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Let’s talk about sauna ceiling height, bench height, venting along sauna door down to the inch (and centimeter)

I thought I was building and advising to build saunas correctly. And for the most part, I am. However, there is one WIDE difference on what many are doing in the US compared to Finland:

Gap along the hot room door.

Finns, the pros, are nuts about fresh air and venting. With a wood fired sauna stove, this is critical yet not AS critical as with an electric stove.

Why?

Wood stoves draw air and help circulate air on their own.

But electric stoves suck, in terms of air flow and ventilation. We need to be cognizant of good venting!!

Why?

Fresh air and oxygen circulation allow us to enjoy our time in the hot room. Dizziness from time spent in a sauna is more apt to be from a lack of oxygen than too much heat. How do I know this to be true? I took 50 saunas in 12 days in Finland, and I was never dizzy.

Oxygen. Air flow.

How do we design our saunas for optimal oxygen and air flow?

IMPORTANT CHARACTERISTICS:

  1. 42″ (107cm) Top bench to ceiling. When sitting on the upper bench, we want to be able to put two fists over the top of our head to the ceiling.
  2. 18″ (46cm) lower bench. This is optimal chair height and comfortable for most adults (no scrunching or feet dangling).
  3. 6″ (15cm) raised floor deck. This step up, when entering the hot room, keeps the feet warm when sitting on the lower bench as we have an air gap from the actual hot room floor to where you sit, stand, or walk.
  4. 4″ (10cm) gap along hot room door. This makes the Finns happy. Plenty of air flow.
  5. Vent: opposite wall as stove, eye height while standing. A few inches (10cm) down from the ceiling.

What’s wrong with this design?

I know, I know, while sitting on the upper bench, our feet, resting on the lower bench, are a few inches below the sauna rocks.

If we build saunas with 7’6″ (229cm), we can move everything up 6″ (15cm). This way, while sitting on the upper bench, our feet are at or above the sauna rocks. But this creates a new problem. Now we have 12″ step up from changing room floor to hot room floor. Two steps, 6″ (15cm) each can be quite clunky and cumbersome. Worse, these steps can be dangerous for children or senior adults as they navigate themselves off from the top bench, down steps and out to the lake or cold plunge water feature.

Let’s pick our poison

While sitting on the upper bench, do we want our feet a few inches below the sauna rocks, or do we want 12″ of up and down steps each time we enter and exit our sauna hot rooms? Many (including me) choose to have feet a bit below the sauna rocks and one less step coming and going, over and over.

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29 Comments on This Post

  1. The answer might be a small step at the bottom. Most of our lower bench heights (where our feet rest) here in the U.S. are way too low according to the “law of löyly”. 7’6″ vs. 7’0″ might be the answer and the “right height” for a sauna. Top bench height would be about 48″ when building with a 7’6″ ceiling. A major problem for us here in the U.S. is that, our favorite stove, (Kuuma) is 33″ tall. That only leaves 15″ drop from the top bench (33″ height for bottom bench). That is a big climb and not a lot of drop from the top bench.

  2. Glenn thanks for this update! I will definitely be changing my drawings for my up coming build.

    I am considering curving the ceiling. 7′ height along the long walls and 7″-6″ along the middle (barrel curve). I feel this will help loyly roll up off the stove and curl across the ceiling more naturally. Your thoughts?

  3. Exactly Jeff!

    With a taller stove, we’ll be building saunas that’ll be like navigating the bleachers at a high school football game. Each step comes with a potential trip and fall (and heckle from the peanut gallery).

  4. Steve: The gambrel ceiling in hot room is a good concept. As you mention, it helps roll the Loyly, and technically it does “de mass” the hot room area a couple few cubic feet.

    You’ll want to make sure your head doesn’t bump into the slope, of course.

    And I built a really great sauna once with a soft pitched ceiling, higher towards the bench side. However, every iteration or alteration comes with an equal and opposite concern. In this case, height from stove to ceiling was an issue. And the Loyly police could take issue with how the steam may settle in the upper triangle formed from a shed slope ceiling.

    And one more thing, Saunaseura (Finnish Sauna Society) #5 is nicknamed “The church” because of its gambrel roof design. So, if they are doing it, i’m sure it is orthodoxically approved by the sauna evangelists.

  5. Hi Glenn
    I have noticed I get a bit light headed. As you may remember I have the Kuuma stove and a 1″ gap under the door and a separate combustion air intake into the hot room. I could remove another 1″ from the bottom of the door and raise the height of the duck board by another 3/4″ without needing to move my benches higher. Do you think it would be worth the effort?
    Cheers
    Ceri

  6. Hi Ceri:

    Tough call. A Finlander would say, cut the door. Maybe try Running your sauna as normal, then one round, open the door with the slightest crack/opening. Run your hand along the door, with the slight opening from below and all the way up the door and see if you’re getting air flow coming in. Maybe get a candle even and identify air flow/pressurization. This may tell you whether your hot room wants more venting (intake).

  7. Instead of steps, consider building a ramp down into the dressing room with a non slip surface.

  8. Thanks for this Glenn.

    I think our final elevations are:
    Ceiling: 96″
    Upper Bench: 52″
    Lower Bench: 34″
    Base Platform: 17″
    Steps: Three 6.3″ steps from changing floor to base platform.

    Stove is a Himalaya so taller than most. Top of the rocks is about 41″ so feet will still be about 7″ below the top but hopefully not too huge of a temp differential.

    We’re changing the door gap to 3″ from the standard 1″ that our supplier does. We’ll see how it works and can cut off more if necessary. They were going to place the exhaust vent on the same wall as the door and heater but we’re having them move it to the opposite wall.

    Question: Should the vent go to the outside or is an adjacent room OK? We’ve a conservatory above our sauna and I’m toying with running the vent in to there.

  9. Walker:

    Good one. I am not sure if a sauna builder in Finland (or one with multiple of the same consonants next to each other in their last name, ie. an ancestor from Finland) would advise against “vent to the outside” but truth be told, I did exactly what you are thinking with my backyard sauna. The upper vent feeds into our den/lounge above the hot room.

    While sitting upstairs between sauna rounds, our feet have been able to benefit from the principle of convective heat transfer (heat rises). Our hot room is benefiting from good air flow. Intake: fresh air via a vent a couple inches above the floor and the generous gap along the hot room door.

    So, we’ll see if any readers with last names like Hankkannen or Heikkinen advise against an upper vent not to the outside, but i’m cool with this adaptation for “recycling” our heat.

  10. Hi Glenn. I’m about to build out an 8′ by 12′ shed very close to your ebook plan. My shed has 8 foot side walls so I actually have 92″ to work with and will go as high as possible. I was planning on a 4″ door gap… But now musing with the idea of floating my entire center wall by 2″. Any thoughts?

  11. Matt: Best gig is to gap your hot room door, as you mention, and build common wall per usual. That’s plenty of intake venting. As you plan your benches,I suggest working from the edges: As you sit on the upper bench, two fists above your head to the ceiling, and as you stand on the floor, consider duck board or a raised step, giving a reasonable step down from hot room to cool down room.

    7’6″ is a great ceiling height, for all this to work, as detailed above.

    The Finnish police may issue a frown if, as you sit on the upper bench, your feet are at a height below the sauna stove rocks, but we have to balance this against the vertigo of that extra step or two within a smaller footprint home sauna to get up that high.

  12. Good morning,

    I recently ordered your book on building saunas. And I was able to download the eBook, but the problem is there were no photos with it and the link that was attached was unopenable. Could you please advise on how I will be able to download the photos? They will help me a lot with my build.

    Thank you for your help

    Troy Gregg

  13. Glenn,
    I’ve been trying to listen again to the pod from Finland where you discussed the 8’ ceiling… I thought it was with either Jarmo or Risto but I must be mistaken. Can you direct me to the proper episode? I’m very interested in the higher ceiling concept if I can figure out safe steps…

  14. Sorry Glenn! Just found my post where I asked the same thing a couple weeks ago! My 54 year old brain is getting the best of me!

  15. Glenn: I am still designing my sauna space, so this is a timely discussion. A couple Qs, one of which is unrelated to this string:

    Q When you refer to a four inch vent “along the sauna door” do you mean the 4″ vent is built into the bottom of the door, say a 4″ x 10″ built 3″ up from the bottom of the door? Or are you referring to a door substantially shorter than the jamb?

    Also, I have seen other designs which locate the lower vent in the wall, directly under the electric sauna heater. Which location is better, in your opinion?

    Q. I am building a 4’6″ x 5′ sauna, so I will need lots of 5′ boards. I have located a source of clear cedar T&G, and they have tons of 5 foot long, 1 x 5 boards, and they are priced reasonably because (I assume), 1×5 is not too common, and nobody wants just 5′ boards. The reveal is 4 1/4″ and the thickness is 19/32″. My question: will these boards tend to warp, given the width and thickness? I am not sure if the grain is flat or not; will that affect your answer?

    THANK YOU!!
    Don

  16. Hi Don.

    1. door 4″ shorter than the jam. Simple opening along the bottom.. you got it.
    2. cedar won’t warp. you’ll be good!

  17. Hi Glenn,

    Thank you for your response last month. Still loving your role in the sauna universe!

    I think I have collected a couple questions and distilled my thoughts. I now have my external structure built (mostly). After percolating on your suggestions and content for months, I worked myself up to a bigger building to really allow for a quality changing/cool-down space that will serve as a hangout for my family and friends. With the help of a super-skilled craftsman friend this weekend, we put up a 9’x16’ building made of 2×6 framing. Meaning I have plenty of space inside for an “ideal” hot room with my desired measurements including ceiling height. Which brings me to my questions:

    1. Accounting for what I think of as your recent “Finnish Directive”, I was thinking a 7’6” hot room ceiling height allowing for the raised floor and therefore higher benches in relation to the top of my heater. (I’m going electric, possibly a Tylo 8kw heater.) Is 7’6” from actual floor to ceiling paneling the way to go? The heater is only 26” tall before a recommended mounting 7” off ground, so 33” to top). Would you still recommend getting the bonus height with a false floor and the 7’6” room?

    2. The width across the back wall will be just shy of 8’ once I get the cedar paneling in. Here’s my big ponder: Where to put common wall? 7’ so I have 7x8x7.5? Or maybe 6.5” deep so I don’t let the volume balloon out? The heater I was looking at is rated up to 440 cubic feet, but I don’t want to build too big. I have tried to take to heart your cautions about going too big in the hot room. Picking the ideal dimensions up front is what keeps me up at night…..

    3. This is really a part B of the previous question, but if I do an A+ job insulating with high R-value in my 2×6 walls and especially the hot room ceiling, I ought to be able to get the hot room heat cranking even if I’m around 400 square feet, right? I’m in Oregon, so outside temp will seldom be below 30 even in winter.

    As you can see, I’m heavy into the over-thinking phase right now.

    Super appreciate what you do, Glenn! I will probably be back at you for more expertise as I get this thing finished on the inside.

    Chris

  18. An electical back-up generator will be required if the power is ever disrupted during a sauna session.
    Just sayin..ya know.

  19. Chris: It’s ok to be in the over-thinking phase. Sauna building isn’t like building a deck, where anyone at any lumber yard can point you in the direction of joist hangers and deck screws. Thanks for numbering your questions and let me try my best:

    1. HOT ROOM HEIGHT:
    This 7’6″ has thrown me for a bit of a loop as well. I’ve always built and enjoyed 7′ ceilings for many reasons, primarily in that once we step down from the bench, stand on the hot room floor, we are on one level: hot room, changing room, outside deck, etc. I like one level living. I like hosting saunas with one level living (especially in the day when we had many party saunas with lots of coming and goings). But the “feet at level of sauna rocks when sitting on the bench” seems to be as important in Finland as coaches telling forwards to back check. So, this is what prompted the drawing and post above. I don’t have an exact answer for you, but what I would probably do is settle on your stove, get your stove and measure height from floor to your rocks, and set your low bench there (albeit virtually). Then work up and down from there. This way, if you end up taking a sauna with a Finnish hockey coach, he won’t blow the whistle on you.

    2. COMMON WALL: I can suggest what to do, but I find the best thing is as follows: make a cardboard template of your stove footprint and “mock up” your common wall location (use a 2×4 cut to length, which will end up being your bottom plate). I have done exactly this and have never regretted taking ownership to this important decision on site (not on graph paper). Feel your hot room. Feel your changing room. Nudge the 2×4 until you have it exactly how you want the two rooms sized. Once defined, pencil mark your 2×4 and build your common wall. Guarantee: when you’re done and taking a sauna, you will remember this tip, and will be glad you did it.

    3. INSULATION/HOT ROOM CRANKING:
    Please search “electric sauna stoves” on this website. Jeff guest posts. Jeff is the most knowledgeable, objective electric sauna stove expert in the US NOT in the sauna stove selling business. Hands down. We are lucky to have him as an advisor on saunatimes. I am pretty sure once you read his guest posts, you will have your answer. As far as insulation goes, R19 with foil is totally more than enough, even in Alaska (and Northern Minnesota, where my sauna walls are 2×4 with R13).

    Good questions, and glad you shared on here so others down the same path can hopefully benefit (and chime in where/when desired).

  20. Glenn,
    I have a question about waterproofing under the wood stove. I have your e book and am going to use the paving stones like you suggest. Do they sit directly on the plywood or do you need some sort of waterproofing underneath?

  21. Hi Mike: I glue the paver stones directly to subfloor. Then skim coat everything with vinyl cement. This has worked great for me for many builds over many years. Good luck, keep it up!

  22. Glen-

    QQs on venting and house wrap. I am having a shed build by Tuff Shed and plan to finish it out myself. The questions that I have for you are…

    Do I need to put a vent in the attic if I am using house wrap, and foil wrapping the lower room? The shed will have a metal roof, if that matters.

    Also, the question came up from the builder as to whether I want/needed to house wrap it, and there seems to be some zoning concerns where I am at in Chanhassen, but from what I have read, it seems advisable.

    Kindly let me know your thoughts.

    Brent

  23. I like a vent in the hot room to the outside and yes, a vent in x room is good too.

    Keep it up Brent. The Sauna Talk episode with Steve is a good one (building a sauna from a shed).

  24. i would recommend the house wrap, not sure why that would be a zoning issue? maybe some type of building code issue but i can’t see why zoning would care. as for the vent, i believe you are asking about a vent in the attic to the exterior, like a ridge vent on the rooftop or a gable vent on the side. this is also advised, helps vent heat/moisture from that area. if it is simply enclosed, you run the risk of mold or similar developing in there. to function properly, you really need soffit vents as well to establish good airflow.

    you definitely don’t want to vent the hot room into the attic, even if you have an attic vent to the exterior. even venting from the changing room to the attic is not a good idea.

  25. Regarding the “feet above the stove” rule; what about a foot rest? I’ve been in a few saunas over the years with a comfortable foot rest/stove guard made with an angled board that is very comfortable and warms up your feet nicely after a dip in a cold lake.

  26. Erik: Totally. The foot rest has fallen a bit away from use over the past couple decades. Old school functional saunas (those dotted along shores of crisp cool lakes, and by rural farms and fields in rural hinterlands) featured foot rest/stove guards as you mention. They are ergonomically comfy and foot warming functional, as you mention. I’m a huge fan of these for these two reasons. Some call them “drunk fences”. 🙂

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