Premium Thermally Modified ASH SIDING is a natural wood material with an attractive look and natural durability. Due to the thermo-modification process, wood becomes durable for at least 25 years. In the process, wood changes its molecular structure and becomes similar to 350-year-old lumber. It is a 100% Green product with all the advantages of natural wood and a luxury appearance. Versus pressure-treated softwoods: Thermo Ash Siding is a 100% "Green" product that won't crack, shrink, or swell like pressure-treated lumber. Over its lifespan, it costs 3-4 times less. Versus exotic woods: Thermo Ash Siding is significantly lighter, more dimensionally stable, and easier to work with. Versus composite, plastic, and fiber cement: Thermo Ash Siding doesn't overheat under sunlight, and it is real wood. Versus other thermo-ash sidings on the market, our Ash Siding comes factory-oiled on all four sides, is perfectly trimmed in random lengths ranging from 4 to 8 feet, and offers consistent color. Siding can be used indoors and outdoors. The boards are covered with a protective oil on all four sides.