If the heart of the sauna is the kiuas, or sauna heater, then the soul is the rocks.
—Rob Licht
Every brand of heater I’ve installed has a different approach to the rocks. Some, like a wall hanging 6 or 8 kilowatt unit, use less- maybe 40 pounds, and some, like the Harvia Cilindro or Club heaters use more— up to 200 pounds. Wood burners vary too, Kuuma’s heater takes 150 pounds or so, but you have to provide your own. My own custom built stoves ( Lämpimämpi ) take a similar amount and like the Kuuma stove, the rocks are piled on top, mounded as high as you can. The Harvia Legend, an elegant wood burner from Finland, basically has a cage that surrounds the stove. By the time you are finished loading it, you won’t see the stove. There is even an optional cage that surrounds the stove-pipe to hold even more rocks.
The Finnish and Swedish heaters use Olivine Diabase or Peridotite, igneous rock found in Scandinavia. All of the rocks I have used that come with the electric heaters look the same: grayish chunks, some flatter, some chunky, all in the size range you’d find in a bag of potatoes. These are amazingly cheap considering that they come all the way from some quarry in Finland or Sweden. The UPS driver has stopped asking what is in the boxes (“yup, rocks”). Once I found a note in one from a young Swede hoping that I was happy with my rocks.
My favorite rocks are hand selected glacial erratics: various igneous granitic and metamorphic stones that I find in places where glacial melt-waters sluiced out potato sized rocks. (shown below) These are heavier and denser than our native shale, which is worthless for the sauna since it tends to explode when heated. They have a crystalline structure that you can usually see and a solidity and heft that is evident when you pick them and bang them together (they are not easy to chip.)
Lämpimämpi with Glacial Erratic RocksLämpimämpi with Jagged Olivine Diabase Rocks
A big consideration when selecting a heater is the rock capacity. The more rocks, the longer you should let your sauna heat up. Clients always ask:” how long should we let it heat up?” While I usually say “about 45 minutes” I really want to answer with the same sort of retort I give when someone asks how long will take for paint to dry (as long as it takes). The correct answer should always be: the sauna is ready when the rocks are hot enough to produce good löyly or steam—löyly is the soul of the sauna’s mysterious expression. And how hot is that? 450° Fahrenheit, more or less. If you want more steam, then you want more rocks.
Löyly is the soul of the sauna’s mysterious expression.
—Rob licht
If you expect several rounds or people coming and going, then more rocks are good. No one wants to pour water on the rocks expecting a stimulating burst of steam (but not too sharp) only to hear the fizzle of water barely boiling. That’s like trying to make an omelet in a pan that is barely hot. Disappointing, to say the least, but also bad for the heater. There’s Finnish saying that goes something like this: when you leave the sauna put another log on for the sauna elf or he will pee on your stove. Which means, don’t keep throwing water on the stove, especially at the end, if the rocks are not hot. The warm water will just sit on the steel stove and rust it. When you throw water on the rocks, it should all turn to steam and when you are done, the stove should dry quickly. When I finish eating my omelet, I rinse my cast iron skillet and let it dry over the flame, I don’t let it languish all wet in the dish rack; same principle applies to the sauna stove.
Jagged rocks will catch and momentarily hold more water, allowing less to get past the rocks and into the heater. The dense roundish rocks I use produce a nice soft steam but they have to be hot. I’m not so worried about water getting down to my stove, which is always very hot (and mine have 3/8” steel plate on top so they will never rust out). By the way, always use clean water and be wary of city water with chlorine or even country water with minerals or methane. We use only use filtered water for löyly at home. Spring water or distilled water might be prudent in some cases. Never use pool water or worse, let some disrespecting novice wring out their bathing suit over the rocks, as I have seen happen in a gym. Pleasant smells should emanate from the rocks. Special sauna oils or even Sauna Brew can be added to the löyly water for aromatic effect. Heck, we used to add beer to the water (cheap lager was always best).
Custom Sauna with Harvia Cilindro with carefully placed olivine rocks.
If your electric heater comes with the grey jagged olivine rocks, I suggest using them. They are selected to fit between and around the elements. When setting the stones first I rinse them, then I take care to arrange the rocks one by one. It can take me 45 minutes to fill a large capacity heater. For the Cilindro, I place large rocks at the bottom to hold up the others and then work a flattish layer against the cage wall. I then backfill the rocks against the elements with smaller and irregular rocks. On the smaller wall-mounted units I try to fit the flat stones between the elements without forcing or bending them. The goal is loosely fill the cage so there is good airflow and to completely conceal the elements. Lastly, I top off the heater with larger stones and try to arrange them so they will catch water and force it inward, not splashing it out. In Finland there might a “spirit stone” placed here: a special stone or stones from a favorite place (make sure it is igneous or metamorphic—test it in a campfire first if not sure). The top might even have a layer of more decorative stones, which in Finland you can buy from sauna dealers, but here in the US, I have only seem the same dull grey stones. The Harvia web page has a good section on stones and how to place them into the pillar.
Once you have the sauna going and have been using it for a year or so, expect the stones to settle and flake off. You should remove them, vacuum out the heater and replace the rocks loosely, discarding the broken ones and adding more if needed. Failure to do so will cause the heater to eventually overheat and lead to the elements failing.
Care in selecting and placing the rocks will ensure that your sauna…. Rocks!
Wood-Fired Mobile Sauna by Rob Licht Custom Saunas.
Although Glamping is a term that was coined in the early 2000’s, the concept of an adventure in nature bolstered by all of the modern conveniences one could muster, or have mustered for them, has been around for well over a century and a half. In 1869, writer William H.H. Murray of Boston, extolled on the virtues of experiencing the Adirondack backwoods in his book Adventures in the Wilderness. This inspired an avalanche of urban neophytes to flock to the woods in search of adventure and commune with nature. These were known as “Murray’s fools”.
People traveled great distances and endured great hardships such as days of travel over log roads (which were literally made of logs placed side by side) to get to the heart of the Adirondacks. Once they arrived, they sought out the services of guides who did everything for them—transporting them in their guide boats, making camp, catching and cooking their meals. In essence, these early Glampers brought with them from the city every expectation of service they would get at the finest hotel.
“The mountains call you, and the vales: The woods, the streams, and each ambrosial breeze that fans the ever-undulating sky.”
—Armstrong, Art of Preserving Health
Glamping experience enhanced with a sauna (banya) in tow.
While part of me chuckles at the concept of Glamping with it’s pretense of tender-footedness, part of me is drawn to concept of rustic luxury. Although I am as far from a camping neophyte as one can be, with years of deep woods experience and many a night sleeping on hard ground, the concept of luxury camping does have certain appeal to me now. I’ll sleep in a tent on a platform—with lights and heat and maybe a commode. But better yet, with a sauna.
The idea of communing with nature combined with sauna is perfection—and something, I bet, even the luckiest of Murray’s fools never had.
View of the mobile sauna looking out through the dressing room to the campsite. Pile of rocks sit on the Lämpimämpi stove.
Most people glorify the act of building, as in being able to transform a humble pile of building materials into a noble sauna or house or shed. I like to think that too: that my profession is a noble one, with an emphasis of craftsmanship and attention to detail that can only be honed by decades of working with fine materials. But the truth is, on any given day, on any given project, especially for on-site work, where I take my tools and materials, my truck and trailer, my lunch and my laptop and various other accoutrements, is that I am often just a professional schlepper. And I bet any other contractor reading this just now nodded his or her head.
I love doing saunas that are removed from the house, perhaps beyond the garden gates or down by the lake or out in the woods next to a pond. I like to work immersed in nature, take lunch by the water, and contemplate the finer things in life while I toil at my craft.
Sauna on a PondSauna on a LakeSauna in the Woods
But, when I bid jobs like these, I have learned to think of the schlep— that is the sum total distance from truck to the site. I think of thousands of steps back and forth to carry lumber, to retrieve the pencil or glasses from the cab, of the steps I have to climb or the potential for slipping and falling with a 100 pound load on my shoulder. I have literally carried an entire eight by twelve sauna on my shoulders, load by load. Some days I count the steps and do the math—how many miles I wonder? Other times I count the load— a ton of concrete mix, how much work was that?
I don’t mind the schlep. The key is to embrace it. If I know from the start and plan for it: clear the path, remove obstacles, make ramps, then I can proceed slowly but with the steadiness of a Yoga master moving through a progression of poses. Each repeated carry is perfected in the same way a bobsled driver learns to lean through each curve.
With two or people it is a choreographed movement. Go left here, stoop here, K- turn at the end and dosey-do before we enter the door. Perfecting the movement makes it almost enjoyable.
At 60 I have to protect my body. I know my strengths and limits and my strength is knowing how to carry and move heavy objects. Always keep one hand free- you never know when you’ll have counter an off- balance step. Always be relaxed and take smaller loads— there is no race. It is amazing what you can in an hour of honest schlepping. Ironically when I do have spells of days or weeks when my back is “out” and the chiropractor is needed, it always the stupid stuff that gets me: desk work (I stand at my desk now), shoveling snow or that heroic effort to rake all the leaves in one Sunday. These are unintentional actions. Work with intention and you will become stronger. Work smarter and you will avoid injury. I really like those 60 pound concrete bags— and I’m eyeing those forty’s. At 19, everything came in 100’s.
Rob – der schlep
I’ve had jobs where the schlep caught me, like the sauna-cabin in the woods where I was promised an ATV to haul everything. After the first week, 3 feet of snow put the brakes on that. Everything had to be hauled on a sled with me in snowshoes. Good thing I Loved those Jack London stories as a kid.
But then, I’ve been pleasantly surprised too- like a recent job on the lake where the haul was several hundred feet down steep stairs or a windy path. Then the owners produced a golf cart. It became my mini-truck and my morning joy as I breezed down the hill silently. There is a beauty to electric vehicles: the joy of still hearing nature as you whizz through it.
I’ve thought of offering classes on Schlepping—or even rigging—which is a specialized form of schlep that involves more weight, more dance, more cooperation. We would move things each day. And then maybe move them back again. Everyone has it wrong about Sisyphus. If the enjoyment of the act of moving becomes the goal, rather the completion of the act, then he could be seen as a master perfecting his craft. Like a cat that keeps hitting the toy away only to chase it again, a worker who carries load after load and enjoys the process will reach the goal of enjoying his or her work.
And only when a worker enjoys his or her work is true craftsmanship possible.
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It’s been a busy year at Rob Licht Custom Saunas and as the holidays approach it is a good time to look back everything that’s been accomplished, the hurdles we’ve gotten over, and to be thankful for the blessings we’ve received.
We started the year in the midst of the pandemic which made for some challenges but mostly the pandemic has meant a huge uptick in the sauna business as we all became more centered on home life and more reluctant to go out into public for things like gyms and saunas. Besides the several projects I have completed locally and around central New York I have fielded calls and emails from folks desperate to have their own saunas from as far away as Europe and Australia. I never set out to become a sauna expert, but here I am, 25 years into making them, and people are seeking out my knowledge from all over. In the process I feel like I have made many new friends. The global sauna community is alive and well. At the same time, due to the pandemic, I have mostly refrained from seeing all but my closest friends and family. It’s a strange new world but I am thankful to be connecting to so many people, if only on Zoom.
For my new friends I have designed and consulted on saunas from Maine to California— that has kept me busy when I was not getting my hands dirty. But whenever I can, I am working with my hands, either in my 3000 square foot shop, which I am ever grateful for, or I am on jobsites. It used to be that builders would simply stop in the winter and spend the dark months sitting around the woodstove reading back issues of Fine Homebuilding, but now we all seem to be out there in any weather. My cut off is 10° F; any colder and I want to be by a fire, in the sauna, preferably. Good gear helps; I’m especially grateful for my boot warmer and insulated pants.
Mobile Saunas showcased in the shop. Lansing, NY
Nothing I do is cookie cutter—I would die of boredom is life was too easy— thus the custom in my business moniker. This year I seemed to run the gamut of sauna permutations: First, a garage retrofit to a Yoga and sauna retreat, then a quiet walkout basement electric affair, then a classic one room wood burning sauna on a idyllic creek, then a more urban collaboration in Syracuse, followed by a tiny personal electric sauna in a bathroom, a rustic elegant wood burning retreat in the trees, and a distance job downstate. Currently I’m finishing up an electric sauna in a historic boathouse on Cayuga lake. I’m hoping to take it for a test drive, with a jump in the frigid water, by Christmas.
Garage Retrofit for Hot Yoga and SaunaClassic Creekside Sauna set 50 ft from swimming hole. Idyllic.Walkout Basement Electric Sauna BlissBackyard Sauna Design, Urban Collaboration in Syracuse, NYRustic elegant wood burning saunaCozy interior of a backyard sauna
In between all of these I have sold a few of my Lämpimämpi sauna stoves and many sauna plans. DIY interests, especially in the mobile saunas which are really big now. I get a kick out seeing my designs being brought to life by many different hands. It is also fun to see all of the other builders following in my steps. The more builders, the better. There is plenty of work to go around and I encourage anyone who wants to take the work seriously to pursue it with a passion. I did offer a sauna building class this year but had to cancel; Covid has thrown a wrench into a lot of plans. But stay tuned: perhaps 2022 will be the year.
Covid also threw into a wrench into the supply chain. We’ve all heard the phrase “supply chain disruption” by now. I bid jobs in the beginning of the year only see to prices on materials I quoted go up by 250%. Some materials simply vanished from the shelves. But now things have settled down and I also started ordering and stock piling materials well in advance. I can keep several saunas worth lumber and supplies in my big shop and insulate myself from some of the inflation—another reason to be grateful for the big work space.
Rob at the shop!
I’ve been working alone for most of the year, which actually suits me fine, especially with Covid lurking. Workers are hard to come by: not only are the skilled trades losing new blood, but, I think, the pandemic relief made a lot people lazy and unwilling to get off the couch. Scarlet, now my partner in everything, has been my greatest blessing. When she can escape childcare duties she has proven to be the hardest worker I could wish for. I could use a few more workers like her: eager to learn, unafraid of dust and dirt and willing to sweat. She also manages all of the marketing, so give her the kudos for the web media you see. The business feels like it wants to grow so if anyone is seriously interested in building saunas and wants to relocate to Ithaca, drop me a line.
For those of you lucky enough to have a sauna, I hope you get to celebrate the New Year in it for there is no better way to bring in the new and shake out the old. It’s been my tradition for four decades now and I hope to continue for four more.
Taking Sauna with Scarlet by the Lake, December 2021.
Lately I have been thinking about the application of the foil I use in my saunas as a radiant vapor barrier. Perhaps this is because it almost Christmas and I was thinking of how we decorated the tree each year. The final touch would be to drape foil tinsel over everything; our mother would have to constantly damp down our enthusiasm by reminding us to place it carefully on each branch, not to throw it.
This suspicious “sauna” foil is Aluminum-coated Plastic—upper working temperature of only 55-120° C.
There are tricks to using the foil but the first and most important step is to buy the right stuff. Like the tinsel we put on the tree, the foil may actually be aluminum-coated plastic— which you don’t want to use. That plastic is likely polyethylene which, if you look it up on the material specification sheet that every product has, it has an upper working temperature of 55-120° C, meaning it will likely melt at typical sauna temps. Sauna Foil, available from any of the familiar sauna suppliers, is aluminum foil on a kraft paper backing. I used to find it with fiberglass reinforcing thread, which is helpful because the stuff tears easily. Also helpful is 4 ft. rolls, rather than 3 ft so you can do a wall in 2 passes, but I have trouble finding this too. I recently tried a new supplier selling 4 ft rolls of “sauna” foil, but upon opening it had a suspicious plastic look to it. That night I put it in the sauna and within seconds it began to distort and curl up like the polyethylene I suspected it was made of. (See illustration above)
The second thing is to design the wall correctly. I read and see a lot of misinformation that touts using no air gap with foil. The air gap is essential. The foil works by reflecting radiant heat. All “black bodies” give off and absorb radiant heat that travels in a straight line from one hotter object to another cooler one, the hotter the body, the more heat it emits. The sauna rocks radiate a “soft” heat to you, the walls, and the benches, and that is why you want the sauna to be laid out so that everyone has a view of the rocks. The fire, if seen through a clear glass door, also radiates heat— but at a higher intensity. Too high for a comfortable sauna (but great for ambiance.) When that heat hits foil, it is reflected back into the room or the backside of the cedar—if there is an air gap of at least 1/2″. If it touches the backside of the cedar the foil— also a perfect conductor—pulls the heat away from the cedar and transfers to the wall space behind.
Air Gap. A Sauna Building Best Practice.
I’ve understood this for along time. The first semester of college I took a class: Solar Design and the Energy Efficient Home. We learned all about insulation, heat transfer and basic building skills. The first day of lab, where we were building a timber frame house, I was handed a Makita 12″ circular saw. My building career started right then and there.
With the web of misinformation out there I had to think of a way to illustrate this basic principle of thermodynamics that I learned my freshman year. So, one slow day in the shop I rigged up an experiment and photographed it. (see illustration below) I set up a section of cedar wall about 18″ from my infrared shop heater and fastened 2 pieces of foil to the back, one with a 3/4″ air gap, and one with no gap. After an hour the cedar was 250°F on the front—like it is often is in my sauna. The back of the cedar was 121° F, which is impressive by itself. The back of the foil with no gap was 115°F, meaning it was acting as a perfect conductor, and the back of the foil with an air gap was 71°F: room temp. The air gap was clearly making a difference, 45° in this case.
The thermodynamic experiment begins.
After an hour on cedar
back of cedar
back of foil, no gap
air gap makes big difference!
The foil is a perfect vapor barrier rated at zero perms— meaning no vapor moves through it. But unless you layer it properly, with insulation behind it, the moisture will condense on it, or the first cold surface it hits. Even in a perfect build, there might be cold spots in the insulation (typically about the size of a mouse hole), so there likely be some condensation, but not a problem if there is air movement. The air gap behind the cedar allows air to circulate around the cedar, removing any moisture and ensuring that the wood heats and dries evenly and remains stable. Heating one side of a board and wetting or cooling the other is how you make curved boat staves.
There are other tricks to using the foil- like unrolling it and re-rolling it foil-in, or using temporary magnets when working a commercial job with metal studs, but the key is to use care. Use plenty of hi-temp foil tape and patch tears as you go and work with a partner if possible.
I suppose you could build a sauna by putting a heater in a refrigerator box- but that would last about a day and be incredibly wasteful. Cedar touching foil won’t ruin your sauna and neither will plastic melting in the walls where you don’t see it. But if you are going to take the time and bear the expense of building a sauna, you might as well do it right and so it will last generations. I guess my mother was right: applying foil carefully and not just throwing it up is the way to work.
Building a sauna requires many skills. Basically it is a small house; there are windows and doors, a roof and a foundation; framing, sheathing, subfloor, and the like. It also requires a design, and many cases, a permit, which will include drawings such as a site plan, showing required set backs and orientation. All of this I can do— from plans and permit applications to foundation to chimney. I pride my self on being able to do it all and to being as comfortable holding a drafting pencil ( yes, I do drawings old-school) as I am a pick-axe or nail-gun. But the truth is, sometimes it is best to let others do the work they do best so I can focus on what I do best, which is the sauna.
Recently I had a job where distance made it much more efficient for the owners to use a local contractor to build the shell while I did only the sauna interior and the overall design. It turned out that Tim and his crew were much more adept than me at not only building the shell but carefully replicating the trim details of the 150 year-old adjacent main house. By the time I got to the job site the interior was ready for my sauna work.
Just like everyone else during the pandemic, planning sessions happened on the web or via text; we only actually all met once. Despite that, or maybe because we weren’t in each other’s hair (a sauna is, after all, a very small space), things flowed very smoothly once we got over the scheduling speed bump caused by the pandemic-induced supply chain upheaval. The sauna sits perfectly between the historical architecture of the house and the modern look of a contemporary sauna. It was a team effort that paid off.
