Why Do Rooftop Photovoltaics Need Waterproofing Membranes?(1)
The roof waterproofing project can be divided into three categories as a whole, structural waterproofing + waterproofing layer corresponds to the highest waterproofing level. Generally speaking, roof waterproofing works can be divided into waterproof cushion layer, structural waterproof layer, and waterproof layer according to the structure from bottom to top. Among them, the structural waterproof layer generally means that the roof base structure itself has waterproof performance. For example, a metal roof with a water guide channel, a waterproof cushion, and a waterproof layer is generally optional.
The waterproof cushion refers to the auxiliary waterproof material in the middle of the metal plate composite board or under the tile, which is used for the waterproofing of the sloping roof and can be regarded as the auxiliary structural layer in the structural waterproofing. The waterproof layer refers to the waterproof membrane or waterproof coating laid or sprayed on the roof structure, which can be used not only for sloping roofs but also for flat roofs. It can be used for both composite sheet metal roofing and single sheet metal sheet roofing. Although only one waterproof cushion layer and waterproof layer need to be selected, due to material limitations, the waterproof performance of the waterproof layer + structural waterproofing is higher than that of the waterproof cushion layer + structural waterproofing.
The materials selected for the waterproof cushion layer and the waterproof layer are different, and the polymer waterproof membrane is used in both, and the effect is better.
When the waterproof membrane is located inside the composite board as a waterproof cushion, since it also needs to undertake functions such as ventilation and moisture resistance, the polymer membrane is more effective when used in it. In the waterproof layer, the main materials currently used are waterproof membranes and waterproof coatings. And because the coil is exposed in the outermost layer, without a protective layer, the polymer coil is more used because of its excellent anti-aging properties.
Waterproof design is an essential part of photovoltaic roofing projects. Adhering to the roof waterproofing policy of "mainly based on row, combined with anti-row". The waterproof design of photovoltaic roof should be based on the nature of use, importance, regional environment and functional requirements of the building, and the material and structure should be reasonably selected.
The technical paths of waterproof design are different. There are currently three mainstream solutions in the market. Since the design of the waterproof scheme is very different under different conditions, the provider proposes different waterproof design schemes according to their own advantages and products. At present, the mainstream design solutions on the market include the following three:
① Structural waterproofing: Refers to the horizontal and vertical guide channels, the water is guided to the annular collector and then drained through the roof drain.
② New color steel tile: The traditional color steel tile is a light steel plate made of Q215 or Q195 low carbon steel with double-sided galvanizing, and its waterproof design life is only 8-10 years, while the new color steel tile is made of Q235 zinc-aluminum-magnesium. Made of alloy, the anti-corrosion, and anti-seepage performance is greatly improved, and the service life can reach more than 25 years.
③ Traditional color steel tile + waterproofing membrane: The photovoltaic roof waterproofing system is constructed by laying a waterproofing membrane on the original roof and providing waterproof bearing prefabricated parts.
Roof distributed photovoltaics can be roughly divided into concrete roofs and metal roofs according to different roofing materials and can be divided into industrial plants, residential buildings, and public buildings according to the type of downstream buildings attached. Among them, the industrial plants are mainly metal roofs, and also include a small number of concrete roofs. Residential buildings and public buildings are dominated by concrete roofs. BAPV and BIPV are different in product and construction, and the reasons for the need for waterproofing membranes are also different.
