Allura Soffit is composed of cement, silica sand, cellulose fibers, water and selected additives that have been autoclaved (cured with pressurized steam). Our smooth board technology creates a surface that authentically captures the finely crafted, smooth finish of sanded wood. The most effective system is a balance of air intake and exhaust that creates a uniform flow of air through the attic. This system creates a condition in which the roof temperature is equalized from top to bottom, supplying a consistent airflow along the entire underside of the roof deck.