Boulevard Structural Outdoor Wood Tiles (SWT) are ecologically responsible, and perform to the highest standard. Designed to combine the best of Tournesol Siteworks’ Boulevard Thermally-Modified hardwood and our VersiJack deck and paver supports, the structural wood tiles have UC3B durability (25+ year life in outdoor settings), and a Class A flame spread rating (ASTM E84). The stunning beauty and deep color of the wood will naturally weather to a beautiful, rich patina. Tournesol's Boulevard outdoor wood starts with domestic ash hardwoods. The lumber is treated at high temperatures and with steam in a special kiln. The natural process changes the chemical make-up of the wood, eliminating sap and resin, which creates a gorgeous dark-colored lumber with exceptional rot, pest and decay resistance. The wood is finished and the tiles assembled - all in the USA! Boulevard SWT are 50% lighter (good for shipping!) and far easier to modify and work with on site than Ipe. All Boulevard wood is free of the arsenic, copper, chrome and other hazardous metals present in pressure-treated wood.