When building a sauna the first and possibly most important consideration is the location. With a wood-burning sauna, which is free from the tether of an electrical connection, it can be away from the house—not just for safety but also to create a separation from the electrical buzz of modern life. Simple and inexpensive solar options make it easy to provide needed lighting. It should have some of the comfort of home but be integrated into nature; near a body of water is always a good choice.
My latest sauna does all of that and more. The site is fairly close to the house but lies outside the garden gates. It all but hangs on the edge of a small gorge that contains a lively creek in its serpentine confines. Like the basswood and cherry trees that cling to the sides of the gorge, firmly rooted in the ground, the sauna is anchored to the 300 million year old shale bedrock with concrete and steel. The owners built a steep stair down to where small waterfall flows into a perfect bathtub sized hole. Descending it may be slightly perilous but that only adds to the adrenaline to rushing from the steaming of the sauna and plunging in the ever-cold water.
As I build I tweak my design to allow nature into the sauna. Framed and without sheathing I could see the perfect view up the ravine from the upper bench, suggesting the optimum location for a small candle window. The large window allows a view of the wooded hill and brings in ample afternoon light and the view down into the creek through the framing allowed me to imagine the possibility of a small square creek view porthole below knee level that would let in the ambient sound of the rushing creek. Exiting the sauna one faces the woods, not the house; a crude stair-path leads the eye up into the forest while the other leads to the creek.
The sauna is visible from the road and the house, but neither is evident from the sanctuary within. All you hear is the babble of the creek and all you feel is the relaxing heat of the sauna. Finishing a few rounds in the sauna with a dunk in the massaging water is pure bliss.
The site not only perfect for the sauna but it was a joy to work there, listening to and watching the water flow. Daily I took dips in the creek to beat the steamy summer heat. Having a site that allows me to enjoy the process of building lends means I can build a better sauna—one that is infused with the spirit of the place and connected to nature.
Increasingly I hear from clients who want their sauna as a way to enhance their hot yoga (Bikram) practice. It’s a perfect pairing: what better way to follow up (or warm up for) a yoga session than with an even hotter sauna!
Recently a couple asked me to convert an old dingy freestanding cinder block garage into a sauna/ hot yoga studio. First I made sure the cinderblock wall was stable and did some minimal repairs. Then I isolated the block wall from the warm, humid space by adhering expanded polystyrene (XPS) foam board to the walls. This is critical as it prevents moist air from hitting the cold cinder blocks and condensing. Then I framed in the space, insulated the walls with mineral wool batts and finished the yoga space with drywall and the sauna with cedar (with the requisite radiant sauna foil layer and air gap). New windows replaced the old; the dramatic deep window recesses a result of the thick walls. Bamboo flooring over floating sleepers over foam board created just the right bounce for the yoga space, while the sauna has traditional duck boards. LED lighting added just the right ambiance. The heart of the sauna is the Harvia Cilindro heater with it’s 200 pound rock capacity. Amazingly, the old building was plumb and square— the original masons did a good job. Fighting an out-of-square space is the bane of all renovators.
This project was a complete transformation for this building (see below), turning it from a creaky old, under-utilized garage into a revitalized space for self-transformation. Make an inventory of the neglected spaces on your property awaiting transformation and give me a call!
You’ve probably heard that I’ve spent a lot of time in the sauna but another hot spot I’ve spent a lot of time around is kilns. Specifically foundry kilns and ceramic kilns. Unsurprisingly there is a strong relationship between the two as they both involve getting things hot. In the lost wax casting process, investment or ceramic shell molds are heated to roughly 1500° F, which burns off the wax original- thus the “lost wax” of lost wax casting. This can take hours or even days depending on the mold type and size. A ceramic kiln can get much hotter- up to 3000° F. That is hot enough to melt steel and many other metals.
I learned how to do bronze casting in Art School. It is an ancient process and we did it pretty much the same way that it was done thousands of year ago. We learned to figure how hot things were by using our senses. All objects emit radiation when heated but at about 1100-1300° it become visible. Peering into a hot kiln (safety glasses strongly suggested) is like looking at another world, perhaps on some alien gaseous planet. Solid objects look like they are transparent. Heat and light become the same thing, the heated molds don’t reflect light but emit light. The blast of heat through the spy-hole is like a ray gun. We rarely used pyrometers (hi temp thermometers) and when we did it was only to affirm what our senses were telling us. We would record the smells of things burning off. When the smells were gone, the molds were clean and ready to accept the molten bronze.
When loading the kiln there is always discussion about the hot spots- certain delicate molds need to avoid the heat while larger molds might need it more. There is always conjecture about how the heat circulates; a whole aspect of kiln building is dedicated to controlling the flow of heat within the kiln. Some of this conjecture is borne out in the results of a firing—whether things fire correctly or not. Ceramicist use cones: small tapering forms that bend at specific temperatures. After a firing these will give a true telling of how the firing went. But, despite the science, there is still a lot of mystery and art to the process, so much so that a firing of a large kiln can take on a ritualistic feeling. Staying up late to tend the kiln, as is done with wood fired and other non-automated kilns, drinking beer and heating up pizza on the kiln, tends to add to the aura.
Thinking of all of this makes me think of sauna. Both have been done pretty the same way for millennia with an aura of ritual and involving community. Both have a focus on fire and heat, and, as well studied and commonly practiced as they both are, there is still a bit of mystery involved in each.
A kiln is like a sauna on steroids. The heat is so amplified that its flow and effects are unmistakable. Observing one is a lesson in thermodynamics. In the sauna building culture there is a lot of banter about how to best heat, insulate, and vent a sauna, yet all of it is conjecture based on theory until one sits in a sauna and feels the heat radiating off of the rocks and the wave of löyly hitting you on the sensitive tops of your ears.
When I design a sauna I draw from my years of kiln experience; I think of the heat as visceral substance, almost visible, as in a kiln. I relish the use of my senses to discern quality rather than depending on technology. Even if the sauna is electric with a digital control panel I rely on feel, not the number on the display. I imagine the flow of heat like the way it flows in a kiln. My foundry experience has informed my understanding of sauna in ways that are hard to describe but suffice it say that I have always been drawn to fire and to the mysteries that it holds.
COVID sure has made life strange and difficult for all of us. Patterns of living have been upended and new norms have emerged that will probably stay with us. One pattern that became very clear was that many people have decided to make their homes more livable, especially when it comes to outdoor spaces. Fortunately for me, this includes home saunas, which have seen a huge spike in demand which I am tying to keep up with. But, there has also been a huge increase in demand for materials associated with these types of projects causing me delays and headaches. Like the toilet paper that disappeared early in the pandemic, framing lumber, cedar, and pressure treated decking have all but vanished in some stores. Not only are people buying more for their home improvement projects but the triple whammy of last years wild fires, Covid taking out some of the workforce, and tariffs on Canadian lumber has caused major shortfalls and huge price increases in building supplies. Yesterday I bought a single sheet of OSB (oriented strand board— the most ubiquitous of building materials and the sheathing on virtually very house) and it cost me over $27—$20 more than what I paid 18 months ago. Everything else from 2×4’s to steel plate has doubled.
The contracting business depends a lot on giving a solid price well ahead of time so that the buyer can plan and budget. I’m working on projects I bid 6 months ago at prices I thought I could expect to pay when I got to the checkout. How can I give quotes when the prices are going up like that? Often, I have to eat those unexpected cost increases. Maybe the prices will fall, but I think, like wearing masks in grocery stores, we have hit a new norm.
I can’t absorb all this pricing mayhem so I’ll have to pass some of it on to you- my valued customer. If you are doing a DIY project and using a book written ten or more years ago, be sure to check prices; the big box stores do a pretty good job of posting it all online. And when you ask me how much something cost remember that cost, like time is a fleeting thing.
The most important thing to remember though is: how much is a sauna worth to you? It is measured not in dollars but in real value added to the quality of your life. In other words: priceless.
With over 30 years experience working in the building trade, Rob readily dispenses his knowledge to clients, a clear, professional communication style. If you need in-depth information on how to build your own sauna or need drawings/plans whether you are a builder, DIY builder or architectural firm I offer plans and consults. BOOK A CONSULT HERE >
Candle windows hark back to my time at Podunk where the light in the sauna came from a bare bulb in a porcelain fixture outside a little square window into the dressing room. The sauna i s too hot for a standard light fixture, so this arrangement made sense. Later, after I started building saunas, I learned that this was a more modern incarnation of the original candle window, which was literally a window into the dressing room with a shelf for a candle to sit on. These are common in Finland in freestanding saunas away from the house. The window allows for a special kind of spiritual, summoning light into the sauna. Especially on those dark winter nights.
In the sauna tradition, we slow down. The flickering candle light seen from the bench in the sauna, lures you to relax and reflect. Life and relativity. Could there be a more tranquil way to release the stresses of the day?
Although it is this quality of the light that is so important, the candle is totally pragmatic in a very Finnish way. A candle in the sauna room would melt even if not lit, so this was an obvious solution to the problem of lighting the dark interior of the hot room. Despite its pragmatic origins, I find it is also a chance for a little expressive design: it can be round or square, arched or colored. It can have an organic flare to it. Now, with cheap, battery-operated, multi colored LED lights and even fake candles that look real, the light can be more than a simple bulb on a pull-chain porcelain fixture, and be safe. Even if the sauna has built-in electric lighting, the candle window can be a signature element, one that distinguishes a personalized custom sauna from a generic kit.
It’s in the details.
Finnish pragmatic design inspiration comes from making use of what is available at hand and letting that material influence your design. There are many places to incorporate little details and personal touches: stick hardware towel pegs, stone faced stove wall with stones from your backyard, thresholds of locally cut locust, round windows, etc. Think of decorative elements you can hang above the mantle. In my sauna building plans you can purchase and download, there is more about windows, framing information as well as tips on using windows safely in mobile saunas.
wood burning sauna with candle window to dressing room
Here is a collection of the candle window design and builds over the years in and around the Finger Lakes and New York State.
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A lot of building science is pretty theoretical because, no matter how much research you do, at the end of the job most of the work is hidden in the walls. Unless you come back to do renovations, or worse, get a dreaded “call back” for something gone seriously wrong, you rarely get the opportunity to see how your work performs. I am not talking about cosmetic details like nail holes that don’t get filled or rough edges that didn’t get sanded, but about how well materials hold up to the heat or how well you have managed moisture movement through the walls, either as precipitation working its way in, or the more mysterious way that water vapor works its way out. (or inwards in some climates). This moisture is driven by vapor pressure, which can drive water molecules through most any material given the right humidity and heat differentials— something a sauna has a lot of. I learned about vapor pressure when I realized that my hollow steel yard sculptures were inexplicably filling up with water. My welds are very solid and water-tight but somehow moisture was penetrating the steel, condensing and not getting out. Cutting holes in the bottoms to let trapped water out solved that problem. There’s a bit of molecular science involved here, but suffice it say that vapor pressure is very strong- strong enough that when I throw water on the hot rocks my sauna door pops open as if the löyly has scared a ghost out of hiding. (Read previous post about Insulating Saunas)
Thinking about all of this has left me wondering what is happening in my sauna walls; am I doing a good job? is the insulation holding up? is water getting trapped?
Yesterday I had to do some retrofitting on the first mobile sauna I built in 2013. I exchanged the Scandia gas heater for a wood burner and got to peer into the dark interior of the walls. This is a sauna that has seen heavy and very hot (200°+) usage. The walls were built with cedar inside and out with only a 1″ layer of foil faced polyioscyanurate foam board in between the studs.
Here is what I found:
There was no damage from trapped moisture and the foam board looked as good as new; the foil facing still shiny! There was some high-temp fiber fax insulation used around the gas heater; a rodent had gotten into this (despite my filling gaps around the gas line with steel wool) and made a stinky little nest.
So this confirmed my use of the polyisocyanurate board, which has a service temperature of 250°F and my disdain of fiberglass type materials (because rodents love it).
polyisocyanurate board, original state
fiberfax mouse nest
Melted EXP (expanded polysytrene) foam
On my desk I have a piece of EXP (expanded polysytrene) foam I pulled out of a failed sauna I was asked to repair. It looks like one of my steel sculptures from my Landform series – a flowing, green landscape (of melted plastic). Its service temp is listed as 150° F. All materials have material data sheets, usually available on the manufacturers web pages. I consult these whenever I am unsure about materials, especially given that the extremes of the sauna are like the extremes NASA engineers have to deal with. Clearly there is a correlation between science and reality, even if it is happening unseen inside the walls of your sauna. So when choosing materials, listen to the science, learn from observation and don’t just buy the cheapest materials or use only the easiest approach. Consult with the experts. Sometimes there is more to it than meets the eye.
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