A Sacred space in an old woodshed
On a river in Mount Hood National Forest, tucked in amongst the cedar and doug firs, sits a very small cabin. Nearby, an even smaller woodshed was moldering away, waiting.
I first began visiting the forests of the pacific Northwest 25 years ago, and ever since I have been continually drawn back. Sometimes I come seeking adventure, sometimes quiet, sometimes simply the feeling of awe that comes standing among the big trees.
Sometime later, I discovered the ritual and experience of sauna. I began seeking out sauna everywhere I went. Around each, I invariably found a community willing to step outside time together, to drop into the awareness of their bodies. With this awareness came also a heightened connection to the natural world — whether it was the fjord in the middle of Oslo, a remote beach in Ireland, or deep in the woods of British Columbia. It was only a matter of time before I began dreaming of creating such a space back home.
The project was a DIY build, done slowly over the course of nearly a year. It was done mostly alone, offering solitude and an outlet for the big feelings accompanying a difficult chapter of my life. However, it was conceived from the begining as a space for building and strengthening community. Many loved ones contributed. Family members helped swing hammers and operate unfamiliar saws. A close friend and veteran sauna-builder offered wisdom and encouragement. Another friend created a beautiful heat shield that became a central element of the design. A neighbor milled the cedar he felled nearby.
When I told people what I was up to, more than a few wanted to know more. Some were just curious, but many harbor similar dreams. It is my hope that this journal will help inspire and inform such dreamers. Create the space, gather the people, light the fire.
Design
The design of the sauna started with its most central elements — the hearth, and the natural view behind it. I wanted the entire focus of the room to be on these two elements, which meant determining where to place the windows and then working backwards from here.
Dividing the space
The existing structure is 10' x 12'. I divided this space into the hot room, a small changing area, and a storage space. The hot room is approximately 6' x 9'10", with 7'6" ceilings (8' ceilings would have been nice, if they had fit). The benches use an L-shaped layout — an upper bench at 42" and lower bench at 22". Two windows look out onto the forest and nearby river.
Stove selection
IKI stoves are renowned for their löyly thanks to their unique helical chimney and generous rock capacity. Another advantage of all that rock is that it reduces required fire clearance — allowing the stove to be tucked tight into the corner, right where I wanted it. However, the whole stove weighs almost a ton, which added some complexity to the structural work.
Benches
The benches are arranged in an L-shape, with 24" deep primary benches at the back of the sauna and a set of smaller smaller benches along the side wall. Adding side benches offers a bit of extra seating when there are guests.
Supporting a ton of rocks
Before building the sauna, the existing interior of the outbuilding had to be stripped down to the joists and studs. Everything inside needed to come out: a ton of old junk, an existing wall, and the floor — which was in rough shape. I evaluated and reinforced the existing framing where needed.
Demolition
I ripped out all the existing floor and then inspected every structural member for rot — especially at the sill plate and anywhere near the ground.
Leveling the joists
The floor was sagging badly due to undersized joists. I jacked everything back to level and added a beam to break up the 12' unsupported span. I also sistered the joists in the sauna area.
Supporting the stove
The IKI stove with a full load of stones weighs nearly 1,000 lbs, so I added joists to half the joist spacing under the stove location. I supported these with a new beam and 3 new piers, one on each corner.
Defining the room
I added the interior wall and door to the sauna room and dropped the ceiling to keep the heat in.
Framing partition walls
I built 2x4 stud walls at 16" on center. I added corner studs for the paneling — every inside corner needs a nailing surface.
Installing blocking
I added horizontal blocking between studs at the bench hanger heights. This blocking serves two purposes — it stiffens the walls, and it gave me more places to screw the bench hangers into. I changed my mind several times about the exact bench placement, so I was glad I added the blocking!
Framing rough openings
I framed in the door plus an opening for ventilation.
Dropping the ceiling
I nailed 2x6 joists to the rafters to create a dropped ceiling at 7'6". Again, every corner needs a board to nail the paneling!
Chimney placement
I should have figured out the chimney placement at this stage. It was a complex process, so I put it off. I had to determine exactly where the stove would sit, and that depended on heat shield and wall designs I hadn't finalized yet. The stove placement dictates where the pipe crosses through the the ceiling and roof. I also needed to select the exact components of my chimney system (this guide was helpful for that).
Because I put all this off, I had to move a ceiling joist later in the project to accommodate the stove pipe. Of course, I could have cheated with some bends in the pipe, but a straight run looks and drafts better.
Wall assembly & clearances
Because I wanted the stove tucked into the corner as far as possible, I first had to figure out my exact wall assembly thickness and fire clearances. I planned an air-gapped heat shield backed by cement board to reduce clearances. I had to consider the clearance requirements of component — the stove, the stove pipe, the chimney and any connectors or supports.
Placing the pipe
I made a full-size template of the stove with the exact dimensions, including the furnace and chimney pipe outlet. I placed it on the floor in the planned position, measured clearances off it, then dropped a plumb bob from the ceiling to find the exact center of the pipe. Now I knew where the pipe needed to pass through.
Framing the ceiling support box
Because the attic space was short, I determined the chimney would drop through the roof and be supported by a ceiling support box. This box carries the full weight of the chimney and maintains the required clearance to combustibles.
I framed a box in the ceiling slightly larger than the support box, centered on the pipe location I'd determined with the plumb bob. This is where doing it during the framing phase would have saved me — I ended up having to move a joist that was in the way.
Electrical
Before insulation, I installed circuits for the sauna wall light, a changing room light and outlet, outdoor lighting, and storage area power. I also installed a box for under-bench lighting, though I later scrapped that idea.
Running wire
I drilled through the middle of studs with a 3/4" bit, all at the same height for a clean run. I used 12/2 romex, with nail plates over every wire run through studs to protect wires from future nails and screws.
Installing boxes
I left 6" of wire in front of each box and stapled the cable within 6" of every box. One wire per slot in the back of each box, with the ground wire attached to the grounding screw on the metal boxes. I used metal boxes inside the hot room — plastic won't hold up to the heat.
I forgot to account for the full finished wall assembly thickness (paneling + strapping + vapor barrier) when mounting my light box, and it was a pain to fix later. The boxes need to be flush with the finished surface.
A simple, classic design
Gapped cedar deck boards are a traditional sauna construction method that offers built-in ventilation and drainage. They're a great fit for wood-fired saunas with plenty of heat and a need for air flow to feed the stove.
Installing hardware cloth
To keep rodents out, I stapled 1/4" galvanized hardware cloth between joists on the underside before laying any decking.
Planning the layout
I did the math to determine how many boards I needed and roughly how much I'd need to trim the last board. I started at the front of the sauna so the trimmed board would be hidden under the benches.
Installing the boards
To conceal the fasteners, I used the Marksman Pro system, which has the added benefit of ensuring consistent 3/16" spacing. The first board had to be face-screwed, but those were hidden by the wall assembly later.
A complex, classic(ish) design
The windows were a bit of a sticky wicket — they needed to be engineered to withstand a sauna (tempered glass with high-temperature silicone sealant is a must), but also wood-framed and classicly styled to meet federal historic preservation standards. What I ended up doing was simply using two windows in each opening — a sealed double-wall unit from One Day Glass on the inside; and a simple, traditional barn sash window on the outside. A "hot window" and a "cold window", if you will. This made the install more complex but was far cheaper than having someone make custom windows that meet all those requirements. To make things easier on myself, I left installing the "hot window" until after the paneling was complete.
Installation
Framing the rough opening
I built a temporary support for the eave-side wall before cutting out the existing studs. Then I framed in the windows and cut away the existing sheathing and siding. I installed some shingles on the sill plate to create a slope for drainage.
Flashing the rough opening
I applied flashing tape around the entire rough opening and about halfway into the framing — that material isn't rated for heat and I didn't want it to go beyond my outer window.
Installing the jambs
I build the jambs and sill from 1x6 doug fir. I sealed everything on the outside with exterior sealant
Installing exterior stops
I cut 1" × 1/2" exterior stops and primed/painted all sides before installation, cutting a small weep hole for drainage. I caulked each piece (leaving a gap for the weep hole) and then brad-nailed in place.
Setting the glass
I placed the sash in the RO and wedged interior stops against the glass with two beads of sealant — leaving a gap on the outer bead for drainage. This time I used a high-temperature silicone sealant — it's important not to use standard caulk anywhere that gets hot!
Retaining the heat
Insulation
I used rockwool insulation throughout. It's fire-resistant, moisture-tolerant, and handles extreme sauna temperatures without degrading. I installed R-15 (3-1/2" thick) in the walls and R-23 (5-1/2" thick) for the ceiling. Standard fiberglass insulation has lower R-values for a given thickness and is not rated for the high temperatures and moisture of a sauna.
Insulating the walls
I pressed R-15 batts into each stud bay, being careful not to compress them. I cut each piece to fit snugly around electrical boxes, blocking, and window framing. I stuffed small pieces of Rockwool around door and window rough openings and other gaps. Some use spray foam for gaps, but rodents love building their nests in this stuff and I avoid it at all costs.
Installing ceiling insulation
The R-23 batts went overhead, friction-fit between joists. Rockwool fibers is a lot more pleasant to work with than fiberglass, but glasses, gloves and a mask are still a good idea. Since most heat loss occurs through the ceiling, I laid extra R-23 batts on top of the joists in the attic area.
Vapor barrier
I took detailed photos of all stud and blocking locations at this point — I knew I'd need to find them later when installing bench hangers, trim, and accessories.
The vapor barrier reflects radiant heat back into the room and prevents moisture from reaching the insulation and framing. I was careful to create a continuous barrier, sealing any gap where moisture might penetrate and cause mold or rot. It was very helpful to have an extra set of hands for this process!
First run — horizontal around the room
We rolled a 4' wide strip of aluminum foil horizontally around the entire room, shiny side facing in, starting 1/2" from the door rough opening (the reveal gives the tape a landing spot). We stapled at every stud and used a scrap piece of paneling to crease the foil tight into corners.
Second run — up, over, and down
We ran the second pass vertically: up the wall, across the ceiling, and down the opposite wall, overlapping the first run by at least 6". We then repeated this process to cover the rest of the walls and ceiling. We rolled right over the windows.
Cutting & taping
We cut X-shapes at window openings, folded the flaps to the studs, and taped the seam with foil tape. We carefully taped all the overlaps in the barrier, and all the little cuts and mistakes we made installing it. The vapor barrier goes behind electrical boxes! We sealed around wires and box edges with more tape.
Finishing the walls
Mind the gap
Installing furring strips over the vapor barrier are not a critical component of sauna construction, but they are a good idea unless space is extremely limited. Furring creates an air gap, allowing moisture that condenses on the vapor barrier to run down the wall instead of eventually rotting the wood paneling. They also help eliminate irregularities in the framing to provide an even nailing surface for the cedar paneling. Finally, air gaps are insulators.
Installing wall strapping
I started with a single horizontal strip along the top of each wall, and then placed vertical furring strips on top of the wall studs. I nailed these in place with 2" stainless steel brads.
Installing ceiling strapping
I ran furring strips parallel to the ceiling joists. I used brads here too, but I reinforced them with a bunch of stainless steel screws. Here again, every corner needs something to nail the paneling into!
Adding blocking strapping
I added short pieces of strapping at bench blocking locations, around window and door openings, and anywhere trim or accessories would attach. By this point I knew more or less where my benches were going, so I avoided running strapping all the way across my blocking (since that would break up the drainage path in each stud bay).
After installing the strapping, I sprayed black high-temperature stove paint over the corners in my ceiling. I planned to have a small gap for air flow between the wall and ceiling, and didn't want the shiny foil glaring out in the corners.
Installing the heat shield backer
Before installing the paneling, I screwed 1/2" Durock (cement board) over the vapor barrier into studs in the entire stove corner, from floor to window height. There was no need to skim or paint this since it would all be covered by the heat shield.
The fun part
I used 1" Western Red Cedar T&G for my build. To save money (cedar is dear these days), I used about 75% TK (tight knot) grade, with a bit of clear cedar for the backrest areas behind the benches (knots can create hot spots that can be quite uncomfortable to sit against). I used 2" 18-gauge stainless steel brad nails.
This was one of the most satisfying parts of building the sauna. I enjoyed taking it slowly, obsessing over the selection of each board to create interesting patterns and working carefully so that there are no gaps that need to be covered with trim.
As I installed the paneling, I made pencil markings to indicate where the bench blocking was behind the wall.
Backs and sides first
Before starting a surface, I calculated my coverage so that I could rip first board width roughly the same as the last board. No one wants a wee skinny board at the end.
I started the walls on the window side wall, then the back walls, then the door wall last. Each board butts into the last, hiding the cut end, and the cut ends of the boards on the door wall are hidden under door trim. I worked bottom-up, 3-4 courses at a time around the entire room to keep board lines (and patterns!) aligned. When I got to the top, I left enough room for the ceiling boards plus a small gap. The last board is face-nailed. I also left very last board on the door side off to make it easier to sneak in the ceiling boards.
Window wall next
There is no universal rule to which surface to do first or last, and a lot depends on the space. In my case, I left this wall last because it had the most room to cheat - I could hide ends under both the door trim and window/heat shield. It also had a lot of short runs where I could use up leftovers. Again I left a couple boards off at the top until after the ceiling.
Ceiling last
The ceiling was last, but because I left off a few wall boards it was easy since I could hide the ends under the top course of the walls (yes I could have just done the ceiling first, but I wanted to be able to pick all the best boards for the walls!). I measured the ceiling at both ends every 3-5 boards to prevent "fanning".
I stopped the ceiling boards when I reached the stove pipe. Aftert it was installed (see next section), I finished up the ceiling and then snuck in those last wall boards. I went in the same wall order as before, ending at the front wall. This very last board was a full length course, and getting it in under the ceiling was tricky! I ended up needing to do several gradual cuts on the table saw with a slight bevel to get it to finally pop in.
The heart of the sauna
Installing the stove
Installing the stove was a complicated process I wish I had figured out earlier (see the section above on Chimney Placement). I ended up hiring a technician to do the actual chimney install — I was behind schedule and fire safety is not something to rush. There are many good guides out there for those who want to DIY.
After the chimney was installed, I finally installed those last few ceiling and wall boards.
I built a quick, hot fire in the stove outside the sauna before installing it, to burn off any residue from the manufacturing process.
One fall, I walked down to the river. The first thing I saw was a dead salmon staring back at me. It was lodged on a rock, its mouth agape and body torn. It had completely worn itself out. Then, in a quiet part of the river, I spotted a large, dancing shadow. Another salmon, catching his breath. As I watched, he resumed his swim up the river. The river was shallow here, and much of the fish's body was above the surface. I could see him clearly now, his body was taterred and his movements deliberate. He looked unfathomably tired, and not the least bit deterred.
In that moment, this fish's will spoke very deeply to me. I thought about my own struggles, which were as nothing to his. And yet nothing was wrong — he was doing exactly what he was supposed to do. I imagined my own journey up river. The struggles remained, but felt lighter. There was no agony, I was simply on my path.
In my head, this fish is forever swimming up the river. I turn to him often, and he never fails to move me.
Fabricating the heat shield
Given the central role of the stove corner, I knew I wanted something special for the heat shield. I also wanted to reduce the required clearance as far as possible. A friend of mine runs a metal fabrication business, so I commisioned him to design and fabricate a custom heat shield. Somehow, he managed to capture my feelings perfectly — the river and salmon in the design speak to me just as they did in the original encounter.
The system consists of 3 pieces - a sheet metal panel mounted with a 1" air gap in front of the cement board, the decorative layer mounted in front of it, and a steel plate for floor protection.
Ventilation
Besides staring deeply into the flames, one of my favorite things about a wood-fired sauna is that it brings a lot of air movement into the room. This creates an entirely different quality of heat. It feels like the heat washes over you. It has none of that stifling, stuffy feel common in electric saunas without proper ventilation.
The floor system provides plenty of fresh air for the stove, but it needs a place to go. To ensure air circulation across the entire sauna room, I placed a 6x8" outtake vent high on the back wall, opposite the stove.
Sealing the opening
I had already framed the opening with short headers. I sealed the entire opening with aluminum tape, and tacked a screen on the interior side to keep rodents out.
Protecting the vent
I made an angled rain hood out of some scraps of cedar. I mounted this on the exterior and sealed it with exterior caulk.
Controling air flow
I made a cedar vent cover from more scraps. It slides to allow adjusting airflow during use. Unlike using an electric sauna, I often keep the vent partially open during use. Counterintuitively, it often feels hotter this way!
A custom door
Cedar sauna doors cost well over $1,000. I'd never built a door, but determined I could build one for next to nothing, using leftover cedar scraps and a $35 double-wall window from One Day Glass. It was a lengthy process, but the result fits the space better than anything I could buy.
Building
The door consists of 1x2" cedar framing with lapped joints, covered on both sides by scrap T&G. I put in a vapor barrier on the hot room side, and insulated the frame cavities.
Cutting lap joints
I used a router to cut my laps, routing opposite stiles/rails together in pairs to ensure consistency.
Assembling the frame
Cedar absorbs a lot of glue. I applied a thin sealer coat of glue, waited 60 seconds for absorption, then applied normal glue and clamped.
Paneling the hot room side
Before installing the paneling I added a vapor barrier to the hot room side and taped off all the edges. Then I paneled the over this, taking extra care to match my pieces visually with those on the adjacent wall. I cut my paneling a bit long and lined up the edges on the hinge side with the ends hanging over a bit on the latch side. I planned to trim these off when I cut the bevel on the door.
Flipping and repeating
I flipped the door over and filled the frame cavities with leftover rockwool. Then I paneled over the other side and installed the window!
Hanging
Hanging a 75lb door could have been a nightmare, but with some careful prep it went smoothly. Having a friend helping for this part was critical!
I nearly put the hinge mortise on the wrong side of the door jamb — triple-check and mark it clearly before routing.
Beveling door edges & mortising hinges
We fed the entire door through the table saw to cut a 2-3° bevel on the latch side of the door, with the shorter side on the stop side so the leading edge clears. We then mortised and installed the hinges into the door, using 2" brass hinge screws. Because the door was so thick, we placed the hinges plates all the way into the side where the screws would bite into the frame. This meant we needed to do a bit of creative sanding on the surface of the door to accomidate the hinge barrels.
Building a jig for the jamb
We made a jig from 1x2 stock, cut to the height of the door plus 1/8" for the top reveal and 1/2" for the bottom. We lined up the jig to 1/8 above the top of the door and attached the hinges.
Cutting the jamb
First we cut the jambs to length, again including the door height plus a 1/8 reveal and a gap, but this time measuring off the actual floor. The floor sloped slightly, so we made the longer side jamb taller so the head jamb would sit level. We also added the stock width to the side jambs since I planned to use a lap joint. Then we routed a shallow lap joint — just enough to keep the visible joint tight.
Mortising & ripping the jamb
We clamped the jig to the side jamb (lined up with with the bottom of the lap joint) and transfered the hinge locations with a utility knife. We used a combination square to transfer the depth of the hinge plates from the door, then routed the mortises on the jamb. Finally, we ripped jamb stock to width, accounting for the full wall width. I was glad we did this last, as it allowed us to tweak the depth of the hinge mortises after they were cut.
Assembling & installing
We attached the hinge-side jamb to the door, then assembled the frame on a table using shims to provide 1/8" gap all around. Then we stood the assembly up in the opening and shimmed the top corners to hold it in place. We then opened the door and shimmed the hinge jamb to plumb. We then screwed the hinges into the jamb, filling any gaps behind the hinges with shims and using long hinge screws to penetrate into the framing (this is a heavy door!).
Finally, we closed the door and shimmed the latch jamb to ensure a consistent 1/8" gap , securing with long trim-head screws.
.jpeg)
.jpeg)
Measure once… then sauna
Lumber for the benches was locally sourced western red cedar, felled by a neighbor, who had already air-dried for two years before we milled it. I based the bench construction on this guide, with a few modifications.
Working backwards from my ceiling height, I knew I needed at least ~42" headroom at upper bench. This determined the height of my upper bench, and I worked down from there.
- Upper bench: 42" height, 24" deep on back wall, with a 18" L-extension
- Lower bench: 22" height, 24" deep with on the back wall, with a 12" L-extension. Both lower benches are tucked 4" under the upper bench.
- Hangers: The benches are supported by 2x4 hangers anchored into the wall.
Milling
We milled true 2x4s for the bench stock, carefully selecting clear sections to ensure there are no knots on the seating surface. The stock was still ~20% moisture content after milling, but I figured I could dry them the rest of the way in the sauna!
Bench hangers
Setting heights
I subtracted 4" (true 2x4 width) from the bench height for hanger positions, then carefully marked my anchor locations. I used 5" structural screws (1.5" hanger + 1 3/8" wall assembly + >=1.5" stud penetration), following the the screw pattern suggested by the manufacturer.
Installing side bars
I cut two side bars, the left one at 24" and right one the full length of the L bench. I cut decorative 45° bevels on the exposed ends of all side bar pieces. Then I fastened them into the side walls, checking level front to back and side-to-side.
Attaching the backwall hanger
I fastened the backwall hanger into studs following the same screw pattern, with additional 3" screws underneath and on the face at 45° to lock the backwall piece into each side piece.
Installing side support pieces
For additional support at the bench ends, I cut two more side pieces at 22.5" with matching 45° bevels. These were glued and fastened onto the existing side pieces with 3" screws.
Prototyping the benches
At this point I had upper hangers but my lumber was still drying and I wasn't sure about the exact height and placement for my lower benches. And I badly wanted to give this sauna a test run! I cut my milled lumber 1/4" shorter than the room width and placed them on the hangers with a scrap piece below to give the final bench height. Then I stacked some short lumber on the floor and laid more 2x4s across for the lower bench. I now had usable benches — and a drying rack for my lumber!
Bench construction
This section is a WIPSizing bench assemblies
I deducted 1/4" from room width so the bench wouldn't be too tight to install, and used pocket screws for the front fascia board — this hides all hardware from the visible face.
A long-awaited moment
After nearly a year of construction (and many years of dreaming and scheming), this was the moment the whole thing was building towards! But first, I needed to move 800 pounds of rocks…Placing the stones
With the stove installed and the prototype benches in place, it was time to load up the rocks. Despite my excitement, I took care, placing each stone carefully to cover the furnace and maintain air flow.
The first firing
The light was fading as I fed the fire and the sauna slowly got up to temperature. Just as it reached 190° a soft rain began to fall. Climbing up onto the benches for my first sweat, I was overwhelmed by my emotions — pride at what I'd built, gratitude for what I had, and even a bit of sadness for a long-held dreamt of project finally coming to its close. Plunging into the wintery river, I was already dreaming of the many moments others and I would surely share in this special space. As excited as I was to share it, it felt perfect to be alone and let these emotions wash over me with the icy waters and the gentle heat of the sauna.
.jpeg)
The final details
This section is a WIPLighting
After considering under bench lighting and a range of other options, I ended up choosing a very simple lighting system. I wanted the space to stay fairly dim and largely lit by firelight. A simple dimmable lamp was installed, with a beautiful cedar covering.
Trim
The final details — trim, door stops, fire safety equipment, and exterior work.
- Door window trim: 1-3/8" x 1/2" — from jamb rippings
- Door casing: 3" x 3/4" — two sides at 76-3/8", header at 31"
- Window trim: 2.5-3" wide — four sides at 32", two tops at 37"
Remaining items
- Door stop and magnetic latch
- "Hot window" installation and sealing. Same process as installing the "cold window", just different materials. Nothing gets painted, and everything has to be heat tolerant. I sealed the jamb with high-temperature aluminum tape and used high-temperature silicone sealant for my stops.
- Smoke/CO alarm and fire extinguisher
- Changing room – finishing work, lighting, bench, shelves and hooks
- Exterior: new door, reshingle around new windows, cover over old windows, re-flash eaves
Resources
This section is a WIP
Build guides
- Sauna Build, From Start to Finnish
- Art of Sauna Building
- Trumpkin's Notes on Building a Sauna
- How To With Lech (YouTube)