Advantage Thermally Modified Ash 1x6 Standard boards offer the natural beauty of real hardwood with the added benefits of thermal modification for enhanced durability and stability. Resistant to rot, decay, and moisture, these versatile boards are ideal for a wide range of indoor and outdoor applications, including siding, cladding, soffits, ceilings, and custom millwork projects. Thermally Modified Ash provides a modern, high-end wood appearance with long lasting performance.