PROSAUNAS Thermo-Spruce 1x4 (15mm x 90mm) T&G STS4

$5.54
Ships in about 2 - 4 Weeks
Not a next-day item. We’ll keep you posted at every step.
Shipping included
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PROSAUNAS Thermo-Spruce tongue and groove 1x4 STS4 profile creates a bold look and is recommended for sauna walls and ceilings. Thermo-Spruce wood has a smooth refined finish and a traditional rustic charm with its characteristic rich amber color and highly figured knotty look.

The narrow, angular grooves of STS4 wall panels produce the modern nickel-gap effect. STS4 can create a sophisticated contrast effect when combined with other wood profiles. PROSAUNAS distinctive nickel-gap panels are precision-milled to our precise specifications, creating a contemporary Scandinavian aesthetic.

Thermally modified spruce is highly desirable for use in saunas. Thermal modification is a completely organic process that uses heat, steam, and pressure to physically enhance the properties of the wood. Sauna wood that is thermally modified is more dimensionally stable, more water-resistant, has an ideal moisture content, and is far superior to untreated wood for resisting decay, pests, and harmful fungi.

PROSAUNAS carefully selects only the finest wood from Northern Europe and Canada, assuring that the quality and consistency of our wood selection is the best available. Our team has more than 55 years of experience crafting premium sauna rooms across North America, and we only offer wood that meets our exacting standards. Because of our total commitment to quality, we can ensure your wood order will arrive to your satisfaction.

Wood Sizing - Nominal vs. Actual Lumber Sizes: In North America, wood sizes are given in "nominal" measurements, which is the lumber’s size when it is cut from moist logs. After shrinkage from drying and surfacing, the actual size of lumber will be less than its nominal size. Please see the diagram for actual dimensions.

  • Ideal for sauna walls and ceilings
  • Greater durability
  • Resists warping
  • No chemical treatment
  • Eco-friendly
  • Ideal moisture content
  • Narrow, angular grooves
  • Natural wood
  • Can be combined with other profiles
Species Spruce
Finish Thermally Modified
Wall Coverage 3.1" (80mm)
Product Width 3.54" (90mm)
Product Thickness 0.59" (15mm)
Shipping Length Up to 10'
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(512) 299-9993 | info@olisaunas.com

You'll get a confirmation email right away. When your order ships you'll get tracking, and one to two days before delivery our team calls to schedule an appointment.
Lead times vary by model and are listed on each product page. Once it ships, transit is usually 3-7 business days.
Most traditional saunas take about 1-2 full days for two people to assemble. They are designed for DIY assembly and include clear instructions, but they are still a real project and not something you should expect to knock out in an hour or two. Plan on using basic tools like a power drill/driver, level, rubber mallet, and standard hand tools. Infrared saunas are typically much quicker to assemble, usually taking about 3-4 hours with two people. If you want us to assemble it for you, we have assembly services available in select areas.
Anything flat, stable, and free of pooling water. A wooden deck, concrete pad, pavers, or gravel all work. We don't recommend setting it directly on turf.
Most 6–9kW heaters run on 240V and need their own dedicated circuit wired by a licensed electrician. The LED lighting runs on standard 120V. We'll walk you through exactly what your chosen heater needs.