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Shop sauna heatersThermory Black Thermo-Spruce 1×4 STS4 Coverage
Sauna wood coverage planner for brushed & waxed black Thermory STS4 1×4 cladding.
Each board shows 3.5″ of face. One bundle = 6 boards ≈ 1.75 ft across. Stocked lengths (LF): 4.9, 5.9, 6.8, 7.8, 8.8, 9.8. No subtraction for doors/small windows. Over 9.8′: we cut in half & double (center seam).
Rectangular Sauna
Length × Width × Height. Use +/- or type inches for perfect sizing.
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in
Tip: Shift = 6″
3′7′16′
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in
Tip: Shift = 6″
3′7′16′
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in
Tip: Shift = 6″
6′8′10′
Thermory wood is perfect, but shipping and installation isn't. We recommend adding 10%.
Per Room Result — —
Runs ≤ 9.8′: single pieces. Longer runs: center seam (bundles doubled).
Sauna Wood Calculator
Plan each wall separately, then the ceiling. Use +/- or type inches.
Wall — This Wall
Thermory wood is perfect, but shipping and installation isn't. We recommend adding 10%.
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in
Shift = 6″
2′7′16′
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in
Shift = 6″
6′8′10′
Per Wall — —
Over 9.8′ horizontally → we “cut in half & double” (center seam). Try vertical to avoid seams.
Ceiling — This Ceiling
Thermory wood is perfect, but shipping and installation isn't. We recommend adding 10%.
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in
Shift = 6″
3′7′16′
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in
Shift = 6″
3′7′16′
Per Ceiling — —
Surfaces
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Bundles to Order — By Stock Length (rounded per length)
| Stock length (LF — bundle of 6) | Bundles to order | Raw bundles |
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Grand total: 0 bundles · 0.0 raw bundles before rounding.
Order Line Items (Title / Description / Quantity)
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Why Black Thermo-Spruce Changes Everything
For years, sauna builders have been limited to light woods or expensive exotic options when clients wanted something darker and more dramatic. Not anymore. Thermory’s Black Thermo-Spruce delivers that coveted modern aesthetic without the premium price tag.
The intense thermal modification process using only heat and steam creates the perfect canvas for black sauna wax color while making the wood incredibly stable – no shrinking, warping, cupping, or rot when properly installed.
The wire-brushed texture elevates this wood from beautiful to extraordinary. The brushing process enhances the natural grain patterns, creating subtle valleys and peaks that play with light and shadow. Combined with the protective wax finish, you get a surface that’s visually striking, low maintenance, and built to withstand the demanding sauna environment.
Installation That Makes Builders Smile
Every contractor we work with raves about Thermory’s consistency and quality, and this Black Thermo-Spruce is no exception. The STS4 tongue and groove profile installs smoothly with hidden fasteners, creating clean lines without visible hardware. Each bundle contains perfectly milled boards that fit together seamlessly.
Actual wall coverage: 3.5 inches per board
Profile: STS4 Tongue & Groove
Thickness: 0.59 inches
Texture: Wire-brushed for enhanced grain
Finish: Waxed for durability and protection
Build Your Complete Black Sauna
At Sauna Marketplace, we make it easy to create a cohesive design. Black sauna wood is a legendary pairing with Thermo-Aspen benches and accent walls for stunning contrast. We have everything you need to complete your vision.
The Details That Matter
- Intense Thermal Modification: The deepest level of thermal treatment creates the rich color and ultimate stability
- Wire-Brushed Texture: Enhances natural grain patterns for visual and tactile appeal
- Waxed Finish: Pre-applied protection that’s ready to install
- Hidden Fastening System: Clean installation with no visible hardware
- Thermory Quality: From the global leader in thermal modification with decades of expertise
Your One-Stop Sauna Shop
Create stunning contrast or go full monochrome – the choice is yours. Here are some perfect pairings for your black sauna:
- Natural Thermo-Aspen Benches – Create dramatic contrast
- Thermo-Aspen Accessories – Backrests, headrests, and floor grids
- Modern Black Sauna Door – Complete the contemporary look
- Adjustable Air Hatches – Available in matching wood species
The Thermory Difference
When you choose Thermory Black Thermo-Spruce, you’re not just getting beautiful wood – you’re getting the expertise of the global leader in thermal modification. Every board is crafted in Estonia using sustainable forestry practices and cutting-edge technology that transforms ordinary spruce into extraordinary sauna material.
The intense thermal modification process doesn’t use any chemicals – just heat and steam. The result is wood that’s naturally resistant to moisture, decay, and temperature fluctuations. Add the wire-brushed texture and protective wax finish, and you have a product that’s as durable as it is beautiful.
Ready to Go Bold?
Black Thermo-Spruce is available now and ready to ship. Whether you’re building a sleek modern wellness center or creating a dramatic home sauna, this is the wood that makes a statement. Order your free sample today and experience the color, texture, and quality that’s setting a new standard in sauna design.
Need a Quick Quote?
Just bring your dimensions, and we’ll calculate everything you need for your black sauna project.
Specifications:
- Made in: Estonia
- Species: Spruce (Picea abies)
- Thermal Modification: Intense
- Color: Black
- Texture: Wire-brushed
- Finish: Waxed
- Profile: STS4 Tongue & Groove
- Coverage: 3.5 inches
- Thickness: 0.59 inches
- Installation: Hidden fastening system
Across the Gulf of Finland, Estonia has emerged as a powerhouse in the global sauna industry. Thermory leads the way with innovative thermal modification technology, modern manufacturing, and a commitment to creating premium sauna products that push the boundaries of what’s possible.
Installation
When building a sauna, make sure the installation work is performed with quality and precision to make the wood last longer. Wood as a natural material requires regular maintenance to preserve its properties.
Always check the wall panels immediately on receipt to identify any transport damage. Never install a defective product. When installed, the product is deemed to be of acceptable quality.
Storage
Best practice is to store your wall paneling in the same room where they will be installed for a few weeks before installation to allow the wood to acclimatize to the temperature and humidity conditions in the room.
Store the wall paneling on a flat surface, openly stacked and above the floor surface, for example on joists. Make sure that joists would be at least 11.8 inches to avoid bending. This will enable air movement between the panels.
Wall paneling must be stored at the same temperature at which they are going to be installed. The ideal storage temperature is 59–72 °F.
If there is a radiant heater or other heat source in the room used for storing the wall paneling, make sure the humidity level does not get too high and the temperature does not exceed 77 °F.
Wall paneling must be stored in unopened packages. Remove the heat-shrinking film immediately before installation.
Prep for Installation
Sauna wall paneling are installed as part of living area finishing works. When planning the order of construction work, keep in mind the wall paneling does not tolerate changes in humidity during construction.
Make sure sufficient ventilation is provided in the sauna room.
Make sure you have enough material, as there may be slight differences in shade between production batches.
The approximate material loss varies between 5-10% depending on the length for wall paneling.
Any wet operations must be performed before installing the wall paneling. Performing wet operations after the wall paneling have been installed will cause the paneling to absorb moisture and swell.
Installing Thermory Sauna Wall Cladding
Open several packages so you can better match your wall paneling.
Thermory and Sauna Marketplace recommend using a staple gun and stainless steel clips for installing the wall paneling.
First install the underlay battens to afix the wall paneling to. The battens must be at least 0.79” thick and 1.8” wide. If the wall paneling is going to be placed horizontally, install the battens vertically. Vertical wall paneling, however, requires horizontal battens. The battens must ensure air movement behind the wall paneling across the entire extent of the paneling.
Make sure the battens are straight and level before installing the wall paneling. The recommended batten spacing is 15.7”. The batten spacing must not exceed 23.6”.
When installing wall paneling horizontally on adjacent walls of a room, start installing the paneling row by row on all walls at once, circling the room one row at a time. This way you can align the ends of the paneling with precision in the corners.
Prebuilt
Sauna Brushes
Vents