It’s been a busy year at Rob Licht Custom Saunas, and as the holidays approach, it is a good time to look back at everything that’s been accomplished and the hurdles we’ve gotten over and to be thankful for the blessings we’ve received.
We started the year in the midst of the pandemic which made for some challenges. But mostly, the pandemic has meant a huge uptick in the sauna business, as we all became more centered on home life and more reluctant to go out into public for things like gyms and saunas. Besides the several projects I have completed locally and around central New York, I have fielded calls and emails from folks desperate to have their own saunas from as far away as Europe and Australia. I never set out to become a sauna expert, but here I am, twenty-five years into making them, and people are seeking out my knowledge from all over. In the process, I feel like I have made many new friends. The global sauna community is alive and well. At the same time, due to the pandemic, I have mostly refrained from seeing all but my closest friends and family. It’s a strange new world, but I am thankful to be connecting to so many people, if only on Zoom.
For my new friends, I have designed and consulted on saunas from Maine to California—this has kept me busy when I was not getting my hands dirty. But whenever I can, I work with my hands, either in my 3000 sq. ft. shop, which I am ever grateful for, or on job sites. It used to be that builders would simply stop in the winter and spend the dark months sitting around the woodstove reading back issues of Fine Homebuilding, but now we all seem to be out there in any weather. My cut off is 10° F, any colder and I want to be by a fire—in the sauna, preferably. Good gear helps with the cold; I’m especially grateful for my boot warmer and insulated pants.
Mobile saunas showcased in the shop. Lansing, NY
Nothing I do is cookie cutter—I would die of boredom is life was too easy— thus the custom in my business moniker.
This year I seemed to run the gamut of sauna permutations: First, a garage retrofit for a yoga and sauna retreat, then a quiet walkout basement electric affair, then a classic one room wood burning sauna on an idyllic creek, then a more urban collaboration in Syracuse, followed by a tiny personal electric sauna in a bathroom, a rustic elegant wood-burning retreat in the trees, and a distance job downstate. Currently, I’m finishing up an electric sauna in a historic boathouse on Cayuga Lake. I’m hoping to take it for a test drive, with a jump in the frigid water, by Christmas.
Garage retrofit for hot yoga and sauna.Classic creekside sauna set fifty feet from swimming hole. Idyllic.Walkout basement electric sauna bliss.Backyard sauna design, urban collaboration in Syracuse, NY.Rustic, elegant wood burning sauna.Cozy interior of a backyard sauna.
Between all of these, I have sold a few of my Lämpimämpi sauna stoves and many sauna plans. Do It Yourself interest, in the mobile saunas is really big now. I get a kick out of seeing my designs being brought to life by many different hands. It is also fun to see all of the other builders following in my steps. The more builders, the better. There is plenty of work to go around, and I encourage anyone who wants to take the work seriously to pursue it with a passion. I did offer a sauna building class this year but had to cancel; Covid has thrown a wrench into a lot of plans. But stay tuned: perhaps 2022 will be the year.
Covid also tossed a wrench into the supply chain. We’ve all heard the phrase “supply chain disruption” by now. I bid jobs in the beginning of the year only to see prices on materials I quoted go up by 250%. Some materials simply vanished from the shelves. But now things have settled down, and I’ve started ordering and stock piling materials well in advance. I can keep several saunas worth of lumber and supplies in my big shop and insulate myself from some of the inflation—another reason to be grateful for the big work space.
Rob at the shop!
I’ve been working alone for most of the year, which actually suits me fine, especially with Covid lurking. Workers are hard to come by: not only are the skilled trades losing new blood, but I think the pandemic relief made a lot of people lazy and unwilling to get off the couch. Scarlet, now my partner in everything, has been my greatest blessing. When she can escape childcare duties, she has proven to be the hardest worker I could wish for. I could use a few more workers like her: eager to learn, unafraid of dust and dirt, and willing to sweat. She also manages all of the marketing, so give her kudos for the quality web media you see. The business feels like it wants to grow, so if anyone is seriously interested in building saunas and wants to relocate to Ithaca, drop me a line.
For those of you lucky enough to have a sauna, I hope you get to celebrate the New Year in it, for there is no better way to bring in the new and shake out the old. It’s been my tradition for four decades now, and I hope to continue for four more.
Taking sauna with Scarlet by the lake, December 2021.
Lately, I have been thinking about the application of the foil I use in my saunas as a radiant vapor barrier. Perhaps this is because it is almost Christmas, and I was thinking of how my family decorated the tree each year. The final touch would be to drape foil tinsel over everything; our mother would have to constantly damp down our enthusiasm by reminding us to place it carefully on each branch, not to throw it.
This suspicious sauna foil is aluminum-coated plastic—upper working temperature of only 131-248° F (55-120° C). This product compares to the ubiquitous foil “bubblewrap” people and is not to be used inside your sauna walls.
There are tricks to using radiant vapor barrier foil, but the first and most important step is to buy the right stuff. Like the tinsel we put on the tree, the foil may actually be aluminum-coated plastic—which you don’t want to use. That plastic is likely polyethylene, which, if you look it up on the material specification sheet that every product has, has an upper working temperature of 131-248° F (55-120° C), meaning it will likely melt at typical sauna temps. Sauna Foil, available from any of the familiar sauna suppliers, is aluminum foil on a kraft paper backing. I used to find it with fiberglass reinforcing thread, which is helpful because the stuff tears easily. Four foot rolls, rather than three foot are helpful so you can do a wall in two passes, but I have trouble finding that width.
I recently tried a new supplier selling four foot rolls of sauna foil, but upon opening, it had a suspicious plastic look to it. That night, I put it in the sauna and within seconds it began to distort and curl up like the polyethylene I suspected it was made of. (see illustration above)
The second trick is to design the wall correctly. I read and see a lot of misinformation that touts using no air gap with foil. This is wrong. The air gap is essential. The foil works by reflecting radiant heat. All black bodies1 give off and absorb radiant heat that travels in a straight line from one hotter object to another cooler one; the hotter the body, the more heat it emits. The sauna rocks radiate a soft heat to you, the walls, and the benches, and that is why you want the sauna to be laid out so that everyone has a view of the rocks. The fire, if seen through a clear glass door, also radiates heat but at a higher intensity—too high for a comfortable sauna (but great for ambiance). With an air gap of at least a half inch, when the heat hits foil, it is reflected back into the room or the backside of the cedar. Because the foil is also a perfect conductor, if it touches the back side of the cedar (as will happen with no air gap), it pulls heat away from the cedar and transfers it to the wall space behind the foil air gap.
Air gap. A sauna building best practice.
I’ve understood this thermodynamic principle for a long time. I took a class called Solar Design and the Energy Efficient Home in my first semester of college. We learned all about insulation, heat transfer, and basic building skills. The first day of lab, wherein we built a timber frame house, I was handed a Makita 12” circular saw. My building career started right then and there.
With the web of misinformation out there, I had to think of a way to illustrate this basic principle of thermodynamics. So, one slow day in the shop, I rigged up an experiment and photographed it (see illustration below). I set up a section of cedar wall about 18″ from my infrared shop heater and fastened two pieces of foil to the back, one with a 3/4″ air gap, and one with no gap. After an hour the cedar was 250° F on the front—like it often is in my sauna. The back of the cedar was 121° F, which is impressive by itself. The back of the foil with no gap was 115° F, meaning it was acting as a perfect conductor, and the back of the foil with an air gap was 71° F: room temp. The air gap was clearly making a difference, 45° in this case.
The thermodynamic experiment begins.after an hour on cedar.back of cedar.back of foil, no gap.air gap makes a big difference!
The foil is a perfect vapor barrier, rated at zero perms—meaning no vapor moves through it. But unless you layer it properly, with insulation behind it, the moisture will condense on it or the first cold surface it hits. Even in a perfect build, there might be cold spots in the insulation (typically about the size of a mouse hole), so there likely will be some condensation, but this is not a problem if there is air movement. The air gap behind the cedar allows air to circulate around the cedar, removing any moisture, and ensuring that the wood heats and dries evenly and remains stable. Heating one side of a board and wetting or cooling the other is how you make curved boat staves.
There are other tricks to using the foil: unrolling it and rerolling it foil-in, using temporary magnets when working a commercial job with metal studs. But the key is to use care. Use plenty of hi-temp foil tape and patch tears as you go and work with a partner if possible.
I suppose you could build a sauna by putting a heater in a refrigerator box, but that would last about a day and be incredibly wasteful. Cedar touching foil won’t ruin your sauna and neither will plastic melting in the walls where you don’t see it. But if you are going to take the time and bear the expense of building a sauna, you might as well do it and so it will last generations. I guess my mother was right: applying foil carefully and not just throwing it up is the way to work.
Building a sauna requires many skills. Basically, it is a small house. There are windows and doors, a roof and a foundation, framing, sheathing, subflooring, and the like. It also requires a design, and in many cases a permit, which will include drawings such as a site plan that shows required set backs and orientation. All of this I can do—from plans and permit applications to foundation to chimney. I pride myself on being able to do it all and on being as comfortable holding a drafting pencil (yes, I do drawings old-school) as I am a pick axe or nail gun. But the truth is, sometimes it is better to let others do the work they do best, so I can focus on what I do best, which is design and build saunas.
Recently, I had a job where distance made it much more efficient for the owners to use a local contractor to build the shell while I did only the sauna interior and the overall design. It turned out that Tim and his crew were much more adept than me at not only building the shell but carefully replicating the trim details of the one hundred fifty year-old adjacent main house. By the time I got to the job site, the interior was ready for my sauna work.
Just like many other types of projects during the pandemic, planning sessions on this job happened on the web or via text; we only actually all met once. Despite that, or maybe because of it, we weren’t in each other’s hair (a sauna is, after all, a very small space). Things flowed very smoothly once we got over the scheduling speed bump caused by the pandemic-induced supply chain upheaval.
The sauna sits perfectly between the historical architecture of the house and the modern look of a contemporary sauna. It was a team effort that paid off.
Increasingly, I hear from clients who want a 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 hot 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 was critical as to prevent moist air from hitting the cold cinder blocks and condensing. Next, 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; dramatic deep window recesses were 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 was fitted with traditional duck boards. LED lighting added just the right ambiance. The heart of this sauna is the Harvia Cilindro heater with it’s two hundred 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.
A sanctuary just a step away from home.
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!
Operable vent with slider doorFloating Bench, Hot Yoga Studio
A lot of building science is pretty theoretical. 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. I’m talking 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 proper 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 inexplicably filled 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 to 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.
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 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 was still shiny!
There was some hi-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 verified my disdain of fiberglass-type materials (rodents love it).
Polyisocyanurate board, original state.Fiberfax mouse nest.Melted EXP (expanded polysytrene) foam. Do not use!
On my desk, I have a piece of expanded polysytrene foam (EXP) 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.
You ask how or why electric mobile sauna? There are a number of reasons why going mobile makes sense, especially if you rent. No permits or special permissions are needed. You just park it in your yard and use it. You can take it with you on vacations or just for a Saturday down by the lake; you can even enter it in a parade. But why electric? Electric is no longer the inefficient dark horse of the energy world that it once was. It can be generated cleanly by wind or solar and is cheaper, cleaner, and easier to use than gas or oil. Although any purist will tell you a wood-burning sauna is the real deal, in some places, wood is not so easy—firewood may be hard to come by and difficult to store, and your neighbors may be too close for comfort or offended by the occasional whiff of smoke. Since I’ve eliminated gas burners from my repertoire (for reasons I won’t go into here), an electric mobile sauna is the next best thing. All you need is a place to plug it in.
When clients ask me to create a sauna, they often push me to do things I might have never considered doing. I’ve gotten requests to make saunas in spaces I thought were too tiny, on trailers, deep in the woods next to a pond, or to convert a cheap shed or laundry room. The most recent project to leave the shop is an electric mobile sauna. The owner has a Tesla electric car, so an electric sauna just seemed to make sense. The colors were more of an emotional choice: I painted it Sea Reflections blue like the ocean, where she likes to swim all year, with a Bonfire Red door to beckon her into the warmth of its interior and Vanilla Ice Cream trim because, well, who doesn’t like ice cream, especially after a sauna?
The how is simple: an 8 KW heater with a standard RV type hook up and a fifty-foot, very-heavy extension cord that connects to a standard car charging port (or special outdoor outlet). This will also work in many campgrounds with RV hookups. In a pinch, it can also be run off an 8500-watt generator.
This sauna also has a solar-powered low-voltage lighting system, just so there can always be light and because low-voltage systems are safer and more versatile than 120-volt lighting. I’ve been using these in some mobile wood burners and freestanding units. The neat little solar panel is a conversation starter; people are suddenly aware that the unit is more than a fancy tool shed trailer. When I tell them it’s an electric sauna, the little 25-watt solar panel gets a second glance.
I envision a fully solar electric sauna next (but probably won’t consider doing unless a client pushes me). It would have to use Tesla’s 270-pound Powerwall home battery, which has an 8kw output capacity. I imagine the entire sauna roof would a have to be a solar panel, but I haven’t done the engineering on this. This would not be cheap, but if someone out there who wants to be the first…. give me a call.
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.
