WHY TERMALLY MODIFIED WOOD?

Thermally modified (TM), domestically-sourced wood products offer a superior solution to pressure-treated lumber or composite materials, which are either toxic to the environment and its people, or lack the beauty of real wood and end up as plastic waste in a landfill. TM wood is fully recyclable and is not only recommended for exterior applications, but works beautifully in interior cabinets, countertops, flooring, trims and much more.

HISTORY
Beyond kiln-drying the idea of thermally modifying wood is nearly as old as toolmaking. Early hunters heated wooden spears over the fire to harden them. But it wasn’t until the 1990’s that Scandinavian wood processors and kiln manufacturers, took the process into the lab for closer scrutiny. The resulting technology has been employed for years in Europe, but is only recently making its way into North American retail markets.

THE PROCESS

The proprietary TM process starts where kiln-drying leaves off. Using a combination of heat and steam to collapse, fuse and transform the cellular structure of the wood on a molecular level. Over the course of several days, moisture is removed from the wood as the temperature is increased to 410°F removing sugars and resins in the wood. The boards are reconditioned by slowly lowering the temperature and reintroducing moisture back into the wood. The TM process results in a net 4% to 6% ambient moisture content and approximately a 20% weight reduction. TM creates a dimensionally stable all-natural wood that is resistant to decay, rot, insects, and mold with a Class 1 durability rating and first-class stability that will not warp, cup, or twist when exposed to the elements.

ENVIRONMENTALLY SAFE
Because TM wood contains no harmful chemicals it can be disposed of in the same manner as any untreated wood, such as, disposal in landfills, used as mulch, in campfires, or waste burning. Unlike, pressure-treated or composite materials which are either toxic to the environment and its people, or lack the beauty of real wood and ends up as plastic waste in a landfill.

APPEARANCE & WEAR
Thermal Modification gives the wood Class 1 durability (25+ years), turning the wood to mid to deep dark walnut color throughout. We call it hillbilly walnut in our neck of the woods. TM is a low-maintenance product, but it is NOT A MAINTENANCE FREE product. All wood, including TM wood is vulnerable to UV light, fading to a silver-gray faster than unmodified wood, so refinishing may be necessary every year or two to maintain the original wood color. Other than changing colors and some minor surface checking, the sun has little or no effect on the material.

SUPERIOR WORKABILITY
TM is a natural wood and as such can be handled and utilized in the same manner as any natural wood material. In fact, because of the low moisture content the material cuts and machines better than most wood. However, the TM process that leaves the wood harder also reduces its splitting resistance.

PHYSICAL & STRENGTH PROPERTIES

TM is drier at 4% EMC and has a 10-25% lower weight and density compared to its kiln dried counterpart. The strength of wood has a strong correlation with density. Due to decreased strength, TM wood is not used in structural joists, stringers, beams, support posts, columns or other load-bearing applications.

CUTTING, DRILLING & FASTENING

Pay special attention to saw and tool coarseness/fineness to improve end results. Saw speed will have an effect on the cut quality; generally, the higher the saw power, the better quality the cut.

• Saws: Use fine tooth carbide tipped (30-tooth minimum)
• Drill Bits: Use sharp standard round woodworking bits
• Pre-Drill holes for nailing using sharp bits with attention to minimize tool pressure
• Use exterior grade stainless steel fasteners. Galvanized fasteners can create permanent black discolorations. 
• Fasteners should be applied a minimum of 5/8” from board edge and a minimum of 1” from the board ends.

DECKING & STAIR APPLICATIONS

Use self-tapping composite decking screws, spiral shank nails or pre-drill holes if using exterior grade nails or screws.

• 16” span center-to-center on most residential applications
• 12” span center-to-center on commercial applications
• 1/4″ gap between adjacent deck boards is recommended

FINISHING

TM wood can be left unfinished or readily stained or painted with a low viscosity oil-based finish. Because the material will not absorb additional moisture, any water-based stains or paints will not penetrate the wood. Our builders have had great success with Cutek product line of finishes. For optimal results, apply the finish to all surfaces including the cut ends.

DIRECT GROUND CONTACT

TM wood should be installed a minimum of 2” above grade. Where structural performance is not critical and periodic drying of the surface is allowed, ground contact with good drainage which includes sand is allowed. Due to bacteria in the air or dirt carried by the rain, TM positioned near the ground can grow fungi on the surface, the same as stone and most other surfaces. This is only on the surface and can be removed by wiping or scraping.

TERMITES: TM wood has improved termite resistance as the sugars in the wood are removed in the TM process. Nevertheless, for the areas with increased termite activity, additional protection is recommended.