Introduction: Finnish Sauna

Picture of Finnish Sauna

Growing up, I was always intrigued by saunas. I'm usually not one for extreme temps in either direction, but there's just something about a sauna that speaks to the soul. They're relaxing, cleansing, and a great way to soothe your body after a long day's work in the winter.

I probably never would have pursued this had it not been for my wife. In 2011, we met in Scotland, both attending the same grad school. She's 1/2 Lithuanian, and 1/2 Russian and grew up going to saunas with her family.

In Russia, it's a right of passage. Men and women visit gender specific saunas, and it's not uncommon to find a grandfather enjoying a "bath" with his son and grandson while passing down the family's secrets.

In Lithuania, families can rent private sauna villas for the day. You grab your key from reception, go to your private room that looks just as any other hotel door would, but enter into a luxurious suite with a small wading pool, hot tub, sauna, and dining room. My wife has told me stories about her childhood when her mom, dad and brother would go for the day, and rotate between the water and steam sauna, playing with dad in the water while mom relaxed with a smile. You'd think this would be pricey, considering how lavish it feels and how well the craftsmanship is throughout, but they're actually quite reasonable. Even today, the nicest of sauna suites can be rented for under 20 euros/hour. Often connected to luxury hotels, you can also enjoy room service without ever having to leave the comfort of the suite.

Let me just say that after my wife took me for my first Lithuanian sauna experience, I was hooked. When she asked me to build her a sauna after we purchased our new home, it didn't take a lot of arm twisting for me to agree...

I started the project in October of 2016, had it weather tight within a couple weeks, and then it was just weekends here and there until I had a week off during the winter, making significant progress. By early February, it was insulated and had power, and by late march it was usable.

Sauna's aren't a lot of fun in the summer, so it sat unused, but we had a comfortable and mild start to the summer so my weekends were spent finishing up the details, siding, stain, etc.

I still haven't applied the poly finish to the pine in the changing room, but I think it's ready for me to start putting together this blog. As fall sets in, we're using it more and more, and are loving it...

Step 1: The Joys of Planning...

Picture of The Joys of Planning...

Here's some pics of the initial building inspiration and the plans I sketched out.

I’m a bit OCD, so I tend to sweat the details. I probably spent over a hundred hours reading blogs, watching DIY videos, and shopping for specialty parts. I purchased most of the building supplies at the local big box store, the sauna equipment from a specialty supplier in NJ (West Sauna Bath), and a ton of detail stuff and tools from Amazon.

Along the way, here’s a brief summary of the key decisions that were made early on that shaped the project:

  • I would build a detached shed for the sauna. Our basement is unfinished (that's my winter project this year), and I considered putting it down there, but then I realized that I don't know what I don't know, and I don't know a lot! I was afraid I'd make a mistake, and would end up with moisture and mold infecting my house. Also, I like the detached "Finnish" sauna experience. It's my escape. Additionally, I designed and built it in a manner that if I ever start to question why in the world I built a sweat box in my backyard, I could convert it to a small studio office space.
  • The building would be roughly 8x12, divided into two 8x6 rooms: one for the sauna, and one as a changing room. These dimensions were very efficient and created very little waste. 6x8 is also a fairly large sauna. My wife and I are the only ones using it, but it could easily hold 6, so we have plenty of room to stretch out being just the two of us.
  • The sauna would be cedar lined, but I️ would not spend the money on clear cedar (except for the benches). Instead, I️ got the regular WP4 cedar tongue and groove boards to line the sauna room, but sourced them from a small town lumber yard nearby. The quality of their wood was far superior, and only about 15% more $$$ than the big box store. The size of my order allowed me to sort through it based on how clear (free of knots) each piece was. I️ ended up with several perfectly clear boards that I️ saved for the areas that would be a backrest and had plenty. In total, the cost of this cedar was about 1/3 of what it would have been shelling out for clear, and I have zero regrets.
  • The changing room would be pine car-siding. Cheap. Looks good. Got it from the big box store and just used premium grade 1x3 and 1x4 for all the trim and moldings. Has a modern cabin feel.
  • Electric over wood burning heater. At the end of the day, I wanted power to the building anyway, and while the thought of a wood burning stove was attractive in theory, I think I chose wisely when I considered all the additional work over the life of the sauna it would require for everything from getting the wood to cleaning all the ash that a wood stove would produce.
  • Definitely wanted steam capabilities, so I made sure to follow all the protocol for the damp environment: exhaust fan, the right heater & rocks, waterproof floor, aluminum faced insulation, with seams sealed using heat resistant aluminum tape.
  • Skid foundation - by far, the easiest foundation. Took 1/2 a day. No concrete. easy on the back, and structurally sound for a building this size. I did, however, opt for 6x6, even though all my research said 4x6 would have been plenty.

Step 2: Foundation

Picture of Foundation

This was easy. I cut out 2 parallel trenches, each 12" wide, and spaced so that my 6x6x12' skids would be exactly 8' apart from outside edge, to outside edge. dug the trenches down about 6 inches, filled with gravel, and compacted it all down. I now had a sturdy and level base to start from.

Step 3: Joists & Subfloor

Picture of Joists & Subfloor

I went with 2x8s for the joists and around the perimeter. Spaced 2' apart on center. I also grabbed some cheap 2x2s and made a border in each joist cavity, 2" recessed to accommodate a 2" piece of foam insulation board with an R10 insulation value. Cut each one 22.5" wide and glued them down snug into each opening. Secured everything to the skids with 4 galvanized elbow brackets & galvanized lag screws on each side.

Step 4: Framing, Window, Door & Metal Roof

Picture of Framing, Window, Door & Metal Roof

I pre-cut every piece of the framing the night before and marked them all based on which wall each was for, and marked them up for where everything fit together. I needed a buddy to help put the walls up, and this allowed me to maximize the time I had an extra set of hands when I needed them most.

I also shopped around and found a good deal on a door and window that had been returned to the big box store. Ultimately, I haggled them down to 75% off and got a steal. I needed these for the rough opening measurements.

I also decided to put in a transom window above the door. More on that later, but I love what I ended up with.

Sheathed with an aluminum faced OSB. The aluminum facing does not require house wrap/Tyvek, and also adds an additional R1 value of insulation as a thermal barrier. When you factor in the savings of no house wrap, I think I came out ahead with this choice. It also went up nicely.

For the roof, I chose metal, in bright red. It will last longer than shingles, installed much faster, and looks better. I didn't take many pictures on roofing day. Oops.

Step 5: Interior Framing & Insulation

Picture of Interior Framing & Insulation

Insulation is pretty important in a sauna, and you've got to be mindful of moisture. So I chose an aluminum faced mineral wool insulation for the sauna area, and aluminum faced fiberglass in the changing room.

As I framed up the dividing wall, I also needed to bring the ceiling of the sauna side down to about 7' and level. I just used 2x4's to frame it up, 16" on center so that I could add more insulation. This created a void between the sauna and the roof, so I went nuts with the insulation and just put any leftover scraps up there. I also insulated the ceiling bays with some pretty thick fiberglass rolls of R40.

Inside the sauna room, I sealed all the foil seams with a heat resistant, 3" foil tape. By the time I was done, it was practically air tight.

Step 6: Electrical Wiring & the Transom

Picture of Electrical Wiring & the Transom

I dug a trench about 2' deep in my yard to run a line from the house to the sauna. This is an area where I don't trust myself as much, so I hired a buddy who's a union electrician to run the big wires from the panel in my basement out to the building. He spent some time on the project, and only charged me a few hundred bucks for parts and materials.

He also helped me run all the high voltage lines for lights, outlets, and the power from sauna the control box (the brains) to the heater itself. It's good to have skilled friends!

Since I only had a few outlets and switches to install, I wasn't as worried about price, and wanted something that would really make a statement. Legrand makes a series of outlets and switches that are square, and have a cool and unique look to them, so I went with those.

At some point during the project, I went down the rabbit hole of research on low voltage LED lighting. It started because I wanted to run multi colored LED strips around the perimeter of the floor in the sauna itself. I ended up also creating a custom transom window, with a thermal pain on the outside, and a stained glass panel on the inside, with recessed LED light strips in between to make it glow. This turned out to be my favorite detail of the entire build.

The sauna controller has a connection for a fan, so I framed out an opening that would allow me to install an industrial grade fan inside the wall in the sauna to pull air from the sauna outside, and replace it with fresh air from the changing room by cracking the window. With the fan running, it's pulls all the moisture out in minutes, and with it off, but the vent open, it slowly recycles with fresh air to prevent it from becoming too musty. I framed the opening out in cedar, and bought a cedar vent cover from some place I found online. On both sides, I put up some stainless mesh to keep tiny critters out, and fingers from getting into the fan.

Around this time, I also realized that the 12kw heater I initially purchased was overkill, and I needed to down size to a 9kw. The folks at West Sauna Bath were really good to me, and made for an easy exchange.

I ended up with 3 outlets:

2 that are along the outer wall int he changing room. the third is actually burried inside an area I framed up between 2 studs on the back wall. This became my hiding place for all the LED controllers. There are 2 LED power supplies, one for the sauna lights, and another for the white LED inside the transom. I wired it up so that one plug of the outlet would be on/off at a switch on the wall for the transom, and also have a dimmer controller hiding in that cavity so I can control the brightness of the transom. The other plug of that outlet is "always hot" and powers the sauna LED lights which are controlled by a fancy looking LED touchpad controller I found on Amazon.

At about that same time, I was also running cat-6 cable throughout my house, and a friend has some direct burial cat-6 cable laying around. This allowed me to run an ethernet line from the sauna to the punch down panel I installed in the basement, and just buried it in the same trench as the power line. I might have the world's first Finnish Sauna with a hard wired Ethernet connection... Not sure what I'll ever do with it, but the thought was that I could add a wifi router from the sauna to cover the backyard if I ever need to, or if I ever convert it from a sauna building to a studio office, I'd already have the connection there.

Step 7: Interior Finishing

Picture of Interior Finishing

I sourced WP4 cedar boards from a local lumberyard for the sauna, saving the clearest pieces to go on the wall where it would be a backrest. The knots can get warm, so you want those where you won't lean onto them.

I used stainless steel brad nails for everything to prevent rust.

The changing room is all pine car siding from the big box store.

I installed an overhead light in the changing room, and an antique looking exterior light.

Between the sauna and changing room, I wanted to let some light in, so I went back to the local glass shop that made my transom window. I was shocked at how cheap they were ($23 for the transom), so I asked about a 40x40" thermal pane. It was only $60, and really opened up both spaces. Well worth it.

For the floor, I went with a vinyl click together waterproof flooring. it looks like wood, but is completely water proof. The floor of the sauna doesn't get very warm (heat rises!), so my only concern was moisture. It was cheap ($100 for a few boxes) and went in quickly and with ease.

Corner-round trim in the changing room to cover the gaps I left while learning how to install carsiding. Wasn't needed in the sauna, as I did that room last, and learned from my mistakes in the changing room.

Around the multi-colored LED in the sauna, I used the router to create some molding I could hide it behind. It's raised off the floor just enough that the light simply glows from the bottom of the walls.

Step 8: Benches & Interior Door

Picture of Benches & Interior Door

The benches are the only thing I used clear cedar for. It wasn't too pricey, and considering this is what I'll be sitting on, I wanted something that would be smooth and free of knots and splinters. I sanded the heck out of each 2x2" piece, and cut them down to slats.

I designed the benches to be removable, but attached cedar 2x4s horizontally to the studs with 4" stainless lag screws for support, while the benches themselves just ride on the rails and are held snug by neighboring pieces.

I'll see if I can get some better pics of this to show you how I built them, but each level is 2 removable pieces that make each "L", and they're sturdy as a rock.

I custom built my own door using a sheet of 3/4" plywood, and then lining each side with cedar & pine. I found some heavy duty stainless steel gate hinges, and called it a day.

Step 9: Siding

Picture of Siding

This is the part that I struggled with so much. Cedar siding is about double the price of other siding options. Even though this is a tiny little building, I still spent about $1,000 on cedar bevel siding. It hurt spending that much on such a small space, but I'm glad I did. Vinyl siding would have looked like crap compared to this. I also considered a cheaper material for the back (my neighbors see it, I don't), but I would always know it's there, and it would have bothered me.

Note - be sure to use Stainless steel nails for the siding. Anything else will leave stains as it streaks over time.

For the stain, I chose a translucent (NOT the same as semi-transparent) stain in cedar tone from Benjamin Moore Paints. It took two gallons and only required a single coat. I really like the translucent look, as it keeps all the grain detail.

Step 10: The Birds...

Picture of The Birds...

Around this time, my old pal James introduced me to his bird cam. It was a project he backed on kickstarter, and took amazing photos of birds. It's called the Bird Photo Booth 2.0. I started posting pics on social media, and got as many comments about the "sweet shed" in my backyard as I did about the critters, so I knew I was on to something.

I think I spent like $150 on the entire photo kit, total.

Worth it.

Step 11: The Finished Product...

Picture of The Finished Product...

I painted the door to match the roof, and added a coconut hair flower planter in the window. For this year, I built a small landing/step, but next spring I'm going to build a large deck on the front for a hot tub.

One of the outlets is at chest height in the changing room, and we added a little shelf for a place to put a radio, and a few sauna supplies.

We also put up birdhouses, using pulleys and a cleat on each side to make it easy to raise and lower them for cleaning and refilling. In the summer, we put up hummingbird feeders, and then some seed feeders in the winter to attract Cardinals.

If you have any questions, or need me to clarify anything, just leave a comment below and I'll do my best to answer them quickly!

Special thanks to:

  • My brother from another mother, Jerry, who loaned me his truck on several occasions for trips to the lumberyard.
  • James, who introduced me to the Bird Cam.
  • My buddy Matt who helped with the framing.
  • Dirk & Laura - My electrical gurus.
  • My wife - who was super supportive and let me use the sauna as an excuse to not do house chores.
  • My pops - who taught me the basics of building.


jrytlews (author)2017-11-16

That is a nice building! Glad I was able to help inspire a bit, love the upgrades!

BuzzHebert (author)2017-11-09


hornick007. (author)BuzzHebert2017-11-09

How this kind of heating works? Where the hearth for wood is located -outside sauna? how the stove is mounted?

I like this, but have no idea how to resolve wood heating...

BuzzHebert (author)hornick007.2017-11-13

My "heater" is an old propane tank that has been cut to 30" long and a door installed on the open end. A chimney hole cut into the top on the other end. The heater is placed through the sauna wall with the door that opens into a small room where I keep the wood and feed the fire. I filled in around the heater with pieces of block and mortar sealing the wall. I kept the header about 16" above the heater. I have had the sauna reach 110 degrees. Way too hot, but my kids wanted to see what temperatures they could take. Good luck and if you have more questions feel free to contact me.

hornick007. (author)BuzzHebert2017-11-14

Thank you, now its all clear! I found this type of construcion.

Harharikaur123 (author)2017-11-13

Awesome!!! Clever skilled you..and what a lovely story behind it including your wife’s childhood and the birdcam too!! Amazing.

bethmwl (author)2017-11-13

Loving it! The transom window is beautiful.

super_me (author)2017-11-12

it's really really nice...if I had space I wld like to build it, or at least like just a studio or office like u sed

sgbotsford (author)2017-11-11

Caveats: Vinyl plank flooring is not waterproof. Itself, it won't be harmed by water, but small amounts of water seem to get through the joints. This may not be apparent at first, but vinyl shrinks as it ages, and pinholes open up at joints, especially corners. Plan a way for water to escape. In general the extreme humidity in the sauna, along with the high temperature gradients require careful detailing of the vapour barrier.

You may want to install a humidity sensing exhaust fan that pulls air out of the sauna after use until the humidity drops to local ambient. This can take several hours, so a timer may not be sufficient.

In our jurisdiction, underground wire has to be 30" under grade. There is a provision for less, but then you have to put a pressure treated 2x6 over it. We also have problems with pocket gophers. I now install all buried lines in pipe.

For others: There is no necessity to use cedar, although it's resistance to decay may be desireable. For that purpose redwood will also work, and in some areas will be cheaper. I don't see any reason that fir or spruce couldn't be used, although you will want to check for pitch pockets as well as comfortable seating. Larch isn't commonly found, but would be excellent in a sauna. Nor does it have to be conifer wood. If your local re-use store has a batch of surplus hardwood flooring on for cheap, go for it.

BillyStuart (author)sgbotsford2017-11-11

The high voltage lines (one 20amp, and one 50amp breaker) are in pipe. Our local code call for 30” minimum for direct burial and 12” for in pipe. The direct burial cat6 is not in the pipe, but is in the same trench, separated enough to prevent EMI.

The Shaw LVT I used features their newer Floorte LifeGuard waterproof core tech and is pretty solid. Guaranteed waterproof for 25 years. It’s the flooring they recommend for flood plains, so I’m pretty sure the few drops that make it through the heater will be just fine. The subfloor is AdvanTech sheathing, lifetime garaunteed to prevent swelling. I saw a stress test where they threw a sheet in a pond, retrieved it a week later, and it was still perfectly flat and free of swelling. Again, pretty sure it could hand a few drops if they somehow managed to seep through a 25 year garaunteed waterproof floor, and then past the water and vapor barrier, and then on the sheathing. Doubt it ever gets there, but if it does, I have no worries.

Several woods can be used. In my area cedar was both economical and I preferred the aroma cedar leaves behind for several years.

My hygrometer reads back to ambient humidity after about 20 minutes after I turn it on after I’m done. Do you know what it would cost to put in a humidity sensing automatic exhaust fan?

I love how everyone point out what they believe are all the things I didn’t research. I invested well over 100 hours of research and consulted friends who are architects, electricians, and flooring specialists.

I’m sure it’s not perfect. It’s a DIY project that requires a ton of learning along the way... I’m happy to address why i made each decision. Some were done for sheer economics and others based on tech advances that eliminated old concerns.

TinyT2 (author)2017-11-10

It is also to aid the air circulation. The air rises at the heater, follows the wall upwards to the ceiling, over to the other wall where it goes down to the floor again. Then along the floor to the wall where the heater is. This way the air spirales its way through the room until it reaches the outlet as far from the inlet as possible. This means that the heat will fill te entire room more evenly. Horizontal panels will cause turbulence by the walls and the circultion will not be as effective as with vertical panels.
This is also why the inlet and the outlet should be placed as far from eachother as possible, and reach the same outside room. If the inlet and outlet are placed on opposite walls, the flow will be disturbed by the wind outside. If the wind comes from the heater side, the air will not be heated as it will blow past the heater too quick. If the wind comes from the outlet side, the circulation will be reversed and heat will blow out through the vent below the heater.
There is no risk for moisure in the walls as a sauna is much dryer than an ordinary room, also when you pour a lot of water on the heater when using it. After use, it will dry out by itself and no moisture will stay in the walls.

TinyT2 (author)2017-11-09

A few comments from a sauna-builder in Sweden.

The sauna room should have vertical panel.

The sauna room should not have vents to the outside. Air in (below the heater) and air out (high and as far from the inlet as possible) should lead from the same place, e.g. the changing room. From there a vent should lead to the outside.

You should use e.g. Abachii-wood to sit on (much nicer as it does not get hot).

SciFiJim (author)TinyT22017-11-09

What is the reason for vertical panels vs horizontal panels?

BillyStuart (author)SciFiJim2017-11-09

It’s supposed to be for water running down, with the grain. I looked into it, and found that’s a tradition stemming from before tongue and groove boards and isn’t necessary. I chose horizontal because: a. with tongue and groove, water won’t run between the boards, so while his advice is traditional, it’s not critical. And b. the cost of a 6’ board verses an 8’ board was actually significant. With vertical, I would have had to purchase all 8’ boards and cut them down wasting several 1’ sections. I was able to get away with mostly 6’ pieces with very little waste on 3 sides (including side with door) and the ceiling. Only needed 8’ for the back wall.

B_Frank (author)2017-11-09

Brilliant design! Extremely eye-catching and seems ultra functional as well. It is always intriguing to me to see how many commenters tell you exactly how things SHOULD have been done instead of appreciating the way you HAVE ALREADY DONE them. So goes online forums I guess. I was curious exactly what brand and model of waterproof flooring you went with? Have you had any problems with expansion or contraction of the flooring? I am evaluating options for a similar project and would love a review of the planks that you used. Thanks for sharing!

BillyStuart (author)B_Frank2017-11-09

I went with a luxury vinyl tile by Shaw. Being vinyl, there is no expansion/contraction and it’s waterproof. Super easy to install. It just all clicks together and goes down quickly. At first I worried about it melting or having heat problems, but now realize that the floor never gets anywhere near a high temp, and has turned out to be a great option.

B_Frank (author)BillyStuart2017-11-09

That's a great referral. Thank you! And don't let the crap get you down. Looks great.

BillyStuart (author)B_Frank2017-11-09

And thank you. It’s disheartening when people sh*t on your finished product, but yeah, such is online life. Everyone’s a critic, but few are willing to dive in themselves.

Pigmom (author)2017-11-09

Really awesome. Wondering about permits if needed could this go as a storage shed or did it have special requirements. Yes I do know this is different fron state to state and even local codes. I’m thinking I wouldn’t need one because of the size of the building itself.

BillyStuart (author)Pigmom2017-11-09

In our local municipality, a building permit (and inspections) are require for anything larger than 100 sq ft. 8x12=96sq ft, so I needed no permission or any sort of permit. :)

oh3we1 (author)2017-11-09

As a Finn I think I know a little bit about saunas. So I wonder do you just sit there without throwing any water over the stones to get steam in the sauna?

The idea of "saunaing" is to get oneself sweating all over by getting water vapour in the room. If you just sit there and get yourself a warm feeling it has nothing to do with real sauna.

After the sweating period (10 mins) you go out, swim or take a cool shower and come back. Over and over again. Don't forget to hydrate yourself with cold beer or mineral water. :)

PS. The 12 kW sauna stove, "kiuas" is really too big. The hot feeling should appear by generating steam as I told earlier.

Have a nice "löyly" ( hot steam) in your sauna.

RebecaD3 (author)oh3we12017-11-09

hello , I have been as an exchange in finland and i loved the experience in saunas over there, still miss a good time in sauna

BillyStuart (author)oh3we12017-11-09

Ah... You bring up something I learned the hard way. Yes, 12kW was WAY too big... i ended up returning the 12kW for a 9kW, which was still a bit big, but works just fine. 6kW would have probably been sufficient. I did opt for a lower end heater (made in china), as my budget was getting a little crazy. But I made sure to leave myself plenty of extra wire in the walls and a simple method to fish through that part of the wall. I expect my "made in china" heater will end up giving out eventually, and then I'll replace it with a higher end product from your part of the world. As a Finn, you most certainly know a thing or two about saunas, and I wish I could have afforded a higher end heater from the get go.

In my first step and on the plans, I ended up with some adjustments from what is posted in the pics. First, the heater was downsized to a 9kw. Second - the sauna controller was moved to the back wall so I can easily fish wires from the control panel to the control box when I eventually swap it out for a Scandinavian heater. Third, I moved the dividing wall back a bit to add about 6" more space to the changing room.

As for steam, yes, we have a sauna bucket and ladle, which you can see in the final step's pictures. The stones heat up, we spoon water on, and it gets nice and steamy inside. When we're done, we kick on the fan and open the vent all the way, and it pulls out all the moisture.

JariL2 (author)2017-11-09

Looks very nice! Few toughts tough. Did You leave any gap under the wallpanels? There needs to be about 1" gap behind them to keep structures dry. And the wallpanels start from about 4" off the floor. The sauna door needs about 8" gap under for fresh air. Good "saunatimes"!

BillyStuart (author)JariL22017-11-09

Not sure what you mean by a gap under the wall panels. As I built the door, there is a 2.5" gap under the sauna door to allow fresh air to circulate in. The wall vent to the outside is opposite the door, and about 36" up from the floor. It also has a fan inside the vent that is controlled by the sauna controller. With the fan on, it pull out all the moisture in a matter of minutes. With the fan off, but the vent open, and the window in the changing room cracked, it slowly pulls fresh air under the door (which is next to the heater, and convection properties allow the fresh air to heat up, rise, and then come back down and out the vent. here's a pic with a basic explaination of how that works.

JariL2 (author)BillyStuart2017-11-09

I mean like on this page...

On Finnish saunas there always is a "space" between wall panells and insulation/aluminium foil because of the "point of moisturation" that occures especially on cold weather when moisture turns to water on any cold enough surfaces.

BillyStuart (author)JariL22017-11-09

Ah, now I understand what you meant. Yes, I cut down some cedar 2x4 (inches) into slats that are 1-1.5 cm thick, and attached those to the 3 exterior walls and ceiling (not the wall between the sauna and changing room, even though I probably should have) after putting up the insulation, but behind the cedar. I also left a small (maybe 1cm?) gap at the floor to allow air to circulate. That's part of why I did the LED lighting around the floor the way I did, so that it covers up this gap nicely.

We plan to stay in this house for about 5-7 years, and our next home will be our "forever" home. I learned from a lot of my mistakes on this one, so when I build the next one, I'll have a much easier time. I still wonder if I made the right call going with electric vs. wood, but we're in a residential area, and I don't have any forest to go cut my own wood from, and didn't want the hassle or expense of constantly sourcing/hauling/splitting it.

allenwilson (author)2017-11-09

Excellent Instructable! Thank you for the detailed plan and information sharing. Can you provide the total project cost? Also, is the heat from the sauna sufficient for heating the changing room? In areas with cold seasons, that would be important. BTW, pics of the metal roof would be nice!

BillyStuart (author)allenwilson2017-11-09

HI, Allen. Sorry about the roof pics. I was so focused on getting it done that day, that I forgot to take any photos. Next time I get the ladder out, I'll climb up there and take some detail shots.

The heater does warm up the changing room quite well. Last winter, the heater was connected and running by February, and I used it to heat the space while I built the benches and finished all the details. It was below 0 on several occasions, and I was actually working in my boxers and a t-shirt after a while, despite it being so cold outside. We're in Central Illinois, so we get 4 proper seasons. Hot summer, cold winters.

What I have been doing this fall, is propping the door open (just an inch or two) during the +/-20 mins of preheating, and the changing room is warm while the sauna gets pretty darn hot.

I started with a 12kW heater, and returned it before I ever hooked it up, as it was extreme overkill. The 9kW I ended up with is still larger than would be needed for a 6x8x7 sauna. I think a 6kW would have been plenty, but I wanted it pretty powerful simply for the changing room to warm up too. My wife likes the sauna extremely hot (she gets it above 200 degrees f, but I prefer it around 175-180).

While I saved most of my receipts, I have not added them up. I'm almost afraid to, as this project was originally supposed to be a reclaimed pallet wood project with a DIY wood burning stove. But I got into it, changed the entire scope, and went a little nuts. When I first drew up the plans for reclaimed pallet wood and a DIY wood stove with my wife, it was supposed to be less than $800, but I pulled the old bait n' switch on her. ;)

I think the basic structure was about $1,800 for skids, framing, roof, and insulation. Another $200 for flooring, $1,000 for siding, $600 for the heater & stones, $1,000 for the cedar wood on the inside, and $350 for the pine. I spent about $350 on my electrical contractor (he was a friend and cut me a good deal) and another $500 in various electrical parts. The little detail things add up, and I'm sure that's at least another $500-1,000. If I had to ballpark it, I would say I spent between $6-8K in hard cost, and hundreds of hours of research and labor (but I really enjoy both). I need to scan in all the receipts and dig through my emails for everythingI ordered online. At some point this winter, I'll assemble all that and edit the post.

I only needed a second set of hands on framing day, and on the siding. Everything else (except for the electrical) I did solo.

smontilla (author)2017-11-09

Great instructable and what a beautiful end product! Thanks for all of the descriptive details in the narrative. It looks like you do great work!

jltjr (author)2017-11-09

Great Instructable project.

snoop911 (author)2017-11-09

Do you have any thoughts on any pre-fab sauna kits? Most seem to be electric/infrared (Health Mate), but some offer gas (Finnleo, Scandia etc).

I'd love to go gas gas/fire since electric saunas seem to take longer to heat up, and don't get nearly as hot.. plus I rather pay the higher installation cost rather than the higher operating cost.

A tiny closet-size gas indoor sauna in the garage would be ideal, with vent plumbing to the outside, but not sure if it's considered safe (or if it's even permitted in my area). Any idea if it's do-able?

BillyStuart (author)snoop9112017-11-09

I looked at some prefab kits when I was doing my initial research. Ultimately, I decided to build my own. This saved a bunch of money compared to the prefab units, and I was able to build it just how I wanted it. All other things being equal, I would have preferred a gas heater, but the costs got out of control when I started adding it up. It's certainly doable to build out a sauna into pretty much any area, including your garage, but you'll have to be mindful of the venting.

BillyStuart (author)BillyStuart2017-11-09

I have a 9kw heater, and it gets up to temp in about 20 minutes. It also gets pretty hot (190+ F, at the ceiling). This is plenty warm, and i've never felt like it wasn't hot enough. I set it to about 175, and find that to be about perfect for my preference.

elotromaddog (author)2017-11-09

wow, your sauna looks so cool. I do hope that you keep up the good work.

congratulations on your project

Vesa Seppänen (author)2017-11-09

For increased efficiency, place the stove under the benches.

- Perkele

Haha! Perkele!

Copymutt (author)2017-11-09

with the heater under the bench you're gonna cook somebody's butt. I don't recommend that. As a side note, never use any finish, sealer, preservative on the interior walls. Been taking saunas for over 20 years. During this part of my life I've never had even a cold.


Augustny (author)2017-11-09

Very nice!

Tuomas Soikkeli (author)2017-11-07

Very interesting project.

One usually used option here in finland is to make floor from spruce ( or impregnated wood) boards and leave 1cm cap between them, so water drops through the floor to the ground. (thick layer of crushed stone) Foundation is lifted to 30 cm or above in that case, to ventilate it.

Mostly used option is to make floor from congrete and tiles.

Very nice sauna, enjoy it.

Thanks, Tuomas! If a Finn likes it, I know I've done something right! I considered pouring a concrete slab, tiling the entire thing, and then putting down duckboard (I think that's similar to the wooden slats that you described), but the concrete work was just too overwhelming, and would have require both equipment and skills that I'm lacking...

deluges (author)Tuomas Soikkeli2017-11-08

Nice tip! I might use it... Just for the kicks of making somtehing out of the ordinary here

deluges (author)2017-11-08

Very nice work.

I am working on a sauna too and those are great ideas for the interior. I favorited it for future reference.

seamster (author)2017-11-07

This is top-notch work, all around. Very inspiring!

That stained glass window, did you make that too?

BillyStuart (author)seamster2017-11-07

I wish, but I don’t have that level of skill. I actually found it for pretty cheap on wayfair. It was originally meant to hang in a window on a chain. I used a handheld grinder and gently got rid of the metal welds/hanging brackets to make it perfectly rectangular.

I sourced this before I ever started building and designed the entire transom around it, including the custom thermal glass panes. I think the stained glass was around $65, and the thermal pane was less than $25 at a local glass shop. Took them about 2 days from order till pickup.

jbodanieljr (author)2017-11-07

Great job!

Swansong (author)2017-11-07

Fantastic job! This looks really nice :) It would be great to have one of these in the winter when it gets really cold!

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