having to do multiple cuts.

    • UPDATE 1/21: Straight bit used for groove cuts on wall pieces - https://amzn.to/3oGFqF9 

    • UPDATE- Comparison pictures can be seen at the bottom of the page.

• • Router Table https://amzn.to/3b8OQ6a 

  • Shopvac

  • Tape Measure

  • Stainless steel screws (2 lbs)

    • Other screws can rust or have chemical vapors so I used exclusively stainless steel.

  • Wire rope https://amzn.to/31FoXaY  (length = outer circumference, mine was around 226.19in x2 ropes)

  • Wire rope clamp set https://amzn.to/31Gwq9H 

  • Turn Buckle x2 https://amzn.to/2EFjg4f 

  • 240v outlet 

  • Type 10 wire (from heater to outlet)

  • 2 door hinges 

  • Door handle

  • Level

  • UPDATE: latest build I planed the wood with this 13in Dewalt Planer https://amzn.to/34M2cEl 

Step 3: Routing

• • Router table setup

    • Ideally you can mount the router table on another table to avoid having to bend over on the ground like I did in the video. 

    • If you are using the router table fence (needed for the cove and dado cuts), always set the proper length tightly on both sides of the fence for consistent cuts. These may loosen over time and need adjustment. 

  • Router depth

    • Depth of the router will need to be adjusted based on the length of your router bit from the router. This took a lot of trial and error with my lack of routing experience. 

  • Process

    • UPDATE: see new bit sizes above. Comparison pictures can be seen at the bottom of the page.

    • Cove: I attempted doing this with a ½ in radius cove bit and got through about half of my wood before breaking two of the bits and a collet extension and nearly giving up on the entire project. I ended up driving to my local Woodcraft store and bought a ½ inch shank semi-circle rounded nose cove bit which was much much easier and I could have saved many hours if I had started with it. This bit does put a lot of stress on the bit though so make sure you have a ½ in shank and are using a soft wood like Western Red Cedar. Follow the RPM guidelines for your bit to make sure you aren’t going too fast. When I slowed mine down to the recommended speed things started working a lot better. Pass through and least twice for consistent cuts. 

    • Bead: standard ½ in diameter bead bit. Pass through each side at least twice. It may not seem like you need to pass through multiple times, but go ahead and do it and see what I mean. I read somewhere that the wood bends a certain way which prevents it from getting cleanly cut the first time through.

  • Pro tip: leave one 8ft board without a cove and one 8ft board without a bead. These will be used for the end wall pieces and will allow the staves to fit better at those spots.

  • UPDATE 1/21: Walls used tongue and groove for the second build and on. I used the same bit as the dado cut (straight bit) and just measured it from the wall so i had a center tongue of .5in. This requires two passes on each side. The groove cut was used with a .5in straight bit. See walls video  for visual: https://youtu.be/Mr3eUd-45kU 

Step 4: Front Wall (entry)

• • Circle 

    • Homemade beam compass

      • I took a straight piece of wood and measured 3ft. I cut it to 3ft minus the thickness of my pencil. I used the flat Home Depot pencil which made it easy to tape securely to the end of the piece of wood. Then I took my caliper and taped it to the other end after setting the caliper depth to equal that of the pencil depth below the wood. The metal point of the caliper made a nice anchor for the compass.

    • Lay out 14 boards which should be routed with cove and bead sides. Remember that the end pieces can be flat (unrouted) for a better seal on the staves. I put the boards on some 2x4s so that The wall would be elevated from the tables when I was doing the cutting.

      • UPDATE 1/21: I switched to tongue and groove for the walls on the second build. Both methods function the same, tongue and groove just looks cleaner if done right.

    • Pipe clamp the boards together near the center

    • Draw your circle. 

      • Make two passes to ensure the anchor was set through the whole circle and you have a consistent line. It is very important for the walls to be the same size and shape for the stave fits and overall look of the sauna. 

    • Additional cuts for minimal wood usage

      • Measure the ends of the circle and cut boards to fit in the circle. This will end up saving two full boards at least depending on how efficient you are. I would have ran out of full stave wood pieces had I not done this. 

  • Door supports

    • The four middle pieces of wood made for a center placement of the door in my case so I cut alongside the edges of those 4 pieces. Make sure that your door cuts are in the center of the circle. 

    • I estimated that 7inches would be a good fit for the length above and under the door. Not too low to allow for more stability in those areas and not too high to make it easy to climb in. 

    • I placed three wall supports wide on the door and two diagonal supports in between. I used one screw per board underneath the supports to ensure the boards stayed tight after removing the clamp. 

  • Wall supports

    • Next I layed out three longer supports wide across the wall with 4 diagonal supports in between. The distance was adjusted to ensure the end pieces got enough support.

    • One screw for every board underneath to ensure tight hold. 

  • Door cut

    • Took the circular saw and cut the rectangle around the door supports. Because I could use the edges of the four center pieces it was very easy.

    • I saved the bead piece that gets cut off on the one side so that I could screw it in later as a sort of adjustable door seal. 

  • Jigsaw

    • With the boards all secured with screws and the door cut out, now begins the fun part of cutting the circle. I rushed this a bit which 

caused an angled and uneven cut around the circle. This wasn’t a huge deal since the dados in the staves covered it up nicely, but I recommend going very slow to ensure a better edge and ultimately a better seal among the staves.  

• • Once the circle was cut, the sauna finally begins to feel like it is taking shape. Your friends and family will finally begin to understand what the heck you are building. 

  • I simply propped it up on the ground and rolled it out of the way to begin the next wall.

  • Note: If your support starts splitting from the screws either get a new board or screw a little further down from the split or else it may split the whole length of the board. Pre-drill to avoid splitting.

  • UPDATE 1/21: New video uploaded showing my process here https://youtu.be/Mr3eUd-45kU 

Step 5: Back Wall

• • Circle - see steps above

  • Clamp - see steps above

  • Supports - same as the last wall except without a door cut and extra door supports.

  • Jigsaw - See steps above

Step 6: Staves 

• • Cove - see steps above

  • Bead - see steps above

  • Dado

    • The dado cut can be done using your straight router bit or dado blades on a table saw. My bit was just short of the exact width I needed so I had to do two cuts on each side. Exact measurement is very important here, I had to reroute many pieces due to rushing this part. 

Step 7: Cradles

• • A tough piece to the sauna build, the cradles are a test of patience. You may have to use your own creativity here. There are a few pictures in the video that should help give you an idea of what to do. 

  • I started with a 4 2x6x51” boards (I used a 2 non-cedar because I had to start saving some wood)

  • Next, I drew a circle with two boards stacked on top of each other. The circle should be slightly larger than your wall compass to factor the staves on the outside of the walls. 

  • From my cuts, the longest point on the top pieces of the cradle is one foot, with the cut only going a few inches deep into the bottom piece.

  • Do this for all 4 cradles.

  • Glue the top pieces to the bottom pieces. I also added a couple screws to anchor it. 

  • Glue (or screw) two cradles together twice to make two sturdy cradles. 

  • UPDATE: on the latest build I used 2x10's to avoid having to glue boards. I simply made the circular cut and screwed two cradles together as before to make them thicker. 

Step 8: Assembly

• • Find a flat space in your yard, house or garage. If possible, make an exact level area with cement, gravel, brick, etc. 

Place the two cradles a little less than four feet apart. Place one stave in the middle with a label to ensure it is level. I used wedges to adjust the level of the cradles. 

• • Fill the remainder of the cradles with staves. 

  • Place walls in dados. Recommended to have some help, but I was able to do this alone so it is possible. 

  • Place one stave on top to help secure both walls from falling over.

  • Make sure supports and doorway are level on both doors. I skipped this step and had to start over after placing most of the staves. Eyeball the back wall supports through the doorway to ensure that it looks level as well. 

  • Once the walls are level and freely standing I put three 3” screws through the staves and into the cradles to secure them in place. I didn’t do this at first and lost my level walls several times because they easily slide.

Step 9: Benches

• • I used remaining scraps of cedar from cutting the wall circles and scraps of the wall supports for the bench supports. Since this is only a four foot sauna I did not add a leg under the seats. 

  • Determine the height of your seats and draw a level line on both sides of the wall. Note that if your sauna is not level, you will need to match it’s level with the bench level. 

  • Screw in pieces of wall supports. 

  • Screw your cedar scraps together and ensure it fits snug over the wall supports. 

  • Add additional wall supports if they seem too thin/weak. 

  • Optional based on your support setup - Screw seats into the wall supports. Hide screws for smooth finish. 

Step 10: Heater

• • I went with the expensive Finlandia brand (linked above) and wattage based on what the barrel sauna manufacturers use. There are cheaper alternatives that I’m sure work just fine. A benefit of the Finlandia heater is it allows for water to be poured lightly over the rocks for steam versus some of the cheaper heaters that do not allow any water. It also is known to last longer and have better energy efficiency. 

  • Update 2023: email michael@sounart.com for discounted premium heaters and accessories!

Step 11: Accessories

• Update 2023: email michael@sounart.com for discounted premium heaters and accessories!

  • Lighting

    • I purchased a strand of copper-strand bead lights for under ten dollars at The Home Depot that worked out perfectly. You can see these hung on the wall in the video. Be careful not to use lights that will explode or melt. 

    • Anchor the outdoor-approved battery switch on the cradle next to the door then send the strand through the hole for the sauna heater.

    • More professional lighting options can be used and even connected to the sauna heater based on what you purchase. An electrician can get that sorted out. 

  • Thermometer

    • I purchased a cheap oven timer at Target after not finding any affordable sauna thermometers that I liked online. I noticed that after the first few weeks the temperature came down to more feel than reading the thermometer anyways. 

  • Timer

    • I usually just use my phone timer and lay it on the ground where it is cooler. You can also buy a sand timer made for saunas. 

  • Bonus: stretch bench

    • If you still have scraps after making benches then the quality cedar shouldn't go to waste. I made another bench that goes horizontal lying on top of both benches as a great way to stretch out your legs or lay down. 

  • Vents

    • Vents are recommended on the heater manual. I had enough air flow through the door and hole for the heater wiring that I did not cut air vents in the sauna. It is recommended to have some air flow in the sauna for comfort and heater efficiency. 

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