External Feed Sauna stove

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.

This arrangement always made sense to me and is how I have been building my saunas for 30 years. I learned to weld in art school and set up my own studio soon after. Ozzie would send people my way for their stove repairs. After seeing how other stoves failed, I designed and started making my own stoves using much heavier plate on the top, where 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 consonants together and making 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 reasons for the external feed (thru-wall):

• The fire-tending, and ash debris are 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, rob oxygen from the hot room. The external feed draws air from the dressing room or outside.

• Any stove front requires 36 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 3 feet in front of the stove in the dressing room.

• Any stove also requires a noncombustible hearth (stone) 18” in front of the stove. Hot ash and coals falling out 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 to look at may be romantic 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 stove heats the dressing room just enough so that you can hang out and watch the fire while the sauna heats up.

wood-burning sauna fired thru-wall

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 solid masonry, which will add thermal mass (and take longer to heat the sauna) or a hollow insulated firewall with steel studs and cement board, and 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, which 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 way of building it.


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Stick Hardware

One the endearing features of our saunas that falls under the rustic elegant motif that we employ is the use of stick hardware. These also fall 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 that are stowed away in my shop and 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 “natures hardware store” when I need things like door pulls and towel hooks.

stick hardware by Rob Licht

It is amazing all the parts you can extricate from the intricate workings of tree.

The best is Hickory because of the way branches crook when they take off in a new direction, and it is very hard. After all, 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.

The tree will live on as it greets 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.


SMOKIN’ HOT

SMOKIN’ HOT

I have always been fascinated by fire. There is a mystery to it that even science cannot unravel. It is more like the fourth state of matter—plasma—than the familiar trio of liquid, gas and solid. I have played with and studied fire since I was a kid, sometimes barely avoiding serious trouble, other times under the guidance of elders, like in Boy Scouts where we boiled a quart of water in five minutes during fire-building competitions. As I grew older, burning wood became a way to heat our home. Wood cutting and splitting became not only a chore but a workout and a way to get my angst out with each strike of the axe.

After I learned metalworking in art school, I started to apply my skills to making wood stoves and thinking about what happens inside of a stove- the mysterious process where tons of wood are reduced to a small amount of ash, carbon dioxide, particulate, and other emissions that are carried away by the wind. The heat is from the atomic bonds of carbon molecules breaking, turning matter back into the energy of the sun that formed those molecules. There is something seductively simple in that balance of carbon in/carbon out, but, as we now know, there is also something deviously complicated about the carbon cycle. I have warmed myself with wood heat over the years in my home, shop, and sauna; each time I light a fire there is still this fascination and allure to the flames that draws me to it and perhaps blinds me to greater issues.

In the past 50 years, wood stoves have gone through several changes. Initially they were simply boxes with a loose-fitting door and a chimney—like the Ben Franklin stove. These stoves burned uncontrollably and inefficiently and needed constant feeding. Later, air-tightness became a thing: dampers were dialed in, rope caulk was added to the doors, and the fires were slowed down so they could burn all night. But as the fire burner longer and cooler, not all the organic matter was burned— more went up the chimney. Flammable wood gasses called creosote condensed on the cool sides of the chimney, building up thick tar-like layers. Eventually that caught on fire, sometimes taking the whole house with it. In the 70’s we went though the energy crises and wood stoves became a very popular way to deal with spiraling oil cost. The 70’s also saw the birth of the environmental movement and the EPA. The EPA stepped in as did Underwriter’s Laboratory (UL). Stoves had to be made safer and cleaner burning. Expensive Catalytic convertors—like on your car—were added to the stove outlet, to capture some of the nasty stuff. But neophytes, in their craze to burn wood, skipped the all-important step of letting firewood dry at least 2 years. The converters clogged up. The cats were dropped, and the focus turned to better engineering. Stoves are now designed with all kinds of baffles to get the wood to burn cleanly; they are complicated affairs, and many don’t work that great- they certainly don’t burn all night, or, as I used to do with mine, burn non-stop, all winter.

But sauna stoves are a different beast. Since they are “occasional use only” (and only one is UL listed) they are, thankfully, technically EPA exempt. But still, I don’t want to be “that guy” that smokes out the neighborhood every time I light my sauna—especially since this past summer when we all got a taste of the Smoke Armageddon. So, despite my years of wood-burning experience, I am always trying to tweak the process and learn the idiosyncrasies of my stove. Every stove fires differently and even a familiar stove can rebel on you when the wind changes or you when move the sauna. When I light mine, I know it will smoke some; my goal is always to get it burning hot as fast as possible so the smoke will be minimal.

The three sides of the fire triangle are heat, fuel, and oxygen. A perfect balance gives a cleaner burn. 

You can easily adjust the fuel and air but not so much, the heat. The heat in a wood stove comes from the fire itself, so, you need to get the stove very hot, as quickly as possible, to achieve a good balance. Wood emits gas when is heated above a certain point in a reduced atmosphere; this gas will burn cleaner than the wood itself. If you get your stove so hot that the wood gas burns before the wood, it will burn cleanly.  There are cars designed to run on wood gas: a heated tank of wood chips creates the gas that runs the engine. Most stoves have a baffle or two and an upper chamber where the hot gasses will hopefully combust when mixed with additional air; the real heat is at the top of stove, before it exits the flue. In my Lämpimämpi stove, the top plate, that the rocks sit on, is 3/8” steel. I will get this steel glowing a dull cherry red (about 1300°F). Any gasses passing through this chamber will be burned. But until the upper chamber is hot, gasses and particulate will escape up the chimney and the sauna will smoke. Having a brick-lined fire chamber will help the fire get hotter faster. Wet cool days will make it worse as will a down-draft caused by the sauna being in the lee of nearby trees or structures. Wet wood doesn’t help either.

Up until this week my process has been to get a small fire going briskly, with the ash drawer open, and stove door open until it starts to roar (I have an external feed, so no worries about embers falling out.) Then I add larger sticks in one or two loadings until I fill the fire chamber (nothing bigger than my arm–scrap 2×4’s are perfect) topping it with one or two small hardwood logs. The problem is, when I add the fresh wood on top of the fire, there is a period of incomplete combustion as the wood heats up, and the stove smokes a lot. If the wind is wrong, my neighbors will get smoked out. I tinker with the ash drawer or open the stove door to blast in more air until the smoke clears (another advantage of an external feed: I can watch the chimney.) I can add more air to balance the fuel, but I can’t add more heat. Think of it like the carburetor on an old car. Too open, it won’t run well, too closed, it sputters and smokes and clogs the engine. Not enough heat, and it won’t burn well either. I try to find the sweet spot. Unlike a wood stove in a house, I’m not worried about things getting too hot- better than too cool. It’s not uncommon for my stove pipe to glow red for a while—that’s ok, because I know my installation is safe.

Recently, after reading an online post, I tried a new way to fire the stove (yes, old dogs can learn new tricks): from the top down! I load up the stove with larger sticks at the bottom, then smaller, with short sticks crisscrossing between them. Then on top of this stack I put the wads of newspaper with a handful of kindling and light that. The fire immediately starts heating the baffle and upper chamber as the fire slowly works it way down. This way the flames aren’t cooking the larger sticks before they are ready to burn. This solves the too much wood/not enough heat problem.  Amazingly it only takes 5-10 minutes for the fire to reach the bottom and a hot bed of coals forms quickly. I leave the ash drawer slightly for twenty minutes and then add more wood. After that you can’t even see any smoke. When we take our sauna to one of the local parks, we can be clandestine; with no tell-tale smoke; passersby have no idea that our sauna is cranking hot inside.

I know there is a whole argument for decreasing our carbon footprint as much as possible and not burning any wood; but there is an opposing argument that says we need to maintain our ties to nature to want to save it. Controlling fire is not only as old as mankind but one of our defining traits. 

Without getting into the debate, which I’ll admit I don’t lose sleep over, I will admit that I don’t want to be “that guy”. I want to remain sensitive to others and burn my stove as cleanly as I can. Learning how to master the art of fire building is one small step to take if I am going to cling to tradition and enjoy a really smokin’ hot sauna.

Back to Podunk

Reflecting view of old Finnish Sauna from inside of new Finnish sauna.

If you look “Podunk” up in the dictionary, it will tell you that it is a hypothetical or insignificant town. The folks who live there think otherwise. Podunk is actually a place name on the map a short ski south of Trumansburg, New York, where I grew up. Despite having only a smattering of residents, they will all tell you that is very real and very significant. 

In the 1960’s Ozzie Heila settled there with this family on an old farmstead established by an even older Finn who first built his sauna (above) before the house in the 1930’s. It is also where I learned of all the important things in life. In the 1970’s I spent countless winter hours there at the ski center that Ozzie established, becoming a become a damn good Nordic skier and developing a life-long passion for the sport.

In the summers I explored the creek with his son, my good friend Daniel, and learned the value of immersing one’s self in nature. Daniel’s mother, Ethel, was my art teacher in middle school; she helped me become the artist I am today and we still have wonderful conversations about color theory and art composition. And at the heart of the complex of dated farm buildings was the sauna; there I learned to channel my need to experience extremes into something healthy and life affirming. We loved going from the hot to the cold.

Jumping in the creek in the dead of winter after a searing round in the sauna, we felt more alive than ever. That feeling has never died; each cold plunge I take during sauna takes me back to that creek.

Today, Daniel and his family were back in the area and we went to Podunk to visit the old homestead once again. This time we took our Finnish Blue mobile sauna and parked it next to the ramshackle old sauna, which is now defunct and awaiting a rebirth. Many things have changed  but some things are the same. The trees have grown huge or even died, the old purple Lilac, with the rusty sauna bell hanging from its branches, is gone and the brush has been cleared away from the old sauna, revealing the sagging bones of the century-old  structure. But the building itself is as recognizable as the last day I took a sauna there about 25 years ago. The inside is a sadder story—it turns out that squirrels like the sauna too and they have made it theirs. As if in a expression of  horror at the mess, the Lämpimämpi stove I welded up for Ozzie in the 90’s sits with it’s mouth rusted wide open. 

The path through the field to the creek is the same but with a detour to the left towards a new dipping hole: a bathtub in the midst of the rushing current with a strategically placed rock to help keep your butt moored. The run down to the creek had the same awkwardness … trying to run all out before you cooled off but trying to maintain stable footing the same. And the sensation! The whoops and hollers of 12-year-old boys came out of us as we braved the icy April stream.

Real or not, Podunk is the same as it will always be. What are memories but unreal fragments in our minds, ready to be stirred up by whirling waters of a cold stream, or by the hot steam of a sauna? The old next to the new will always appear old, until we make it new again and live our lives in the now, to the fullest, with no regrets, and dreams, not of memories, but of tomorrows.

new Finnish sauna parked next to an old Finnish sauna by the creek
New sauna and parked it next to the old sauna near the creek.

Rolling out the mobiles

Mobile Sauna traveling to the lake for a cold plunge
Traveling with one of our mobile saunas to the lake and delivering to new owners.

We have been building mobile saunas for the past 10 years! and because of their growing popularity and versatility, they now make up most of our business. Each unit is still handcrafted with many layers of details. The owners each get a unique product tailored to their specifications. It’s also an easy way to avoid zoning and permitting restrictions while avoiding the hassles of a site-built project. Investing in your dream sauna makes more sense if you know you can take it with you!

We hear from our customers all the time that their friends, family, and neighbors
are as excited as they are to have a sauna! 

Inside the hot room our mobile saunas looking out through the dressing room to the lake.
mobile sauna, wood-fired sauna on a trailer

For many people, owning a sauna feels like a bare necessity during the winter months!

Backyard mobile sauna steps away from home surrounded by dramatic rocks and fire pit patio perfect for entertaining.
This recent sauna build is just steps from the owner’s historic New England homestead. Our saunas are designed to blend in with the home and environment. The classic details of this historic house are elegant rustic with dramatic rock outcroppings and a fire pit, making for a perfect gathering spot.
Mobile sauna parked at an overlook
Our wood-fired mobile saunas travel well and can be parked in beautiful places
Ready for a cold plunge
Scarlet by the lake ready for a cold plunge

Having a sauna at home is a life upgrade that is low-maintenance.

Finnish Blue Sauna 5'x8' size
Our 5×8 ft Mobile Sauna parked in town with 100 gallon cold plunge tank.
interior mobile sauna by Rob Licht Custom Saunas with custom sauna stove
Interior of our larger mobile sauna. Our saunas can get as hot as you like with a large pile of rocks. We aim for 100°C / 212°F
We build handcrafted wood-fired and electric mobile saunas in Ithaca, NY and can be delivered in the US.
We build many mobile saunas in our shop in Ithaca, NY. Working in our 3000 square foot shop is more efficient than building on-site.
We build mobile saunas. Here we have 2 models of wood-fired mobile saunas built with locally sourced and non-toxic materials. These mobile saunas are built with the same attention as any freestanding sauna.
Two sizes of mobile Saunas on display at our shop in Ithaca, NY

We offer building plans for DIY sauna builders or your local builder for one-time usage only. Thanks to our valued sauna plan customers, and the growing popularity of DIY sauna building, we have taken the opportunity to launch our new & improved mobile sauna building plans! Our sauna plans are 50+ pages and include detailed notes, drawings, photos, and material lists for a wood-fired 5’x8’/6.5’x10′. If you are thinking about purchasing our plans or building a sauna, we offer you an opportunity to build your own sauna using construction plans. Rob Licht has developed the best practices of sauna building with 30+ years of experience.

sauna building plans >


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Finnish Blue Sauna

Finnish Blue Mobile Sauna in the Fall
Colors of this mobile sauna were inspired by the Finnish flag.

“The blue of our lakes and the white snow of our winters”

—Zachris Topelius, Poet

Finnish Blue Sauna IN the news: Read OUr Story >

Mobile Sauna Interior with the Lämpimämpi sauna stove, tiered benches and large window with a beautiful view of the fall foliage.
Mobile Sauna Interior with the Lämpimämpi sauna stove, tiered benches and large window with a beautiful view of the fall foliage.

Stay posted on the latest Finnish-blue mobile sauna outings on Instagram @saunasbyrob and facebook @custom-saunas We’ll be using this one for pop-up and promotional events in the Finger Lakes region of New York State to share our saunas and promote sauna culture.

PRESS INQUIRIES: Contact Scarlet at contact@roblichtcustomsaunas.com


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