The perfect size outdoor sauna

Here’s a 3-D picture of a pretty good mobile sauna.


  • 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 over 100 saunas, and have sat in every one and have considered what’s good, bad and ugly with the design and construction of each sauna.

Some saunas are two man saunas, and don’t allow for a good sauna party.  Some saunas are bigger than a four man sauna and take too long to heat up, use too much wood, or the loyly (steam rising from tossing water on the rocks) never reaches you.  With divine proportion, according to the Greeks and confirmed by Da Vinci (thanks Matt), this is my ultimate sauna plan.

This design uses North American standard measurements, minimizing waste in construction and allowing for full cuts of material.  This design gives you a changing room, a critical space for privacy, having a beer between rounds, and a buffer for temperature extremes in cold climates.

TIP:  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!

EXTRA TIP:  * 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.

3/5/15 update to post:

The 3D drawing above may not be the best stove placement.  Thanks to Adam 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.

8x12 sauna plans

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76 thoughts on “The perfect size outdoor sauna”

  1. yea, i linked TO the ‘perfect size for a sauna’ post within a couple pages of my site (build your own, mobile sauna). gotcha.

  2. Rebecca:
    Bad news: Computer crash, lost the 3D file. Sorry!
    Good news: I have the complete building materials list. I can tell you that it’s a basic 8×12 ‘shed’ with a 5/12 roof pitch (or a roof pitch to match your house’s). Interior stud wall to allow for a 6’4″ wide sauna hot room. Want me to send that along? It’s an excel spreadsheet.

    Also, I have a basic blueprint, and can scan that sometime soon for electronic forwarding.

  3. Hi Glenn,

    Any chance of having the building materials list and blueprint? That would be great

  4. Alan…. Yes, i’m working on this! I have a building material’s list as well as blueprints.. coming soon!!! 8×12 is the key, in my book… but any questions you may have in the interim, please “fire” away.

  5. Thanks Glenn,

    8 x 12 would fit the room I have available in my smallish back yard perfectly. I love the idea of having the changing room also. I haven’t been able to locate any other plans/blueprints etc on the internet for other saunas but the size and shape of your design does appeal to me.


  6. Allen is on track and I have sent him extra doses of Nescafe coffee with instructions and he will dutifully report back to us on his project: building his own authentic Finnish sauna in his backyard. How are you doing on yours? Remember, we all need our own sauna haven, and if money is your setback, consider your own sauna as a permanent vacation, one dollar/kroner and one cedar tongue and groove board at a time!!

  7. I’ve been dreaming of having a sauna for years. Please send a copy of your plan and material list. Much appreciated!

  8. We’ve been searching how to build a sauna also.The plans and materials would be much appreciated.Thank you

  9. I can build the sauna no problem but what about a wood fired heater. What are some good sources and those that will help me keep the costs down?

    Are there plans for a home welded stove for example?

  10. Ken:
    One key material in building your own sauna: foil bubble wrap insulation.
    wood fired heater: There are imported ones from Finland, but to me, there is only one source you need to know for procuring a wood fired heater: http://www.lamppakuuma.com. Call Daryl, mention Glenn and saunatimes, he’s a great guy.
    With the Kuuma stove, you don’t need to weld your own stove. Once you see his product, you’ll see what I mean.
    Keep in touch.

  11. Just moved to northern michigan and have to build a sauna. Would love to get the materials list and blueprint for your “perfect sauna”. Looks like just the ticket. Thanks!

  12. Could I get the 3D file as well? Just downloaded the Google application so I can check it out. Thanks again. Great website!

  13. Hi, We’ve been looking for some design plans for our non-profit ski club here in southwestern Maine. We have the room to put one out side of our “chalet”, really a bunk house for skiers, we also have a wood stove that puts out a ton of heat that we don’t use much because of a negative drat in the cellar of the lodge. Is there a big issue with using a wood stove not designed for a sauna specifically. I think this one would work well because we could load it from the side or the front.. You thoughts??Also If you have a materials list for you superb looking sauna, I would like to get a copy.
    Thanks and best regards. Ed

  14. Well I guess I’m a dodunk for not following the thread. I found the list after posting my last comment.. Thanks!!

  15. Hi Ed. I can’t speak to your existing stove. If it works well, go for it, but I like an actual sauna stove for many reasons including drafting and wood burning efficiency. Glad you found my building material’s list for the 8×12 sauna. link here: http://www.saunatimes.com/2009/10/12/build-your-own-sauna-materials-list/
    Before you commit to building a sauna,, think about how many will be using the sauna. I wrote this post partly in jest, but there is something to the “sauna equation”, from this post:
    Nothing like a few sauna rounds after skiing. I like it tons better than a hot tub, no rodent killing chemicals and no alligator hide skin afterward.

  16. I’m second generation Finnish and grew up with wood burning saunas. Finally, planning to build one here in Maine. I would appreciate plans and materials help. Thanks

  17. You have a great website. Could you send me 3D Sauna Plan download? I have been in many saunas or what my wife from Russia call “banyas’ for quite a few years and they are awesome. We want to build our own now that we have our own place in the country. We live in Texas by the way. So, “howdy” from Texas. So, if I download Google Sketch up I can look at your 3 D Plan? Will I be able to use these palns to build our own? Thanks! Can’t wait for a reply. Darryl

  18. Hi Darryl:
    Bad News: I lost the Google sketch up file when my computer crashed.
    Good News: You don’t need it. Just build an 8×12 shed and frame an interior wall so you have a 6’x7’4″ interior room for the sauna. (your changing room will end up being about 5’x7’4″). Also, consider doing an ‘L’ bench vs. the dual bench, previously illustrated. I just built exactly this, and I’ll post pics. Glad you dig the website!! It warms me. PS.. $9k is about the price for what i’ve put into it.

  19. I think you would benefit from a Kuuma Stove. Daryl Lamppa is 3rd generation Finnish, and it will resonate well with you. I can’t believe how well it holds the heat in our MN cold.

  20. Found your blog by googling Philadelphia called sauna. Your 8×12 sauna has me thinking that may be the right size for a replacement sauna at my place UP on the Tundra. The 8×12 size is small enough that you don’t need a building permit as it is under 100 sq.ft.


  22. For the chimney you just give it 2x 90 degrees angles… Up out the stove, 90°, horizontal through wall, 90°, up past the roof. The horizontal part must have a up angle to allow the fumes to go UP the chimney. In our zone it’s 1/4″ for every 12 inches length. I put my stove in the center of the wall, and I built one L shape bench on one side, and one straight bench on the other. I also found a perfect size and cheap stove, it’s for temporary buildings (my sauna is a temporary building since it’s not on a cement patch) and it’s called the Hunter model, from Drolet in Canada. http://www.drolet.ca/en/products/wood/the-hunter-stove Good luck yall with your projects!

  23. So, I have to ask: is there a reason why your bench seating isn’t oriented in an L position, and is instead facing each other with the stove in between? I would think if your stove was located to the right of your entry door, you could fit a nice L shaped seating and have more distance from the stove and the closest lower bench, allowing more people to sit without getting burned up by the proximity to the stove. Thoughts?

  24. Hi Glenn,
    I’m interested in building a small 3 person steam room and sauna building outside with a dressing room on each side so I would build two seperate entrances one for the sauna and one for the steam room both being similar in size as your sauna room
    Can you send me the plans and material list to give me some ideas I will share my finished product with you.
    Thank you
    Sherry & Ron

  25. We’re looking at an 8 x 12 structure for our sauna. We’ve been debating if a change room is a necessity being that our Northern Ontario cottage is only 3 seasons. My thought process is we are building a sauna to sauna – why use half the building to store some towels when towel can be stored in the cottage and hangers on the exterior will do the trick – plus we’d be able to fit more people comfortably as we typically have friends/family at the cottage. What are some cons for building an 8 X 12 sauna? Will we use that much more wood?

  26. Glen: Regarding big(ger) sauna hot rooms, please read here: https://www.saunatimes.com/building-a-sauna/big-homes-big-cars-big-cheeseburgers-dont-build-big-saunas/.
    Regarding changing rooms, please read here: https://www.saunatimes.com/building-a-sauna/does-the-sauna-changing-room-need-a-new-name/. Though not a hard fast rule, even in three seasons, having a temperate zone from hot room to outside is most welcome (if not critical). If you build without a changing room, i’ll still come visit and we could have a great sauna, but there are these times when the cool down experience is best had in a zone at which the temperature can be controlled (hot room door open or outside door open for a few seconds). BONUS: If you EVER decide to visit your Northern Ontario cottage in the 4th season, you will be digging yourself beyond measure.

  27. Hello Glenn,
    I am a lucky builder of my one and only house.
    Instead of a fancy bathroom with a tub I will not use I put a sauna into the plans.
    The time arrived that I have to come up with the final details.
    As far as I understand rules and regulations I can only run it on electric.
    I decided on the Huum drop stove because I love the design and the logic behind
    the fact that a huge amount of hot stones might be as close to the deep warmth only wood provides.
    I just made my donation to your ebook and hope to find good enough instructions for my 6×7 shangrila.
    Also I would not mind any extra support/suggestions.
    Loeyly greetings

  28. Claudia: Your sauna and house project sounds fabulous. 6×7 can work fine, especially with the smaller electric stove. I really like the bench design detailed in the ebook, and nuances like a low bench that can slide and tuck under the upper bench for easy cleaning, etc. Consider “candle window” again, as detailed in the ebook. It’ll be awesome and keep in touch.

  29. Glenn:

    We just looked and and really liked your plans.

    1. What did you use for flooring? Did you insulate it? Is your sauna in Minneapolis?

    If you have plans, we’d love to have a copy. We live in Grand Marais and wonder if we should go with 2×6 walls. Any ideas on that?

  30. Hi Jerry:

    Flooring: 3/4″ subfloor, durarock then skim coated with drain. Insulate. Rigid 2″ between joist cavities but not critical.
    Minnesota: Yes, I built our sauna on Lake Vermilion and backyard in Minneapolis. Have built others in other places too.
    Plans: For sure, all is detailed in my ebook, Sauna Build from Start to Finnish. click over here —–>
    2×6 walls: not necessary. Actually, i’d suggest 2×4 as it’s crazy how losing 4″ inside dimensions is noticeable/missed. R13 in walls is perfectly fine. R19 minimum in ceiling and I suggest doubling insulation up top. Hope this helps, happy to help.. you’re on your way! g.

  31. Hi Glenn, fellow Sauna Society member Nick here. I’ve been pondering something. After your epic trip to Finland (and taking into account you can now build any structure 200 sq. ft. or less in Minneapolis without a building permit), would you modify the “ideal” sauna size at all from the 8×12?

    I’m planning to build this summer.


  32. Nick: Either way. Advantages of:
    7′: lower profile building, less boxy unit (preferred to the eye). Less material.
    8′: Able to get benches higher (relative to the height of sauna stove).

    7’6″ – could be the happy medium?

  33. Hello, bought your ebook and am soon embarking on this fun summer project. I plan on building a tiny sauna and change room on a 6.5’x10′ trailer. Any idea how heavy the load on the trailer might be? I see that the small kuuma is 375# and am concerned about total weight. Do you have a ballpark idea? Also, how would you line the outside of the floor for durability? Thank you!

  34. Yes, the Kuuma is a beast, but we put the sauna stove over the wheel axle, celebrating applying weight where it makes sense. Our 7×12 fish house mobile saunas are 2,500# with stove and stones, all in.

    We build our mobile saunas with aluminum framing. Then marine grade plywood sub floor.

  35. Are you selling & shipping stoves now or soon(ish)? I see that Kuuma is shut down for the time being. Your site couldn’t generate a freight quote to 97211. How do I get one? Thanks!

  36. Started using sauna at my gym about six months ago love it. Gym closed .Got you’re book last week started building today. Pier blocks in 3/4 minus ready for beams. Question should I use housewrap outside framing?
    4/12 shed roof Building 8×12 but making inside hot room 6’2 and taking from changing room. Doing two fixed high benches 6’2 with slide out dog eared 4′ below to stay clear of stove and not rake shin coming in through door.Putting an old wood patio door horizontal high as I can above wall mounted findlandia 800 watt stove.

  37. Housewrap: Yes. It will not trap moisture and you won’t get moisture between wall cavities anyway, as you’ll build it right (and follow details within Sauna Build Start to Finnish ebook.

  38. Hi Glenn,
    I bought your sauna e-book and have been reading all the articles on your site as I build my own indoor sauna. Thanks for all the helpful info! I have a weird unused space that used to be a stairwell leading from the basement bathroom of our rambler up to what used to be an in-ground swimming pool and is now our backyard. It has cinderblocks and storm cellar-type doors which I removed and roofed. (The first time I’ve ever done something like that! What a sense of accomplishment!) I’m now getting ready to frame the inside and insulate. My question is about the size. The unframed room is 4×6. I realize this is tiny but I’m on a budget and this space is available so it is what it is! I will also be using an “inauthentic” electric stove. hehe!
    The ceiling slopes away from the house and is 7 feet at the highest point and about 6.5 feet at the lowest. Anyways, I’m trying to figure out how to insulate in the thinnest way possible so I don’t lose too much space on the walls. I should be able to insulate the ceiling pretty heavily, but if I use 2x4s on the walls the room will shrink quite a bit! Any thoughts you have would be much appreciated.

  39. Can you make it fly with gluing and screwing 2×2’s to the exterior cement foundation, then 1 1/2″ rigid pink between the joist cavities? The 4×8 rigid cuts easily on a table saw, and you can tuck in between your 2×2’s. Then foil, then t&g. That’s how i’d roll!

  40. Thank you! Yes, I was thinking 2x2s as well, but wasn’t sure if insulation that size would be warm enough. Also read that the rigid foam insulation could melt or off gas chemicals due to the high heat? I’m guessing you haven’t had any problems with that or you wouldn’t suggest it. 🙂

  41. Hi Becky:

    Just as for every action, there’s an equal and opposite reaction, for every product, there is an equal and opposite freak out.

    I go to sleep at night reviewing the Johns Manville product sheets that detail service temp. to 250°f. As well as knowing that i’ve foiled and taped my seams well. Further, as we consider the heat variants in hot room, face of tongue and groove, back face of tongue and groove, face of foil, back face of foil, and the changing room temp of wall, temperature probing tells me that all is well.

  42. Thanks Glenn!
    It’s been fun reading your blog and seeing what an active sauna community there is in the Twin Cities. It’s a whole new world to me! I live in the just north of the cities and look forward to embracing this winter and doing some self-care during this stressful time via sauna! I appreciate your feedback. I’ll send some pics when I’m finished. Take Care.

  43. Hey Glen!

    Looks awesome! Would it still be possible for you to send me the plan and material list?
    I’m looking to make this kind of sauna at my home in Canada.


  44. The 8×12 building materials list are within the ebook Sauna Build Start to Finnish.. The spirit of the book is to allow for customization. The plans are not architectural renderings to be followed by a contractor, but more conceptual designs to allow for the sauna builder to advance their right brain thinking and customize elements for their own enjoyment/use/adaptation.

    I hope this helps you Ewan. 8×12 is an ideal sauna size (with changing room!) and you’ll see many examples of builds with this dimension sprinkled around this website. (guest posts of inspiration and celebration).

  45. Glenn,

    I am going to build an outdoor wood burning sauna on skids so it moveable but not really transportable.

    I spoke with Daryl about a stove and he encouraged me to build 8′ x 16′ x 8′ as opposed to 8′ x 12′ x 7′.
    Curious about your thoughts?

    Planning to deck floor joists with treated 1/2″ plywood, then flip it and attach to skids with angled structural screws, fill the cavities with eps foam and deck it with treated 3/4″ plywood.

    Interior walls will be lines with foil bubble wrap over rock wool. Do I still use house wrap on outside of framing? Is this type of detail covered in the ebook?

  46. I like what you’re thinking, and like the idea of house wrap, as it is a breathable product, and we only have access to our exterior plywood one time.

    Ebook should very much help you. The outdoor sauna is the sweet spot for the book.

    Regarding hot room ceiling. Dale at Lamppa Mfr. and I arm wrestle all the time about optimal hot room height. We should put the banter on YouTube. I’m a 7′ ceiling kind of guy, and Dale likes taller, higher. I am considering an internal stubborn old dog new tricks waiver form that maybe 7’6″ COULD be MAYBE slightly better than 7′ hot room ceiling, but the form is still on my desk.

  47. I have just bought a full spectrum infra red sauna.
    Each morning I use it for 10 minutes before breakfast.
    I never have stomach “noises”. But…
    During use, my stomach makes gurgling sounds.
    Does anyone know what is happening?
    Is this side effect safe?
    Thank you

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