These water-resistant barriers play an important role in maintaining moisture by resisting outside penetration from liquid water, yet at the same time allowing water vapor to escape. Many layers of house wrap function to keep a building weathertight, structurally sound and energy efficient. At Lyndhurst Lumber, we use both Tyvek by Dupont, the most popular brand, as well as GreenGuard for extreme durability and six months of UV-stability. It comes in rolls of 100 lineal feet by 9 feet, and 100 feet by 10 feet.