Noncorrosive, fire-retardant, structurally sound yet lighter than untreated wood, and resistant to mold, mildew, termites and rot-pressure-treated wood is perfect for outdoor projects like swing sets and decks. But until TimberSIL came along this year, the lumber hasn’t been so human-friendly. In 2002 the Environmental Protection Agency started phasing out the longtime standard additive, green chromated copper arsenate, for residential use because it leached arsenic into the ground. Its replacement, alkaline copper quaternary, was less toxic but had a bad habit of eating away at metal fasteners, like nails.
TimberSIL employs sodium silicate, a mixture of sand and soda ash used since the 1800s in detergents and as an egg preservative. Lumber soaks in it under pressure, then bakes until an insoluble matrix of amorphous glass hardens throughout the wood. No amount of rain or wear will remove it-bugs can look, but they can’t touch. $4.50 per 8-foot 2×4