Thermo-Spruce 5/4×4 SHP Boards — Benches & Raised Floors
Finished board size ≈ 3.5″ × 1″. Each board shows 3.5″ of face. Boards come in bundles of 4 in these stock lengths (LF): 5.9, 6.8, 7.8, 8.8, 9.8. Price is per linear foot — free samples available.
Bench Planner
The calculator adjusts the actual gap to fill the depth with full boards (no ripping), while staying between 0.10″ and 0.75″. Most benches feel best with gaps around 3/8″–5/8″.
Extra covers waste, trimming, and imperfect pieces.
Includes seat boards + one fascia board along the front. Gaps are auto‑optimized for full boards and efficient use of material.
Raised Floor Planner
The calculator adjusts the actual gap to fill the floor width with full boards (no ripping), while staying between 0.10″ and 0.75″.
Extra covers waste, trimming, and imperfect pieces.
Boards run along the length. Gaps are auto‑optimized so you can use full boards across the width without ripping.
Surfaces (Benches & Raised Floors)
| Surface | Dimensions | Board length | Bundles (raw) | |
|---|---|---|---|---|
| Add benches or floors to list them here. | ||||
Bundles to Order — By Stock Length (rounded per length)
| Stock length (LF — bundle of 4) | Bundles to order | Raw bundles |
|---|---|---|
| Add benches or floors to see the breakdown. | ||
Grand total: 0 bundles · 0.0 raw bundles before rounding.
Order Line Items (Title / Description / Quantity)
| Title | Description | Quantity (bundles) |
|---|---|---|
| Add benches or floors to see line items. | ||
- Application: Interior, Sauna Materials
- Use: Interior Only
- Type: Standard Stock, Bench Board
- Species: Thermo-Spruce
- Color: Golden Brown
- Finish: Unoiled, Unwaxed
- Texture: Smooth
- Installation type: Hidden
- Profile: No Groove
- Installation methods: Screw
- Modification Strength: Medium Intensity
5/4x4 Thermo-Spruce SHP
- Thickness: 1.1
- Width: 3.5
- Coverage: 3.5
| Material main: | Thermally Modified Wood |
|---|---|
| Material secondary: | Wood |
| Designed in: | United States |
| Manufactured in: | Estonia |
One Stop Sauna Shop
Building Benches Using Standard 2x4s
This sauna wood is fairly thin and requires dimensional 2x4's to build the frame underneath. That makes it cheaper, more sturdy, and you can construct it in a way that you won't see the wood.
We also like this method becuase there's no tablesaw involved.
If you are concerned about light wood showing through, you can use Western Red Cedar 2x4's or paint the 2x4s black using Supi sauna wax or SaunaLife Sauna Wax.
Include cross bracing every 16" on center. For extra long spans, consider using 2x6 material for the frame or bracing it from underneath with metal running the full length.
The recommended gap is at least 1/4" to allow airflow and drainage. It's important to note that wider gaps, up to 3/4" is best for airflow and heat distribution. This is where you'll have to weigh aestetics vs performance.
Thermory's Process
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