Waterproof and breathable membrane concept:
Waterproof and breathable membrane is a new type of polymer waterproof material. From the production process, the technical requirements of the waterproof and breathable film are much higher than the general waterproof material; at the same time, from the quality point of view, the waterproof and breathable film also has the functional characteristics not possessed by other waterproof materials. The waterproof and breathable membrane enhances the airtightness and watertightness of the building, and its unique steam permeability can quickly discharge the water vapor inside the structure, avoid the structure of mold, protect the property value, and perfectly solve the moisture and human health. A new energy-saving material that is healthy and environmentally friendly.
History of waterproof and breathable membranes:
In the 1940s, German architects discovered that the self-adhesive and airtight characteristics of asphalt waterproofing membranes and coating waterproof materials caused the residual moisture in the concrete structure to be enclosed in the structure, and the water vapor in the concrete structure could not be dissipated. Leading to mold and wall mold, indoor air quality and human health are seriously threatened. Therefore, the German construction industry began to use the roofing layer with breathability to replace the self-adhesive coil and the coating film. The breathable cushion is laid on the roof base layer, so that the water vapor of the cast-in-place concrete roof panel is quickly discharged. Going out, thus avoiding the breeding of mold.
In the historical context of the time, people's understanding of building energy efficiency was not enough. In the 1970s, with the outbreak of the world energy crisis, European and American countries paid more and more attention to building energy conservation. Energy experts have found that this kind of permeable cushion can effectively prevent the moisture and mold problems by discharging the water vapor of the cast-in-place concrete roof. However, a large amount of water vapor is discharged to the insulation layer, and the thermal performance of the insulation material is seriously damaged.
In the mid-20th century, experts from the American and Canadian Building Standards Association found that the condensation of water vapor in the exterior walls and roofs of buildings would seriously affect the performance of building insulation materials and the durability of the envelope structure, leading to mold growth. The main cause of the damp is the liquid phase water and vapor phase water that permeate into the interior of the enclosure by means of the outside air of the building. Since then, some buildings in the United States have used waterproof membranes and laid out on the outside of the insulation layer as a building covering system to enhance the airtightness and watertightness of the building. However, the waterproof membrane is not breathable, and the moisture of the envelope structure cannot be dissipated. The problem of moisture protection cannot be completely solved.
After continuous scientific research and practice, experts from the construction industry in Germany and the United States finally found that the gas-permeable roofing cushion was changed to a gas-tight coil as a vapor barrier layer on the roof of the roof, so that the water vapor of the cast-in-place concrete roof was certain. To the extent that it can be discharged, slowing the discharge of water vapor from the concrete roof to the insulation layer; using a gas permeable waterproof membrane as a building coating system (hereinafter referred to as a waterproof gas permeable membrane), preventing liquid phase water and vapor phase water from infiltrating outside the building. At the same time, the water vapor of the insulation layer is quickly discharged. The use of the vapor barrier layer and the waterproof and breathable membrane strengthens the airtightness and watertightness of the building, solves the moisture and mold, and effectively protects the thermal performance of the enclosure structure, thereby realizing the purpose of energy conservation.
In the late 1980s, the waterproof and breathable membrane solution was widely promoted in developed countries in Europe and America. It was widely used in residential buildings and public buildings. The waterproof and breathable membrane building structure was praised as “the house that will breatheâ€. The waterproof and breathable membrane is laid on the insulation layer to effectively protect the insulation layer. The upper layer of the insulation layer does not need to be poured with fine stone concrete, and the optimization of the scheme reduces the construction cost. Japan, Malaysia and other countries have also introduced German and American technology, and began to mass produce and apply waterproof and breathable membranes.
In recent years, the Chinese government has paid more and more attention to building energy conservation, which has made the waterproof and breathable membrane scheme popularized in China, and has formulated the "waterproof and breathable membrane building structure", "formed steel plate, sandwich panel roof and exterior wall building structure". Special special atlas.
Waterproof and breathable membrane works:
In the state of water vapor, the water particles are very small, and according to the principle of capillary movement, the capillary can be smoothly infiltrated to the other side, thereby causing vapor permeability. When the water vapor condenses into water droplets, the particles become larger. Due to the surface tension of the water droplets (water molecules collide with each other), the water molecules cannot smoothly escape from the water droplets and penetrate into the other side, which is to prevent The penetration of water occurs, making the vapor permeable membrane waterproof.
Waterproof and breathable membrane material:
The technology of waterproof and breathable membrane was first introduced from Europe and the United States. However, the production process of domestic products is varied, and the quality of each manufacturer's products is uneven, failing to form a unified quality standard.
Nowadays, the more popular design in the world is made of polypropylene fabric + polymer vapor permeable membrane + mesh reinforcement rib + polypropylene fabric laminated by hot melt adhesive. The water-repellent gas-permeable membrane material produced by the production process has stronger waterproof and vapor permeability performance than the domestic products, and the material has higher tensile strength, improves the efficiency of engineering construction, and reduces the material during the construction process. loss.
Editor in charge: Zhu Ling
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