The original thermowood · Milled in Greenville, SC
American-milled thermowood, priced for real projects.
At your door in 2–4 weeks.
International ThermoWood Association member · Thermally modified in Finland · Milled in Greenville, SC · FSC®-sourced softwoods
The original
Invented in Finland. Treated in Finland. Milled in Greenville.
Thermal modification is a Finnish invention, and ThermoWood® is its original form — the process the imitators are measured against. We bring it over unchanged: boards treated in Finland to the ITWA standard, then milled to profile in our own shop in Greenville, SC. The gold standard of thermowood, minutes from your jobsite instead of an ocean away.
Why thermowood
Heat and steam. Nothing else.
At 212 °C, heat and steam permanently change the cell structure of the wood. What comes out of the kiln behaves differently than the wood that went in — and keeps behaving that way for decades.
Durability
Class 1–2 rot resistance
The most durable class a softwood can reach (EN 350), rated 25+ years above ground — and backed by our 25-year warranty against rot and decay.
Stability
Half the movement
Equilibrium moisture drops by roughly half, so boards swell and shrink far less through seasons. Joints stay tight, lines stay straight.
Chemical-free
Nothing to leach, ever
No copper, no borates, no film. Safe to cut, sand, and burn as offcuts. The color runs all the way through the board.
Weathering
Ages to silver, honestly
Left uncoated, the honey-brown face weathers to an even silver-grey patina — expected weathering, not a defect. Oil it if you’d rather keep the roast tone.
Four categories
A board for every surface.
01
Exteriors
Cladding
Tongue-and-groove, open-joint, and rainscreen profiles in pine, radiata, and ayous.
02
Outdoor living
Decking
Stable through freeze-thaw cycles, splinter-free, and cooler underfoot than composite.
03
Interiors
Interior
Aspen and pine paneling for walls, ceilings, and feature surfaces.
04
Heat & steam
Sauna
Aspen and radiata — the two woods Finland has always trusted next to the stove.
Saunas
Cut for the hottest room in the house.
Aspen and radiata wall paneling plus made-to-order bench kits, cut from your room dimensions. Thermowood runs cooler to the touch and never bleeds resin — it’s what Finnish saunas are built from.
The mill
Milled to profile in Greenville, SC.
The lumber is thermally modified in Finland. Everything after that happens in our shop: profiling, end-matching, grading, and packing. When you call about an order, you’re talking to the people standing next to the moulder.
Because we run the machines, we can run your drawing — custom profiles are a flat tooling charge, not a negotiation.
Recent work
Built with our boards.
01
Residential
Summit Drive
Greenville, SC · Blom Design Studio · Pine TG-Lap and TG-Triple cladding.
02
Commercial
Norden on Stone
Greenville, SC · Blom Design Studio · TG-Triple pine cladding and pine decking.
03
Residential
Lake View Court
Lake Keowee, SC · Blom Design Studio · TG-Triple pine cladding.
Straight math
Better than cedar. Fraction of composite.
Thermowood outlasts clear cedar on durability and stability, and holds its own against composite — while staying a real, workable wood.
Relative material cost for comparable exterior boards. Request a quote for current pricing.
Samples
Hold it first.
Eight 8-inch boards across all four species, with color cards showing the fresh-milled tone and the weathered patina, and profile cross-section cards for your drawings. Free for real projects — request it with your zip and what you’re building.
The fastest way to understand thermowood is to hold it. Feel the weight, check the profile against your section, and leave a board on the client’s table.
Send square footage and a profile — or just a drawing — and we’ll price it within one business day. Most orders ship in 2–4 weeks.