I just completed this bright blue, yellow, and white gem of a sauna situated on a red deck. The color was the client’s choice; he wanted something that would brighten things up and be in stark contrast with the usual suspects of taupe, dull brown, and moldy blues that afflict his neighborhood and so many other American housing developments. Why are builders so afraid of color?
The use of bright color in homes is often associated with places like seaside Baltic towns and Reykjavíc, Iceland—and for good reason. In the deep of winter these places are plunged into darkness as the sun hovers near the horizon or barely makes an appearance at all. Battling the winter blues makes the use of bright colors almost mandatory. Of course these places all have saunas (or in the case of Reykjavíc, massive public hot springs), another way to survive the depth of winter. I learned when I was an artist-in-residence in Nova Scotia that fishermen traditionally used bright colors in their houses simply because it was a way to use left-over boat paint. Boats are painted brightly so they can be uniquely identified at sea, so in a way, the house colors express something unique about the individuals who live within. Now, of course, the brightly colored fishing village is almost a tourist mandate.
Looking back on recent sauna projects, I see a shifting trend in color choices made by my clients: from authentic dark-brown Viking tar to blue-grey, then brighter reds and blues and greens, and now this latest color feast. There is also a trend in current design to use more bright colors such as on the eye-popping florescent orange running shoes I saw in the gym yesterday. I have been following the designer Ingrid Fetell Lee. She writes about creating joy with color in her book The Aesthetics of Joy. She is persuasive about using more color for the simple reason that it creates joy. Although I teach color theory, I have a tendency to stick to blacks, grays, and low intensity colors in my art, a trend that I have been trying to evolve out of. Perhaps I can take some cues from my clients and take some color risks in my own work. This latest sauna project actually makes me think of late Mondrian paintings such as Broadway Boogie Woogie in which he reduced his palette to the three primary colors and sought to use color as the basis for expression.
In this latest sauna project my interest in sauna and art actually converged. The warm interior heats your body, and the colorful exterior warms your spirit. Thanks, Karl!
I just completed a large 9’x12′ sauna at Silverlaken Glampground near Letchworth State Park. The glampground is an ideal setting for quiet retreats or group gatherings: a main lodge in a historic cottage, private cabins and luxury tents next to sparkling Silver Lake just miles from one of the most popular state parks in New York. The sauna is the perfect centerpiece for small or large gatherings. A group sauna is different from a small intimate home sauna; it creates a unique social situation where you can commune with strangers and make new friends all while stripped bare of the trappings of social status, class, or superficiality. It can be a perfect setting for friends to solemnly celebrate life’s important moments: a reunion, a wedding, a men’s retreat, or whatever occasion that will be enhanced by closeness and shared exhilaration. The sauna easily holds a dozen or more bathers and is a stone’s throw from the lake.
As I always do, I tested the sauna before leaving a finished project. The new owner was elated as I brought it up to temperature and explained the intricacies of sauna; after a round, we jumped in the brisk lake. It was the perfect way to end an exhausting effort and make my long haul home a relaxing one.
If you are in Western New York and looking for a unique place to stay and want a sauna experience, I recommend you check outSilverlaken!
I get a lot of questions regarding sauna insulating details and thought I’d shed some light on a few issues. A caveat before I start: heat transfer science gets pretty complicated, and I am grossly simplifying things here. I’m not an engineer. I rely on experience and am constantly probing and measuring my own saunas to see what works.
A building inspector may want an engineer’s input, but just make sure the engineer understands what happens in a sauna.
If you are building an electric sauna, either in your house or as a stand-alone building, you’ll naturally want to insulate it for efficiency. Normally, builders (and building inspectors) think of R-value (printed on every insulation product label) as the golden metric, and the R-values of a wall assembly are typically added up to get a number that either complies with code or satisfies a self imposed trade-off between cost, efficiency, and practicality. R-value is the resistance to heat transfer. But it measures conduction and convection, not radiation, which is not much of a factor at lower temperature differentials. R-values are calculated with normal living spaces and long-term heat retention in mind, which in a typical home is calculated using an average temperature differential of 24°C (between heated and outside space). Since R= Delta T/QA, (where QA is the ability of the material to transfer heat), and in a hot sauna Delta T might be 100°C, the use of labeled R factors is totally skewed!
The second factor is time. Heat loss is measured in BTUs/hr. With the sauna only on for a few hours a week (bravo if it’s more!), your heat loss will be minimal, and hopefully, in the cold months it will contribute to heating the house. So, in terms of cost vs. efficiency, a lot of insulation may be overkill.
At the higher temps of the sauna, the radiant effect of heat is more of a factor, and the use of a radiant foil barrier comes into play. The heat you feel radiating from a wood stove is the long wave radiation. This radiation can move through common building materials, but foil stops it dead in it’s tracks. Anyone who has nestled under an emergency blanket or protected themself from the fiery radiation of a blast furnace (like when I pour bronze), understands the effectiveness of foil to bounce radiation back towards the heat source. But if the heat source contacts the foil layer, the aluminum superbly conducts the heat, defeating the purpose. So, when building a sauna, it is the radiant foil layer with an air gap on the hot side that is crucial to holding the heat in. This should be backed by as much standard insulation as is practical, but don’t worry about attaining super R-value. The exception being if the wall is an outside wall of the house and a part of the building envelope. In this case, R-value must be a minimum of what the rest of the house has. I prefer mineral wool, but in any case, do not use XPS or EPS foam directly behind the foil, as they will melt at sauna temps!
Vapor control in an interior sauna is really important especially, in modern tight houses. These structures tend to trap moisture. Vapor can cause damage that you can see, such as peeling paint, but also damage you won’t see, like moisture condensing in a wall cavity. A radiant-foil barrier, when carefully taped at the seams, is also a perfect vapor barrier. When I build interior saunas, I think about all of that moisture and imagine where it can get to and wreak havoc. I then seal off those spaces, and provide a vented path for moisture to escape.
Some enthusiastic löyly action will turn ladles of water into steam, which fills the sauna and then escapes into the house—like when you forget a kettle on the stove and all your windows fog up.
The best thing is to build your sauna next to a shower area and then vent that adjacent area with a decent bath fan to the outside or via the household HRV system. The sauna should also have an air intake under the heater, as per manufacturer’s instructions, and via a gap under the door so the sauna gets a healthy exchange of fresh air. Never connect the sauna directly to a mechanical ventilation system.
With careful planning of layout, insulation, ventilation, moisture control, and a heater that makes good löyly, your indoor electric sauna can feel like a wood burner on a pond’s edge and also be an integral part of your efficient home.
The stove, heater, or as the Finns call it, the kiuas is the heart of the sauna.
The role of the kiuas is to heat the room. But not like a wood stove, but by heating the sauna rocks, which in turn provide the heat and the löyly, or steam, that make a sauna what it is. In the savusauna, or smoke sauna, which arguably offers the most authentic experience, there is neither stove nor chimney. There is simply a pile of rocks made into a hearth. A fire is burned within (filling the room with smoke) until the rocks are hot. Once the fire is extinguished and the room cleared of smoke, the pile of rocks does its thing. Likewise, any sauna, whether it is wood fired or electric, is only ready when the rocks are hot.
When building a sauna, the choice of heater is important. But the rocks are even more important. A good heater will hold a hundred pounds, and thus, will make good löyly. A cheap heater will provide a few decorative stones, and you will feel like you are sitting in an electric oven. I have seen many well-designed saunas in my years and I have seen many poorly built saunas, as well. The worst use some variant of a cheap wood-burning stove with a dented pot of rubble or brick on top. In the best, the rocks are the focal point, and they get red-hot. Pick one up (with heat-resistant gloves, please) and drop it into a pot of water and you can make tea.
Left: Rocks shipped thousands of miles—only to explode in the sauna! Right: Cayuga Lake beach stones—can you spot the erratics?
The type of rock is critical: they should be igneous in origin, formed deep in the hot earth or in the furnace of a volcano. Think of these rocks as heat loving. Granite, grabbro, and basalt are typical examples. The Finnish and Swedish units might use grey peridotite. Then there is shape: smooth and round potato shaped rocks or jagged and broken pieces. I prefer the smoother rocks, but there is argument for using the jagged (more surface area). You can order a box of the latter from Tylö that will come all the way from Sweden. Once I opened a box to find a nice hand-written note from the fellow who packed them. Another heater company sent me a box from their supplier in Central America. Apparently, they needed a geology lesson. The polished siltstone rocks, once heated, started exploding! If you don’t want to have a box of rocks shipped half way around the world or risk getting impaled by rock shards, you can find your own.
Unfortunately, our local stone, meaning the rock that is cemented to the landscape here in Central New York, makes horrible sauna rocks. It is all sedimentary: shale, limestone and sandstone. Born in the bottom of ancient oceans, these rocks do not love fire and will complain by exploding if thrown into one. By the way, baptism by fire is a good way to test your rocks if geology eludes you—a good rock will happily glow red-hot. Thankfully, the glaciers that plowed through here brought with them piles of stone from places north that serve the sauna well. These are glacial erratics. As the glaciers retreated and melted, these stones were left behind. The resulting floods that carved our landscape left piles of these smoothed rocks (mixed in with plenty of local stone) in deltas, drumlins or moraines. I find them in the local gravel pit, which mines an ancient delta, or along the lake at my favorite park (another delta) when the water is low. Sometimes I take milk crates with me when I travel through the Adirondacks and fill them with potato-sized anorthosite rocks—which is what the moon is made of—and other pretty granites.
More important than the geology is the significance of the rocks. A Finn, even if they are using a heater with rocks packed in Sweden, will add a spirit stone or two: stones that come from home or some other special place. Stones all have distinct place markers and are borne of this earth and tied to a particular landscape. Except erratics. These have been swept from their homes in a geologic diaspora and found new homes as immigrants, oddities, and beautiful accents against the dull grey of the indigenous rocks. Even though I am made of local stone, coming from generations of Central New Yorkers, I have always related to the erratics: the outsiders, the immigrants, the atypical people. They bring us diversity, new culture and traditions like the sauna. In my next sauna, you will certainly find plenty of erractics.
Redhot Adirondack rocks / My Lämpimämpi stove / Stove wall faced with local field stone including shale.
The one thing that always comes up when people ask me questions about building saunas is “How do you insulate it?”. Intuitively, one might think that the sauna, with it’s high temperatures, would need more insulation than a house and should be as tight as possible to conserve energy. In fact, I’ve had building inspectors give me a confused list of requirements using such logic. The reality is that a sauna is such a different beast than a living space that most energy efficiency related calculations have to be thrown out the window. R-value, the number printed on most insulation products, is the resistance to heat flow of a given material of a given thickness for a given temperature difference (delta T) between the hot and cold side of the material. Typically, in our region, delta T is assumed to be 35° F, but in a sauna, the delta T might be 165°! So, in terms of heat loss, we get some very different calculations. To really understand R-value, you need to think in terms of it’s inverse: the U-value, or coefficient of heat transmission. U-value is expressed in units of Btu/hr/sq. ft./°F, or, plainly, how much heat is lost per square foot for every 1° temperature difference. A typical sauna, with R-13 average insulation, might lose 4000 Btus per hour (or 1200 watts). But, a typical sauna stove generates 25-40,000 Btus of heat per hour, so losing 4000 Btus is not a big deal. (It is more important if you use an electric heater: an 8 kw unit can only put out about 20,000 Btus an hour.) The other factor to consider is that, unlike a living space, you are not trying to hold the heat for very long. So, you don’t need to stack up piles of insulation in the walls and ceiling. In fact, many old saunas had no insulation at all.
What R-factor does not measure, though, is radiant heat flow. Radiant heat is like the sun warming your face; it is the short wave radiation that you feel. At higher temperatures, short wave radiation becomes a bigger factor than convection. To contain that radiant heat, we use foil (think thermos bottle or emergency blanket), but foil, being highly conductive, only works if there is an air space between it and the heat source. The foil doesn’t have to be visible to work; it can be buried between other layers of materials. In my saunas, it is behind the cedar, with an air gap between.
Saunas are also not meant to be tight, stuffy boxes. They require airflow to move the heated air and steam and to make them comfortable. The old sauna at Podunk was the best one around because it was old and drafty and it always smelled fresh. Counter to today’s high-tech homes, ventilation has to be designed into the sauna room to let it breath passively. The trick is to do it without creating annoying drafts.
When you sit on the bench and enjoy the relaxing warmth of the sauna, you probably aren’t running all of these calculations through your head—and neither am I! What I do know, from forty years of sauna experience, is what does and doesn’t work. Mostly, you want a good pile of rocks (kiuaskivet) that are hot enough to alternately bask you in their radiant heat and make good steam (löyly) and convective heat off the heater (kiuas) to produce waves of heat that gently wash over you as you breathe in the fresh aroma of the sauna. You want air, some light, and a feeling of openness and connection to the outdoors. It’s not so much science as it is art or perhaps a melding of the two.
If you do have specific questions about designing your own sauna, feel free to give me a call or email. Or better, have me come over for a consult. If you live far away, I can do one-hour phone consults. In my sauna building classes I talk about all the science and art of saunas in greater detail.
Recently, I was visiting my good friend Daniel, in Eugene, OR, and had the fortune of being able to help him put the final touches on the sauna he has been building in the backyard of his urban utopia. He moved there seventeen years ago from Ithaca, leaving behind the sauna on the family homestead in Podunk, just outside of Ithaca (yes, that really is the name of the hamlet). That little weathered building was where I was indoctrinated in the way of the sauna; it was the catalyst behind my sauna building career. As was typical with the Finns, Willie Uitti (the property’s first chicken farmer owner) built the sauna at Podunk was built first and it served as rudimentary shelter while the house was being built. Daniel has had to dream for the past seventeen years before he was able to build his sauna.
We worked together for a day and a half installing the heater, hanging the door, and getting it ready. Needless to say, the first firing of the new sauna was nothing short of perfect. It reached a good temperature, it made good löyly, the reclaimed cedar boards gave off a rich odor, and most importantly, it reached down to the pit of our sauna loving souls and transported us back to that cherished time and place on the banks of Taughannock Creek.
To the Finns, Sauna is not just a building or the simple act of sitting in a hot room, it is a quotidian ritual, a centuries old tradition, and a centering of one’s soul. The beautifully funky little shed behind Daniel’s house isn’t just a man shack, it is his identity. My role in helping was more midwife than carpenter, the honor of sharing the first sauna more like best man.
So it goes in the sauna building business, I don’t just make little buildings for people, I help them hold onto their identity, their heritage, and their dreams. It’s an honor and a privilege—and always a joy to share that special excitement of the first heating.
Podunk aficionados will recognize this bell that used to hang by the old sauna. Traditionally, the bell was used to alert bathers that a round was over or that the sauna was hot or that someone was approaching from the outside world.
The electric heater, although a far cry from wood, can still give off a nice glow. If installed correctly, it will provide plenty of heat and good löyly.
The inside as it should be: simple and dimly lit. The heat should be felt and almost seen as a shimmering veil that falls over the stress of daily life. Detailing here is clean and rustic, newly built but as old as the tradition of sauna.
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Looking back on recent sauna projects, I see a shifting trend in color choices made by my clients: from authentic dark-brown Viking tar to blue-grey, then brighter reds and blues and greens, and now this latest color feast. There is also a trend in current design to use more bright colors such as on the eye-popping florescent orange running shoes I saw in the gym yesterday. I have been following the designer Ingrid Fetell Lee. She writes about creating joy with color in her book The Aesthetics of Joy. She is persuasive about using more color for the simple reason that it creates joy. Although I teach color theory, I have a tendency to stick to blacks, grays, and low intensity colors in my art, a trend that I have been trying to evolve out of. Perhaps I can take some cues from my clients and take some color risks in my own work. This latest sauna project actually makes me think of late Mondrian paintings such as Broadway Boogie Woogie in which he reduced his palette to the three primary colors and sought to use color as the basis for expression.
The one thing that always comes up when people ask me questions about building saunas is “How do you insulate it?”. Intuitively, one might think that the sauna, with it’s high temperatures, would need more insulation than a house and should be as tight as possible to conserve energy. In fact, I’ve had building inspectors give me a confused list of requirements using such logic. The reality is that a sauna is such a different beast than a living space that most energy efficiency related calculations have to be thrown out the window. R-value, the number printed on most insulation products, is the resistance to heat flow of a given material of a given thickness for a given temperature difference (delta T) between the hot and cold side of the material. Typically, in our region, delta T is assumed to be 35° F, but in a sauna, the delta T might be 165°! So, in terms of heat loss, we get some very different calculations. To really understand R-value, you need to think in terms of it’s inverse: the U-value, or coefficient of heat transmission. U-value is expressed in units of Btu/hr/sq. ft./°F, or, plainly, how much heat is lost per square foot for every 1° temperature difference. A typical sauna, with R-13 average insulation, might lose 4000 Btus per hour (or 1200 watts). But, a typical sauna stove generates 25-40,000 Btus of heat per hour, so losing 4000 Btus is not a big deal. (It is more important if you use an electric heater: an 8 kw unit can only put out about 20,000 Btus an hour.) The other factor to consider is that, unlike a living space, you are not trying to hold the heat for very long. So, you don’t need to stack up piles of insulation in the walls and ceiling. In fact, many old saunas had no insulation at all.
