Recently, you may have read the news about the fire at Driftwood Public Sauna in Milwaukee. Fire caused a total loss of the newly built facility, which looks to be a building on a trailer parked near the waterfront.
My sympathies to the owner, Derek Collins, and his team who clearly put their heart and soul into this project, which looked beautiful in the before images. As a small business owner, this is a worst nightmare scenario. Even with good insurance, recovery will be difficult (there is go-fund me page).
But let’s not all go running away from wood fired saunas with this image glued to our minds. Woodburning sauna stoves installed correctly are not dangerous.
Sure, the old Finns would build their saunas away from the house because, well, sauna fires do happen, and even the old sauna at Podunk clearly toed that line many times, evidenced by the seriously charred wood we found when we deconstructed it. But modern stoves and the associated chimneys are engineered and tested to heat a sauna. They are not cobbled together like the way the pragmatic old Finns did things, fabricating as much as they could from scrap metal. And neither should you be cobbling things together and taking safety shortcuts.
The fire is “under investigation”. Looking closely at the image of the fire, I know exactly what caused it. Fire rises; the lowest charred point is the point of origin.
I know that stove: the Harvia Legend Duo 300. It is meant to be fired from the outside— which is perfect for a public sauna where the fire tender has to do their job while staying invisible. According to the instructions, It is meant to be fired through a masonry firewall (see above instructions) with a minimum of 12“ of masonry one each side, yet in the photo of the fire I see plywood right next to the stove. I don’t want say it, but WTF?
On the inside there is (was) a tiled fire shield with what looks like the appropriate 1” air gap behind the stove extending to the ceiling. This looks nice, but a fire shield is not a firewall. A Firewall is entirely non-combustible, a shield simply protects a wooden surface behind it.
The plywood clearly got too hot (remember Ray Bradbury’s Farenheit 451: the temperature wood and paper combusts!) A hot stove will reach well over 1000°F on it’s surface, and so will anything touching it. I’ll actually let mine get to a dull cherry glow on top (that’s 1300°F) just to test my installations.
I go to job sites where there other contractors working, sometimes on my designs, and I commonly see manuals tossed in the trash and my written instructions totally disregarded.
I know reading is hard ( and harder when you turn fifty and need cheaters to read anything), but, sometimes the obvious is right in front of you: you just have to read it. I cringe when I see online images of woodstoves installed too close to combustibles. It’s not like speed limits—10 inches means 10 inches. And the sauna elf will enforce that!
Wood fired saunas can be dangerous—but so can anything installed improperly. Me, I’d rather run from a burning sauna naked then get zapped with 240 volts while barefoot. Let’s keep building wood-fired saunas, but safely.
These days there is a lot of internet banter about obtaining “perfection” when building a sauna and often dogmatic rules pertaining to bench heights, ventilation, wood selection and so on. I also see frequent reference to a quote that says the only good sauna is a Finnish (made in Finland) sauna and that all saunas made in the US are bad or worse. Mostly I to try ignore it all and stay focused on continuing to build quality saunas.
This week we are taking a break from all of it by doing a Nordic ski Vacation at Lapland Lake—a wonderful family oriented Nordic skiing center in the lower Adirondacks where incredible amounts of snow are still on the ground in March. The center was built by Olavi Hirvonen, a Canadian born Finn who was raised by his grandparents back in Finland then came back to the US, eventually skiing (cross country) in the 1960 Olympics before continuing on as a carpenter near New York City. A family tragedy made him re-evaluate his life goals and led him north to Lapland Lake where he bought a chunk of the forest, built a lodge and guest cottages, and developed some of the finest Nordic ski trails in the Northeast.
Everything here bears of the mark of a Finnish carpenter, much of it reminiscent of Podunk, which was also built by a Finn. The simple construction, low ceilings, unique trim detailing, and pragmatic design prevail. When you come upon the lodge after driving miles on rough forested road the unfamiliar will be taken aback by the lack ostentatiousness. This is not built in the tradition of the great Adirondack camps, such as Sagamore.
The Finnish flag flying out front (next to the American, Swedish, and Norwegian flag) is the most obvious clue that you are here.
The lodge is an oddly proportioned structure with an asymmetrical gable roof and randomly placed windows. This is snow country where the snow often reaches the second story of houses; things are built to survive that and roof lines often extend to cover adjoining walkways or combine buildings into one. It also an economically depressed area; people make do. I’m sure when Olavi settled here, his carpenter’s salary did not leave him with piles of money to spend on fancy embellishments.
His dream and his Sisu were his capital and hard work went into everything. It is obvious, from the level of upkeep, and signs of industriousness, that the current owners continue that ethic.
Inside, the main lodge is homey and comfortable, a modest main room with a fireplace to relax after skiing, a very well stocked ski shop, an upstairs cafeteria, and a sauna down in the back. It is here that I want to focus my thoughts. At first glance the sauna is a rough affair- it has an ample dressing room with a simple phone booth-style fiberglass shower. The ceilings throughout are low, under 8 feet, and the detailing is plain. But it is clean and welcoming. Classic 1980 sauna etiquette cartoons are on the wall as well as the typical signage about adding more wood to the fire and other house rules. The bench lid lifts to reveal a firewood storage; a classic sauna detail.
The hot room door is a heavy wooden affair with a rustic stick hardware pulls. Inside the sauna is about 10 x7 feet with the wood stove ( and a defunct auxiliary electric heater) at one end with a cement block chimney behind the stove. The stove (or Kiuas) is the familiar Helo, same as the Narvia Kota Kuru, similar to the Harvia M3. This is a basic Finnish model wood burner that has been in production for almost half a century. The walls and ceiling are rough #3 cedar, commonly used for fencing, but there is a smooth back rest to lean against. The benches are pine 2 x 6’s, smoothed (butt worn!) by years of use. Heavy rust stains indicate that no stainless steel was used but the benches seem pretty solid. The whole room has that darkened patina of a well used sauna. One could say the style, if any style at all, is dated, but that is not the point, it was clearly pragmatic in design and probably the first thing Olavi built. The rooms suit their purpose today as well as they did 48 years ago. Most importantly, it is kept clean, is able to get hot, and produce a nice löyly; which is more than I can say for many, many, saunas I have experienced. When I peeked back in the following morning, the floor had been rinsed and the duckboards were propped up to dry—always a good sign.
At the end of a day spent skiing spring conditions on perfectly groomed trails, the sauna was as perfect as I could have wanted it to be. It was hot (200° F plus) and ready for me. I did a few rounds of heat and löyly followed by rolls in the snow.
I did the ritual solo but Scarlet had the pleasant company of a new sauna friend during her rounds. There is nothing I would take away or add to it. This was built by a Finnish carpenter, raised in Finland, who had more Sisu than most—how can I even begin to judge that?
The conundrum I face as a builder of Finnish style saunas, is that I would never build a sauna like Olavi did. I know too much now. My purpose now is not to just serve that basic need of a hot sauna at the end of a hard days work or play, but to serve the increasingly diverse needs of a range of clients. Because one client will demand “perfection”, the bar is raised on all of my work. It would be criminal if we did not use the best available materials and accepted building practices. The competitive demands of the web require that each build be not only perfectly functional but photogenic as well. And the economic demands of running a business and supporting ourselves require that we have to balance making a decent profit with making quality products. We achieve that by marketing to a higher level clientele rather than cutting corners—but those higher expectations of what quality looks like and what it costs, cuts out the poorer customers, the common folk, whom we still want to bring sauna to.
Olavi built his dream resort before the web existed and before the current sauna revival. He depended on word of mouth and yet had a steady stream of returning customers and sauna devotees who continue to enjoy the simple pleasures of this modest haven.
Built on a budget, maintained for years on a shoestring and resourcefulness, and driven by his Sisu, or perseverance, Olavi achieved a level of quality that may now be lost to the frenzy of our internet driven times.
Note: Olavi Hirvonen died in the fall of 2024 at the age of 93. The new owners, Kathy and Paul Zahray, are committed to continuing the traditions at Lapland, including keeping the sauna hot!
Recently, on our return trip after delivering one of our mobile saunas to a location south of Boston, we visited the old sauna camp at UKTS in Pembroke. Uljas Koitto (“Brave dawn”) Temperance Society (UKTS), was founded in 1890 in Quincy, Massachusetts.1 The sauna and camp on Furnace Pond started in 1926. The temperance movement was popular at the time in the US and elsewhere and eventually led to the Prohibition Era. It is refreshing to know that temperance (the abstinence from alcohol) is still practiced in many places, including UKTS. The challenges of life that many hard-working Finns endured at the end of the nineteenth century made it essential to have access to a place that was free from excess with a cleansing sauna—especially since many had no other way to bathe.
As it was then, sauna is still the perfect antidote to many of modern life’s excesses.
After email introductions in the weeks prior, UKTS members Kurt, Audrey, Kenny, and John enthusiastically greeted us when we arrived for a tour on Friday. The camp reminded us of the great Adirondack camps open for tours where the clocks stopped a hundred years ago. But also of an intimate family cottage, passed down through many generations, with mementos on every wall and in every nook and cranny. Entry into the spacious main lodge was through the kitchen, which contained two massive vintage wood-fired cook stoves that gave credence to the stories of a full roster of members crowding the dining hall after the Saturday sauna. Audrey showed us the many bedrooms upstairs available to members for overnight or week-long stays. Each was appointed with a specific monochromatic color palette of fabric and furniture in a timeless way. I felt I was in Finland, far away from the generic American consumer-frenzy-driven design aesthetic. Audrey, Kenny’s wife, had hand-picked all the items from various flea markets and other low budget sources—typical of the Finnish Pragmatic Design that I admire and strive for in our saunas.
Each room relieved the eyes and the soul.
John pointed out photos and news clippings about past members that lined the common room walls: parents, grandparents, and great grandparents. Current members had to be distant cousins, at the least. There were also photos of athletic events held at the camp, inspired by a local Olympian. These reminded me of my days at Podunk, training for ski marathons with the help of former Olympian Jack Lufkin. During that phase we integrated daily saunas into our Nordic skiing workouts.
Sauna from the women’s side. Everyone is welcome via invitation.
Finally, we got to explore the sauna: one of the most authentic Finnish-style group saunas I have ever seen. It is a long, low affair, reminiscent of bunk houses and dining halls at any summer camp. There is a symmetry to its design with men and women entering from opposite ends. Both hot rooms are fired from the center with a new, massive, twelve-hundred-pound steel stove (Kiuas). Almost center, that is; careful investigation revealed that the stove was off center by quite a bit, favoring the men’s side.
The stove holds an equally hefty pile of sauna rocks—the one product imported from Finland. Amusingly, the saunas are connected by a small door, to be used only in emergencies. I can only imagine the mischief this might inspire in a less reserved group. The exterior siding is Pine Cove shiplap, which has that classic rustic camp look, painted green to harmonize with its woodsy surroundings. (Many of my sauna builds have this same siding.)
There are no plate glass windows or dark stained imported woods, no glass doors or polished stainless steel, and no fancy tile work. The sauna is basic and functional: a dressing room with benches, cubbies, and hooks for clothes; a shower room with plain white wall tile; duckboards on the floor; and shelves for soap and shampoos. The hot room has several tiers of benches made of crude pine 2×8’s, just like the sauna I grew up with. Most telling of the care that went into the sauna was that on our tour day, Friday, the duckboards were propped up to dry, the windows and doors were open for ventilation, and the place smelled clean and fresh. Members are divided into four teams, each team taking a week of the month to maintain the sauna, including the weekly ritual of prepping and firing, as well as cleaning it afterward. Unlike most public and gym saunas, which tend to be dark musty affairs, you could sense the members’ pride in its maintenance.
Inside the Traditional Finnish Sauna at UKTS
We returned the following day for Saturday sauna—a tradition going back almost one hundred years. We were welcomed with the same congeniality. After briefly socializing, we headed to the sauna, Scarlet to her side, me to mine.
There was a moment of apprehension at this point: we’d been separated for the first time in days, each entering a foray of strangers. Yet, at the same time, there was an incredible familiarity in the hot room. Sauna is a ritual that Scarlet and I have known and loved for years. The only awkwardness was over clothing—to go nude or not. Despite being instructed on the local custom (nude inside was OK, outside was not), I wore a bathing suit. It felt strange to have fabric between heat and body, bench and butt. But we weren’t in Finland. Americans long ago succumbed to the oddness of swim-suit sauna baths.
Inside, the heat was just right, hot by my standard, but airy. I lingered, perhaps too long, in jovial conversation. I wasn’t the youngest one present, but the years were weighted heavily beyond mine. Charlie and his slightly younger brother recalled their first saunas at UKTS in the early ’50s—and their recent hockey games! The women were fourth and fifth generation members and still taking sauna every Saturday. They were eager to share the history of UKTS and had many lovely stories of their experiences in the Finnish community. Scarlet and I were welcome and known by our business. Folks asked a lot about our sauna projects. The recognition was nice, but I’m sure they would extend the same warmth to anyone.
“All are welcome to come” via invitation, and they hold the time-honored Finnish belief that “everyone is equal in sauna.” The organization also hosts community events including Queer nights and AA meetings at the camp. They encourage new members and continue to share the Finnish sauna experience with others.
After each round, we dipped in the lake. The water was clear and just cool enough to offer a refreshing jolt but not prohibit lingering. If Scarlet and I timed our rounds just right, we met in the lake. After several rounds of sweating and dunking, we relaxed on wooden benches on the shore, snacking on a fruit plate provided by the week’s working group. There was no plastic furniture or other evidence of our disposable culture at the camp. A nice detail we reflected upon later. Although I’m pretty good at pinning dates on when things were made, there were no clues (other than the new Kiuas) that spoke of the twenty-first century or even the second half of the twentieth.
The experience was timeless. As were the people.
We had a planned stop on the western side of the state that evening, so we had to rush off after two hours; otherwise, we could have basked in the warmth of the UKTS camp for hours, enjoying good food and conversation and surrendering ourselves to sauna time.
Epilogue: Later, discussing our experience, I learned from Scarlet that although the men’s side was pretty darn hot (220°), the women’s, not so. It turns out that the new stove, a beast welded up by DC Welding in Ipswich, NH, was placed in the same location as the old stove, which was offset toward the men’s side. This means that the women’s side is always cooler than the men’s. I appreciate that UKTS honors tradition, but there are some traditions that are worth tweaking.
NOTES:
1. The Uljas Koitto Temperance Society (Noble Endeavor Temperance Society) promotes temperance and healthy living through the benefits and virtues of the traditional Finnish sauna. Founded by Finnish immigrants in 1892, UKTS provides an environment free of the influence of drugs and alcohol. The UKTS is a membership organization and not open to the public. They are a welcoming society and invite those interested in learning more about the UKTS to use the Visit Us form on their website.
I love physics because it deals with the tangible effects of the forces of nature, the interactions between matter and energy that explain the things we feel or see daily. In this post, specifically, I want to delve into the transfer of heat, which seems to be a hot topic in sauna forums.
There are three methods of heat transfer: conduction, convection, and radiation. In a sauna and everywhere else, unless you live on a planet at absolute zero (-460 °F), all three types of transfer exist. Heat always goes from a warmer object to a cooler one, and closed systems are entropic, that is to say, if you sip too slowly, the ice will melt, and your cocktail will eventually be at a lukewarm room temperature. The transfer of heat is greater when the temperature difference, Delta T (ΔT), is greater. In addition, it slows over time, until the system’s temperature equalizes, which, for our study, includes not just inside the sauna, but the environment it sits in. Meaning, no matter how well you insulate it, the sauna will eventually reach the ambient outdoor temp, unless you keep the heat on as in a house (or a sauna in a house). This is a factor in freestanding sauna design. We must assume the starting point is anywhere from 0 to 100°F (unless it is fired up constantly) and the desired bathing temp is 180-220°F. In a house, we are trying to hold the temp at about 70°. In the residential sauna, we need it to hold temp for a few hours, at the most.
Conduction is the transfer of heat from one solid or liquid to another by direct contact. Grab a (foolishly installed) metal sauna doorknob that is either 200°F leading into the hot room from the dressing room, or 10°F coming from outside into the dressing room (depending on the season), and the heat will rapidly conduct either to your hand or from it, followed by your shriek. Same is true if someone bumps you against the hot stove as you leave the sauna, burning your butt to the point where sitting is impossible for two weeks…as happened to me once. This form of conduction is typically avoided in the sauna, but it happens. Less dense materials, like your towel, mitigate conduction. This is why we look for low density boards like cedar, not hardwood, for the benches. Black walnut would feel like a hot iron on your posterior.
Convection is the transfer of heat through the movement of fluids. It is in part driven by gravitational forces; whereby, warmer gases or liquids, which are typically less dense and lighter, tend to rise while cooler ones sink. This creates a convective loop as the heat is circulated to the walls of the room, for instance, or to you on the top bench, at which point the air cools and falls, creating an endless loop. I say typically, because there is this oddball exception: water close to freezing gets less dense and thus freezes on the top of a lake or pond, making hockey, ice plunging after a sauna round, and life on this planet possible. If the movement of air is stopped, say by the fibers of mineral wool or two close layers of glass, it becomes an insulator. Air itself holds very little heat per volume (more than a thousand times less than water); whereas, water holds twice the heat energy of granite and about the same as steel. A large volume of this dense heat-holding material is called a thermal mass. By acting as a reservoir of heat, this mass can mitigate the fickle effects of convection, especially when the air is coming and going. This is why we try to keep the door closed in the sauna: The air convection that swirls invigorating heat around us is disturbed by the cold air rushing in to replace it. But that’s not so bad. We want some fresh air circulating and enough thermal mass to mitigate the swings in temperature.
In home construction, the emphasis is on controlling convection: eliminating it inside wall cavities and not allowing warm air to escape from heated (conditioned) spaces. This is especially necessary up high where warm air creates a chimney effect; whereby, escaping warm air creates negative pressure and draws in cold air from wherever it can. In a not-so-old house on a cold night, put your hand over the wall outlets, even on interior walls, and you will likely feel cold air being sucked in. More so if you have a big, cozy, romantic fireplace with an actual chimney and a roaring fire, which feels great but pulls the heat right out of your house.
In a freestanding wood-fired sauna, there will be leaks and cold air coming in. Again, that’s ok because we want fresh air, as long as we control where it comes and goes. Air and steam will move the heat around, but eventually, it settles into strata: hot up high and cold down low. Air movement can help break up this layering of cold to hot, but it is difficult to control. Thus, the upper bench will always be hotter, unless you have an Aufgussmeister to move the heat around with his swirling towel dance.
The last method of heat transfer is radiation. Sounds bad, like Chernobyl, but radiation is everywhere. All objects with a temperature above absolute zero (−459.67 °F ) emit thermal radiation, mostly in the infrared range that we can see with a special camera. At a certain point, heat becomes visible light, and the color of the light corresponds to a specific temperature. The dark red glow of a poker in the fire (or the top of my sauna stove when I fire it hot) is 1200°F (these are specific colors-blacksmiths, for example, will have a color chart on their shop wall from dull red to bright yellow). The surface of the sun burns at 5772° Kelvin, which is the color of the sunlight we bask in on the beach. Fortunately, the sun is far away and appears relatively small; otherwise, we would burn up instantly. The human body radiates heat as well. After getting sunburned, your skin will be hotter than the person next to you and will radiate heat to them. In fact, all bodies, especially black bodies1 (which are not necessarily black), radiate and absorb heat, depending on which is hotter. The only things that are not black bodies are things like foil, which reflects most heat directed at it. Surface area and angle of incidence also matter: The more surface area and the more parallel two surfaces are, the more heat transfer. Temperature difference matters as well. Too much difference and the effect is intense, like when I pour bronze and have to stand an arm’s length away from the pot of molten metal, or when I stand on a subzero surface in winter and feel the heat being sucked from my body. Too little difference in temperature (ΔT), and radiation is hardly noticeable. Direction is also important. The fireplace heats our front but not our back. I have a story about a cold, drizzly camping trip when all my companions and I could do to stay dry was to keep putting our jackets on backward then forward as we sat by the fire. And in all these situations, it is aluminum foil that saves the day: as an apron to wear, a foil surface to stand on, or an emergency blanket over the shoulders. Foil blocks radiation, but it needs an air gap, lest it become extremely conductive. Without any barrier, heat—like light, radio waves, and the rest of the electromagnetic spectrum—can radiate millions of miles. Those episodes of Leave it to Beaver from your parent’s childhood are still traveling through space.
In the sauna, radiation is crucial as it creates an enveloping heat that comes at the bather from everything hotter than 98°F (body temperature). If the whole room—walls, benches and rocks—is 200°F or more, we will feel the heat coming from each of those surfaces. Colder surfaces like a big window or that guy that just got out of the cold plunge will suck heat from us. Something too hot, like a blasting fire in a single wall stove pipe, will feel searing. In an electric sauna, the rocks need to cover the heating elements, so we don’t see/feel the searing red heat. The much cooler, but still hot rocks will then re-radiate the softer heat. Foil behind a cedar wall (or other wood) will reflect interior heat leaving the building back toward the cedar which will re-radiate toward the interior. The walls need to be just so hot. Radiation also mitigates the effect of the constantly changing air. The air may be cool, but the radiation of the hot surfaces will cut through the cold like the winter sun on your face. (Speaking of which, there’s nothing like a full-body sun bath on a calm, freezing day to boost the sauna experience!) The thermal mass mentioned above will continue to radiate heat even if the door is left open. Cool air swirling in will kill the radiation buzz for sure, but as soon as the door is closed, that warm fuzzy feeling will come back.
So how does all this daydreaming back to high school physics class inform how I build my saunas? A lot. I want the radiant heat off the stove to work for the bathers, warming them just so, like the sweet spot in the campfire where campers should roast a skewered marshmallow (but never do). I aim for a soft radiant heat with a ΔT of a few hundred degrees at most (the bather: 98°F, the rocks: 400°F); an omni-directional heat, which gets all the walls and benches up to 200°F before sauna time; and a not-too-intense heat. (Make sure the fire has died down, and the stove pipe, if single wall, is not too hot.) A big window is pleasant to look through, but it must not be too large, as it will suck the heat away from bathers, and a cold cascade of negative convection will sweep over the floor. Thermal mass is great, but again it must not be too substantial because the sauna will take forever to heat up, and no one seems to have the time for a daylong sauna ritual as in the days of old.
I have my bathers facing the rocks. Typically, the stove is fired from outside, so there is no worry about the intense (visible) radiant heat through the firebox glass door. As cozy as that sounds, it may feel too much like sitting around a hot campfire, and that is not the quality of heat you want in a sauna.
Recently, in an online sauna forum, I read two seasoned sauna veterans stating, “you don’t want radiant heat in a sauna.” I believe they misspoke. High intensity radiant heat does not belong in a sauna, but a lack of radiant heat is only possible if all surfaces, bodies of mass, and liquids have reached a state of equilibrium. That is to say, equilibrium can be reached in a sauna of 100°F or when it is as hot as the rocks, in which case, the bather is cooked like a goose. As long as the bather is cooler than the rocks, stove, walls, and benches, heat will radiate to them. It is said that when you close your eyes in a good sauna, you cannot tell where the stove is.
How do we get there? Install radiant foil behind the wood walls (with an air gap) so the foil can reflect heat back into the wood and back into the sauna; use a high-rock-capacity stove or heater (thermal mass) to hold and radiate the heat; fire the kiuas (stove) hot to get the rocks and the whole sauna deeply heated, but let the intense fire die down before bathing; and make sure everyone faces the stove, so the radiant heat (which travels as waves, like light) reaches everywhere.
You can always tell when a sauna has good löyly; everyone coming out looks so… radiant!
The old sauna at Podunk had two rooms: a small dressing room and the larger hot room. The old Nippa stove sat between them, embedded in a masonry wall. Sitting on the benches we stared at the business end of the stove with its pile of rocks, and the stove was tended from the dressing room side.
This arrangement always made sense to me and is how I have been building my saunas for thirty years. I learned to weld in art school and set up my own studio soon after. Ozzie, the owner of the Podunk sauna, would send people my way for stove repairs. After seeing how other stoves failed, I designed and started making my own stoves using much heavier plate on the top. In the older stoves, the heat would soften the thinner steel and typically lead to collapse under the weight of the rocks. I also kept to the external feed (thru-wall) and designed my stoves to be fired exclusively that way. As kids, we loved to pretend we could speak Finnish by stretching vowels and jamming consonants together to make up Finnish sounding nicknames for each other. I called my stove the Lämpimämpi by combining Lemp and Memp. Finns will chuckle at this because it translates to warmer.
I called my stove the Lämpimämpi by combining Lemp and Memp.Finns will chuckle at this because it translates to warmer.
There are so many advantages of the external feed (thru-wall):
The fire-tending, and associated ash debris, is kept out of the hot room, and you don’t have to tramp in and out with your boots on to tend the fire.
Venting a small space can be complicated; a sauna stove requires significant combustion air which can create drafts, or worse, steal oxygen from the hot room. The external feed draws air from the dressing room or outside.
Any stove front requires thirty-six inches of clearance to combustibles in front of it. This can’t be mitigated by heat shields. This severely limits the layout of the hot room. However, it is easy to get three feet in front of the stove in the dressing room.
Any stove also requires a noncombustible hearth (stone) eighteen inches in front of the stove. Hot ash and coals falling from the stove are a major source of fires. In a crowded and dark sauna room, these hot coals can easily be overlooked, fall under duck boards, etc.
A flickering flame may be romantic site, but it is the soft heat off the rocks you want, not the searing radiant heat you get from sitting in front of a blazing fire.
Typically, the fire may be almost out by the time the sauna is ready. The rocks should be the focal point. Also, following the 36-inch rule above, you can’t have the stove front facing the bathers, unless the sauna is excessively big.
If you are providing a sauna experience for others, you can discreetly tend the fire without interrupting the bathers or invading their privacy.
The external feed or thru-wall stove heats the dressing room just enough to allow hanging out and watching the fire while the sauna heats up.
Installing the external feed may seem daunting, but it is not that difficult. A firewall with the requisite size opening will be required. This can be achieved in different ways: solid masonry, which will add thermal mass (the sauna will take longer to heat); or a hollow insulated firewall with steel studs and cement board, tile or stone facing or stucco over metal lathe (which I typically use). A metal sleeve will be provided with the stove to dress up this opening and provide further heat shielding. My Lämpimämpi stove has an integrated heat shield/rock basket that works with the wall opening so that fresh air coming in is heated directly by the stove and directed over the rocks. This is an advantage over simply having the rocks sit on top inside a steel box. As with any installation, all listed clearances need to be adhered to, but with this method, the stove will take up less space in the hot room and make for a cleaner presentation. For your next sauna, consider this traditional, thru-wall approach to situating the stove.
Learn more about the Lämpimämpi Sauna Stove >
The custom-built wood-fired Lämpimämpi sauna stove that is packed with rocks on the inside and mounded up on top. This minimalists’ dream sauna stove has the elegance of a well-designed sauna stove and the function of workhorse getting to the high-temps you desire for many years. Hand-built with character. This sauna stove has been featured in our mobile saunas and freestanding saunas for over 30 years. About >
The use of stick hardware is an endearing feature of our saunas that falls under the rustic elegant motif that we employ. This hardware also falls under the category of Finnish Pragmatism that is an influence in my design; whereas, superfluous embellishment is avoided and using what is at hand is always desired over spending for what you don’t really need. In my head, I keep an inventory of all the random parts I have collected over the years and stowed away in my shop. When a need arises, I quickly do a mental scan and see if something in stock will do rather than going to a hardware store or jumping online.
Likewise, I often resort to Nature’s Hardware Store when I need things like door pulls and towel hooks.
It is amazing the variety of parts I can extract from the intricate workings of a tree.
The best is hickory because of the way branches crook when they take off in a new direction, and it is very hard. In fact, they make baseball bats out it. Recently we had to fell a Hickory, so I salvaged all the door pulls and towel hooks I could from it.
wood-fired outdoor sauna
The spirit of the tree will live on, greeting sauna users with a sturdy handshake each time they enter the sauna.
It’s the small personal touches and attention to detail that makes us proud of our work and makes our work fun and enjoyable. By avoiding the cold and the common place, we make each sauna as unique as its owners.
THANK YOU for you enjoying my blog about saunas and sauna building. If you value the info you glean from my sauna blog consider dropping me a TIP via Venmo or via PayPal @RobLichtStudio or writing a google review. For press Inquiries please contact me directly.
