Decking

Four species across two lines. From Carbon Smart Wood: Thermal Oak, with Class 1 durability, and Silky Cedar, a naturally durable cedar that weathers to a silver patina. From Arbor Wood Co.: Thermal Ash, the gold standard for thermally modified hardwood, and Thermal Pine, a lightweight softwood built to last outdoors. All of it is made in the USA, and both lines are covered by limited 20-year warranties.

Wood that has been through a three-phase kiln process using only heat and steam, with no chemicals. The process removes the moisture, sugars, and starches that cause rot and insect damage, and deepens the color through the full thickness of the board. Carbon Smart Wood decking is certified to AWPA Use Class UC3B (above ground, exposed), sourced and processed entirely in the U.S., and suitable for any outdoor North American climate.

Pressure treatment forces chemical preservatives into the wood. Thermal modification changes the wood itself, so there is nothing to leach out over time. Thermal Pine, for example, lasts 2 to 3 times longer than pressure-treated lumber, holds its color without constant upkeep, and resists warp and decay for decades.

Composites are largely plastic. Thermally modified decking is solid wood through and through: real grain, real warmth, and a surface that can be sanded and refinished rather than replaced. At the end of its service life, it is still just wood.

No finish is required. Left unfinished, boards weather to a silver-gray patina over 8 to 12 months. That is a color change, not a performance change. To hold the original tone, apply a penetrating oil with a UV colortone (both lines recommend CUTEK Extreme; clear oils alone are not UV resistant) and reapply as needed. A deck cleaner or light sanding removes silvering and restores the original color.

Thermally modified decking is expected to last 25+ years without serious degradation, warping, or buckling, and Thermal Oak is Class 1 durable, the highest rating for decay resistance. Both lines carry limited 20-year warranties covering fungal degradation, buckling, and structural failure in above-ground installations, when installed and maintained per manufacturer instructions.

All of it is American. Silky Cedar is sourced from Pacific Northwest forest thinning and post-fire removal, part of what makes it one of the most sustainable cedars in North America. Thermal Oak is salvaged American red oak given a second life. Arbor Wood's Thermal Ash and Thermal Pine are domestically sourced and responsibly harvested.

Three things. First, thermally modified wood is not structural. Frame the substructure with standard lumber, and never install boards in contact with the ground or a rooftop; the assembly needs airflow underneath. Second, fasten with stainless steel only, whether hidden clips or face fastening. Nails void the warranty. Third, acclimate boards on site before installation, and plan joists at 16 inches on center. Full installation guides are below.