Thermo-Spruce 1x4 Nickel-Gap Tongue & Groove Paneling

Description

Thermo-Spruce is spruce that has been heat-treated to drive out moisture and resins, leaving a dimensionally stable paneling that resists the swelling, shrinking, and warping that untreated wood experiences in sauna conditions. The 1x4 profile (15mm × 90mm) in a nickel-gap tongue-and-groove pattern creates clean, evenly spaced shadow lines across your wall or ceiling — a look that reads as intentional rather than incidental.

The nickel-gap detail is functional as well as visual: the small reveal between boards allows for minor movement in the wood without the joints opening or closing noticeably, and it simplifies installation because you are not trying to close every board tightly against the last. Tongue-and-groove milling keeps each plank aligned flush through the wall surface, eliminating the need for face fasteners and producing a smooth plane that is easy to clean.

Key Features

• Heat-treated spruce (thermo-spruce) has resins and excess moisture removed, reducing the biological activity that leads to warping or mold in high-humidity sauna environments.
• 15mm × 90mm (1x4) cross-section gives enough thickness for structural rigidity on standard stud spacing without adding unnecessary thermal mass to the wall.
• Nickel-gap profile builds a small, consistent reveal between boards, accommodating natural wood movement while maintaining a uniform finished appearance.
• Tongue-and-groove milling aligns every board flush to its neighbor and allows blind fastening, so no nail or screw heads are visible on the finished surface.
• Available in ten lengths from 1 ft to 10 ft, letting you choose boards that minimize waste and avoid unnecessary seams for your specific wall and ceiling dimensions.

1'

• 292 mm (approximately 1 ft) — useful for fill pieces, short runs, or accent sections where a full-length board would generate significant off-cut waste.

2'

• Approximately 2 ft length suited to low walls, benches, or tightly framed sections.

3'

• Approximately 3 ft length for mid-range runs where longer boards would be awkward to maneuver in a confined space.

4'

• Approximately 4 ft length aligns with common framing intervals and reduces seam frequency on standard sauna walls.

5'

• Approximately 5 ft length works well for walls in compact one- and two-person sauna cabins.

6'

• Approximately 6 ft length covers typical residential ceiling heights in a single board, eliminating mid-wall seams.

7'

• Approximately 7 ft length spans taller wall sections or angled ceiling runs without requiring a join.

8'

• Approximately 8 ft length matches standard stud-wall height and is a common choice for full vertical runs.

9'

• Approximately 9 ft length suits larger or custom-height sauna builds where an 8 ft board falls short.

10'

• Approximately 10 ft length minimizes board count and seams on long horizontal ceiling or wall runs in spacious sauna rooms.

SHIPPING & DELIVERY

LUMBER CURBSIDE FREIGHT — QUOTED

Lumber ships curbside freight. The quote is based on the amount of lumber ordered. Our team will provide a freight quote after checkout.

This is the only shipping option when the order includes lumber, including an order that also has a heater. Checkout does not offer another shipping choice on that order.

CURBSIDE

The driver brings the lumber to ground level. Boards over 8 feet ship on a pallet and may need a dock or hand offload. That is part of the quote. We confirm access before it ships.