Authentic Sauna Blog

A great idea for your sauna floor

A word on building your own sauna and dealing with the sauna floor.

Here’s an email exchange that may offer some guidance:

Hi Glenn
The Saunatimes.com website has me a converted man…I no longer want an outdoor sauna, now I NEED one!
I live in Surrey, BC. Our winters are mild by Minnesota standards but the dampness and rain chill a person to the bone.
I have started to aquire the materials to build my outdoor sauna and have a few questions about the ideal outdoor sauna design.

1. The opposing bench design looks like a good idea on paper but I noticed your portable sauna has L-shape benches. Is there a change of “ideal”?
2. Flooring in the sauna and change area. Any recommendation on how to finish them or does bare plywood stand up alright?


And my response:


Wonderful email, and i’m glad to have helped and influenced you.  You ask two great questions:
1. “L” bench is the more ideal… yes, change in “ideal sauna” glad you caught it.
2. Plywood floor.  Yes, start with plywood as a subfloor, then:

  1. Paint it or treat plywood with a water sealant.
  2. In the hot room, I suggest screwing in a drip edge around your perimeter.  Your first row of t&g cedar can rest on that.  I rip a 2×3 green to get a 45 degree upper edge.
  3. cut and install a shower drain in center of hot room.
  4. get a couple bags of vinyl cement patch, 40# i believe. it’s cheap.
  5. mix that in a wheelbarrow.
  6. trowel it down in the hot room floor.
  7. 3/4″ around perimeter, down to about 1/4″ at the drain.

It’s a real slick system…. couple points to keep in mind..

  1. keep your bottom plate in tact where your door is, or sawzall it and screw it down so your cement has a place to stop.
  2. consider patio block where your woodburning stove will sit.  Lay that first, before cement.  trowel up to patio block.
  3. chalk line your drip edge before screwing it down to bottom plate, framing, as a trowel mark, guide.
  4. You don’t need much of a pitch if you’re sauna building is level.
  5. You’ll build cedar decking (1×4 cedar with 1/2″ spacing) on top of this.  this is where you’ll walk.  feet stay dry.

take pictures!  keep in touch.

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10 thoughts on “A great idea for your sauna floor”

  1. I just have a quick question, is there a reason you suggest vinyl cement patch instead of regular cement?


  2. Hi Saara, were are building the same sauna and have the same questions. The vinyl cement patch is roughly $30 at Lowes, did you ever get an answer to your last two questions. thanks

  3. I just finished building our German outdoor sauna in Ontario! We are sooooo happy and learned a lot in the process.
    We learned that insulation is everything, especially when you want also large windows. we even made our own door.
    So, we insulated our floor with 6″ rocksol. On top of that is 3/4 espenite, followed by 1/2 cement board, followed by a natural cut stone floor tile from Home Depot; followed by a douple layer of hard wax sealer. The cement board is fibreglass reinforced, and a must for a tiled floor.
    We did not put a floor drain in. For the few drops of sweat you may loose on the floor, you simply use a damp cloth to clean with, whenever you think it’s time. In a German sauna, we do not touch the wood with our bodys; instead we we sit on towls and make sure the sweat is caught by towls at all the times. This is nice and soft for the body and your wood will last a long time, looking like new. However, sauna wood should be treated with odorless paraffin (food grade).

  4. Hello Michael,

    I wonder if you could send me some pics of your sauna. Are you from Germany? My family moved from Germany to Canada in 2002. I’d like to start building an outdoor Sauna next year and would appreciate some pictures if possible.

    Thank you,
    Gerhard Becker

  5. Gerhard: I am from Minnesota, USA land of 10,000 lakes and fewer saunas, but we are gaining on them. As far as photos of my saunas, please search “12 16” on saunatimes. You’ll see my cabin sauna. Search “backyard sauna” and you’ll see folks detailing their saunas, as well as stumbling across photos of my backyard sauna. Hope this helps.

  6. Yes, I am from Germany (where men and women sauna and lounge together nude, without having shame or sexual thoughts). I came to Ontario/ Canada winter ’89, and settled in the Muskoka region.
    When said I just finished our outdoor sauna, I said a little too much. I still work on small things like foot benches, preserving the wood, etc.
    I started this project in July, with the goal to create an oasis, that is pleasing to mind, body and soul; they way it’s done in Germany. But since money is always an issue with such lofty goals, I did did and made everything myself including lamps, sauna bucket, ladle, etc. I documented every step and have a lot of pictures. I am not sure, how I would post pictures here. I can however email some, if I get an email address to send them to.
    Anyone, who wants to visit and check out our sauna is welcome.

  7. Hi Glenn,

    I have been building a sauna using your DIY ebook and it’s been a great help, thank you! I was wondering if you had any pictures of the duckboard you describe making in the book that you can share?



  8. Does anyone else use paraffin oil to treat their benches? I’m at a crossroads and looking for any helpful input.
    I’ve read from many people who are adamant that the wood should be left untreated, and have also read many articles talking about using 100% paraffin oil to preserve the wood.
    I’m sure there are some strong opinions here too! Anyone have a list of pros/cons?

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