Thermally modified wood
A solid Nordic spruce shell brings the warmth and texture of real wood, with improved stability and decay resistance for outdoor use.
A sauna that brings people together.
The upper benches turn a corner, so conversation comes naturally. Stretch out on the 6 ft 6 in rear bench, sit with friends along the side, then take a breather on the porch. A glass front keeps the backyard in view.
Room to share the ritual
Warm up together, step outside to cool down, and come back for another round. The porch seats make those pauses part of the sauna, too.
The 4 ft 3.2 in side bench is shorter than the rear bench. It adds seating around the corner; it is not a second full-length reclining bench.
Thermory quality, board by board.
At Thermory’s plants in Estonia, every board is scanned and graded on the line, so only the best wood ends up in your sauna.
Thermal modification is a controlled process: heat and steam, with schedules matched to the wood species and sensors monitoring the kiln. It improves dimensional stability and decay resistance without chemical preservatives.
That is why the Thermory name matters to us. The material, the milling and the quality checks all contribute to how the kit goes together and how the wood handles repeated heat, moisture and outdoor weather.
Explore Thermory at Sauna Marketplace
Made for the backyard. Built with care.
The rain jacket is included
The fitted roof cover protects the top of the sauna in wet weather. Install its securing slats as the manual shows and keep the cover in good condition.
The details still matter
A level base, correctly fitted glass, ventilation, band tension and drying after use all matter. We help you plan the build and care for the sauna afterward.
One layout. Two views.
Choose your rear wall.
Both models have the glass front, porch and L-shaped benches. The difference is the rear wall.
#40: panoramic rear window
Choose it when the view behind the sauna deserves a seat, too. Glass at both ends makes the room feel open. Our Studio photo tour shows #40. The 3D model shows either version.
#41: solid wood rear wall
Choose it when the sauna backs onto a fence, neighboring yard or a view you would rather leave outside. You keep the glass front and the same seating, with privacy at the back.
See the choices before you choose.
These are views from our interactive 3D model. Use the product options above to select your sauna and heater; the viewer follows your choices.
3D previews show layout and equipment. The selected sauna and heater manuals govern installation, ventilation and clearances.
A proper bench beats a headcount.
Thermory lists seating for up to six. The rear upper bench is 6½ feet long, and the side bench turns the corner. You can sit facing each other instead of lining up shoulder to shoulder. Use the 3D interior view to look at the layout before choosing.
| Sauna footprint, including porch | 82.7″ wide × 98.8″ long |
|---|---|
| Height, including base beams | About 87.9″ |
| Rear upper bench | 78″ long × 19.5″ deep |
| Side upper bench | 51.2″ long × 19.3″ deep |
| Lower footrests | 60.5″ rear and 43.7″ side; 8.1″ deep |
| Floor grids | Two removable grids, 44.6″ wide × 43.3″ deep together |
| Interior bench wood | Thermo-Aspen |
| Shell | Thermally modified Nordic spruce; made in Estonia |
The measured photo in the gallery is our 2024 Square, whose floor grid is 48″ wide. Thermory’s current drawing shows 44.6″.
Leave room for the door swing, assembly, maintenance and the clearances required by your site.
Know what you are buying
The sauna is the start of the package.
Included with the sauna
- Thermo-Spruce shell, base beams and assembly hardware
- Glass front and hinged door; rear window on #40 or wood rear wall on #41
- Upper benches, lower footrests and backrests
- Front porch seats and floor grids
- Roof rain jacket and exhaust vent
Choose with your order
- HUUM HIVE Mini or HUUM CORE heater package
- Heater controls and required accessories, as listed in the selected package
- Optional under-bench lighting
The first price is the sauna alone, before the heater package and shipping. Build the package that suits you; the total updates in the buying section.
Plan at your site
- A firm, level base that supports all four base beams
- Freight access and a confirmed unloading plan
- Assembly help and space to work
- Electrical supply, wiring and installation by your electrician
The heater choice changes the session.
The HIVE Mini’s open stone basket is a good fit if you like pouring water over the stones and enjoying the heat from the upper bench. The CORE is a compact heater clad in Thermo-Aspen panels, which give it a finished look and help reduce accidental contact with hot metal. Both packages come with Wi-Fi UKU control and are available above.
We favor a floor-standing heater in the Square. We tried a wall-mounted heater in our own: the curved wall forced it higher than we wanted. The 3D model shows either package in the front corner beside the door. The sauna and chosen heater manuals guide the final installation.
The first Square in North America became our test bench.
Thermory’s assembly animation 16 minutesExperience from the first one
Ben Frizzell owns the first Thermory Square sent to North America. He built his No. 40 near Bend, Oregon. We have used that sauna to learn about heater placement, ventilation and bench layouts: the details that change the experience once you sit down.
Ask us where your feet will rest, how the heater occupies the room, or what to prepare before delivery.
This is our older Large No. 40, with some preassembled panels. Current kits use individual staves. The Medium and Small have their own dimensions and assembly instructions; follow the manual for the kit you order.
Talk through your Square with a BenOur No. 40 going together
Frames from our film of the No. 40. The No. 41 has a solid rear wall; follow its manual.
A Square at home.
From a verified owner
“L shaped seating is a perfect distance from the Huum heater. Enjoying it almost daily.”
The reason to get the details right is simple: a sauna you want to use again tomorrow. See the actual installations in the gallery, then explore the room from your seat in our Studio photo tour.
A few things to get right before build day.
Start level.
The base sets the door, glass and benches up to fit. Check the support positions and diagonal measurements before building upward.
Plan the unload.
Your Square arrives in a large freight crate. We’ll confirm the delivery plan with you. Arrange suitable equipment or an agreed hand-unloading plan with the carrier; liftgate unloading is not included by default. Heater equipment may arrive separately.
Give the wood some care.
Thermal modification improves stability and decay resistance. It does not freeze the color in place. Exterior wood weathers toward silver; use the care guide if you want to maintain the brown tone. Keep the roof cover in good condition and let the sauna dry after use.
Your questions, answered.
What’s the difference between #40 and #41?
The rear wall. #40 has a panoramic rear window; #41 has solid wood at the back. Both have the same glass front, porch, sauna dimensions and L-shaped benches. Choose #40 for a view behind the sauna, or #41 for privacy against a fence or neighboring yard.
How many people fit, and can I lie down?
Thermory lists seating for up to six. The rear upper bench is 6 ft 6 in long, with a 4 ft 3.2 in side bench turning the corner. There is one full-length reclining bench; the side adds seating rather than a second full-length reclining spot. Look at the bench dimensions and the 3D interior with the people you’ll use it with; seated capacity and room to stretch out are different things.
Which heater do you recommend?
Choose the HUUM HIVE Mini package for its open stone basket, or the HUUM CORE package for a compact heater with Thermo-Aspen cladding. Both include Wi-Fi UKU control and the equipment listed in the selector. We recommend floor-standing placement in the Square after trying a wall-mounted heater in our own. Choose a package to see it inside the 3D model.
What does the starting price cover?
The sauna kit, before the heater package and shipping. Build the package that suits you above: each heater package includes controls, stones and the accessories named in the option, and the total updates as you choose. Foundation work, assembly, electrical installation and freight are separate project costs.
Can I add lighting, and what does it light up?
Yes. Lighting is optional, and the ProSaunas kits are in the buying section. Under the benches, the light washes across the wood and floor without shining directly into your eyes. Plan cable routes and a suitable place for the power supply during assembly. Your electrician should follow the selected lighting kit’s instructions.
What dimensions should I use to build the foundation?
The sauna footprint, including the porch, is 82.7 inches wide by 98.8 inches long. Build a firm, level base with support under all four base beams. The installation manual shows their positions. Leave working space for assembly, the door swing and maintenance. A patio or deck needs to support the installed sauna and people using it.
Can I assemble it myself? What does the electrician do?
A capable DIYer can assemble the kit with a helper. Watch our complete build video, then follow the current installation manual: today’s kits use individual staves, while the video shows an earlier version. Your electrician installs the heater supply, controls and sensor to the selected heater’s instructions and local requirements. Check sensor placement before the first heat.
Where does it ship from, and how is it unloaded?
Your sauna ships by freight from a U.S. warehouse. We’ll confirm the plan with you, including driveway access and unloading. For the large crate, arrange a forklift or an agreed hand-unloading plan before dispatch; liftgate unloading is not included by default. Heater equipment may arrive separately.
Can delivery be scheduled for a particular day?
We can plan dispatch around your target timing. The carrier schedules the final delivery appointment, so an exact arrival day cannot be guaranteed. Wait for that appointment before booking a crew around delivery. Agree the unloading method with the carrier in advance.
Can you hold delivery until my site is ready?
Tell us your target date before the order is released to ship. We’ll work through the shipment plan with you. A warehouse hold must be arranged for that order; it is different from leaving a shipment at a carrier’s terminal, where storage charges can apply.
How does the Square compare with other outdoor sauna kits?
Start with the seating layout. The Square’s upper benches turn a corner, so people can face each other. Its rounded shell has a flat floor, two seating levels and a front porch. Compare the actual bench lengths, footprint, wood and heater package against the other sauna you’re considering. You can inspect the Square’s interior and rear-wall options in 3D here.
Why buy the Thermory Square from Sauna Marketplace?
One of our founders still owns the first Square sent to North America. We built it and have used it to test heaters, ventilation and bench layouts. You get that experience when choosing your package and planning the build. We help with assembly questions and work with Thermory when a part or product issue needs attention.
What care will the wood need?
Let the sauna dry after use, clean it according to the care guide, and keep the roof cover in good condition. Thermal modification improves stability and decay resistance. Exterior wood still weathers toward silver. Follow Thermory’s maintenance guide if you want to preserve the original brown color.
The instructions, right here.
Compare Thermory Squares
Which Square is yours?
Start with how you want to sit, then choose your rear wall. No. 40 and 41 share the Large layout; No. 42 and 43 share the Medium layout. No. 45 is the compact sitting sauna.
Compare all five models below. Every Square has a glass front and includes the rain jacket.
Matches your choices
No. 40 Large Square
Sauna kit $9,477.00
Panoramic rear glass
More side-bench room for time together.
- Outside · W × D × H
- 82.7 × 98.8 × 87.9 in
- Upper seating
- 78 in rear · 51.2 in side
- Cool-down space
- Two porch seats
- Rear wall
- See the view through both ends.
Matches your choices
No. 41 Large Square
Sauna kit $8,811.00
Solid wood rear wall
More side-bench room for time together.
- Outside · W × D × H
- 82.7 × 98.8 × 87.9 in
- Upper seating
- 78 in rear · 51.2 in side
- Cool-down space
- Two porch seats
- Rear wall
- Glass front, solid wood behind you.
Matches your choices
No. 42 Medium Square
Sauna kit $8,619.00
Panoramic rear glass
The same reclining length with 15.6 in less overall depth.
- Outside · W × D × H
- 82.7 × 83.2 × 87.9 in
- Upper seating
- 78 in rear · 35.4 in side
- Cool-down space
- Two porch seats
- Rear wall
- See the view through both ends.
Matches your choices
No. 43 Medium Square
Sauna kit $8,008.00
Solid wood rear wall
The same reclining length with 15.6 in less overall depth.
- Outside · W × D × H
- 82.7 × 83.2 × 87.9 in
- Upper seating
- 78 in rear · 35.4 in side
- Cool-down space
- Two porch seats
- Rear wall
- Glass front, solid wood behind you.
Matches your choices
No. 45 Small Square
Sauna kit $5,478.00
Solid wood rear wall
A compact sitting sauna for one or two.
- Outside · W × D × H
- 52.76 × 57.09 × 87 in
- Upper seating
- Compact sitting layout
- Cool-down space
- No porch
- Rear wall
- Glass front, solid wood behind you.
Dimensions include the porch where fitted; allow additional room for door swing, assembly, service and required clearances. The 78 in rear bench in the Medium and Large gives one person room to recline; the side bench is additional seating. Prices are for the sauna kit, before the heater package and shipping; you build the package that suits you. Review the package, delivery and tax on its product page.
Prebuilt
Brushes, Whisks and Body Care
Vents
Anonymous –
Love this sauna. Huge improvement over gym and barrels I’ve used in the past. Thank you fellas!
Verified owner Matt N. (verified owner) –
Love our new sauna. DIY assembly was not to difficult. Kit came with multiple wood slats instead of prefabricated wall sections. L shaped seating is a perfect distance from the Huum heater. Enjoying it almost daily.