Thermory®

Thermac Ash Light Roast is a thermally modified White Ash produced by Bingaman & Son Lumber, one of the leading domestic manufacturers of thermally modified hardwoods in North America. Sourced from responsibly managed Appalachian and Pennsylvania forests, the ash is transformed through a chemical-free process that uses only heat and steam — no chemicals, plastics, or additives — sustained for 14–16 hours in an oxygen-deprived kiln. The "Light Roast" designation refers to a lower peak modification temperature, producing a warm caramel-to-amber tone rather than the deeper chocolate brown of a standard or dark roast. The result is a domestic hardwood with the color character of exotic species like teak or light walnut, while retaining more of ash's natural grain contrast and figure.

The performance story is where thermally modified ash really shines. The modification process breaks down the sugars and hemicellulose that fungi and insects feed on, and permanently reduces the wood's ability to absorb moisture — by as much as 45% compared to untreated ash. Independent testing per EN 350 standards rates thermally modified ash at Durability Class 1 ("very durable"), placing it in the same durability tier as tropical hardwoods like teak and ipe, with an expected exterior service life of 25+ years. Dimensional stability improves dramatically as well: radial and tangential shrinkage drop to under 1%, virtually eliminating the cupping, warping, and seam-opening that plague untreated ash outdoors.

Each board is finished with Cutek Extreme Clear, a penetrating oil engineered to stabilize exterior wood from the inside out. Rather than forming a surface film like paint or varnish, Cutek carries its oils deep into the wood fibers, where they work continuously to slow moisture movement — the primary cause of cupping, checking, and end-splitting. Because the finish penetrates rather than coats, it cannot peel or flake, and maintenance requires no sanding or stripping — just clean the surface and reapply when it looks dry. The clear formulation adds no pigment, allowing the Light Roast's warm caramel tone to show through initially before gradually silvering to a soft gray patina if left unmaintained with a colortone.

Ideal for high-end exterior siding, cladding, soffits, porch ceilings, feature walls, and covered outdoor living spaces where the warmth of a lightly roasted domestic hardwood is preferred over the deeper tones of standard thermally modified ash.

Specifications