House-wrap Waterproof breathable membrane is a new type of spunbonded polypropylene composite polymer waterproof breathable material, the product has good water resistance, breathability and anti-aging properties, the product has a unique , Allowing the water vapor to pass freely, but not to penetrate after condensing into water, thereby ensuring dry and comfortable building, while avoiding condensation of water to destroy the building's maintenance structure (roof and wall). Waterproof and vapor permeable membrane is a layer of film covered in the building insulation layer, and waterproof membrane technology is through strengthening the building air tightness, water tightness to achieve energy conservation, protection of living environment, thereby enhancing the building Of the durability and comfort, can be more effective to ensure maintenance of the structure (external walls and roof) of the dry, and play a significant effect. 1. Strengthen the construction of air tightness, water tightness Practice has proved that no matter what facade form, or the form of roofing, can not guarantee the enclosed structure of the closed. To the outside wall, the plaster cracking is difficult to avoid, hanging plate is difficult to tightly, and simple masonry block is more impossible to achieve "airtight wall." These problems, in the construction of yin and yang, lap and doors and windows around the more significant. Through these non-closed pores, air flow and water vapor can invade the envelope, so that the building energy consumption, durability and comfort have a serious impact. 2. Building energy consumption Rainwater and water vapor intrusion into the enclosure will reduce the effective thermal resistance of the insulation, resulting in more energy consumption. Of course, the impact of water vapor on the different insulation materials are different. Intrusive airflow will form a convection cycle within the building envelope and will also reduce the effective thermal resistance of the insulation, resulting in more energy consumption. Similarly, the impact of air flow on the different insulation materials are different. As air flows into the room, people will have to use more bulky HVAC equipment to compensate for the heat / energy losses, increasing building energy consumption. 3. Building durability Intrusion of water vapor inside the enclosure will result in condensation (condensation) of water vapor in the walls of the walls, accelerating the aging of building materials such as corrosion of steel and decay of wood, which can have a serious impact on the durability of the building. In this case, 4. Architectural comfort The intrusion of airflow will adversely affect the thermal comfort of the building; the pollutants deposited on different building components and the radiation from building materials or outdoors, thus affecting the indoor air quality; entering the building envelope Internal water vapor, for the envelope structure of water vapor condensation to create the conditions that lead to mold formation, thus the indoor air quality and the health of residents affected. Visible, strengthen the construction of air tightness, watertightness of the building energy efficiency, environmental protection is essential. 5. Building permeability   Due to the existence of indoor and outdoor temperature difference, the building envelope of the internal condensation is difficult to avoid. In practice, however, a moisture problem can only be caused when the enclosure is in a damp state, resulting in adverse effects on building energy consumption, durability and comfort. Therefore, in order to avoid the occurrence of problems, to ensure the permeability of the building, it can be through the form of water vapor diffusion to the outdoor to achieve natural drying, it is particularly important.