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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.

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

  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.

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