Fanfold Underlayment - GreenGuard Q Series

When every penny counts, you can rely on the performance of our most economical fanfold siding underlayment. The Q-Series products have an extruded polystyrene foam (XPS) core with high-impact polystyrene capsheets on both sides, which make it one of the most durable products currently available. These products are also perforated to allow potentially harmful moisture vapor to escape so that it does not become trapped in the wall.