Waterproof issues are crucial for the construction of distributed photovoltaic systems on rooftops, mainly for the following three reasons:

① The current waterproof lifespan is short and does not match the lifecycle of photovoltaic power plants. The operating life of photovoltaic power plants is usually 25 years, while the current waterproof warranty period in China is only 5 years. In actual use, leakage phenomena are common after several years. For existing roofs, water leakage and hidden dangers have become important issues.

② House water leakage will greatly affect the operation of photovoltaic power plants. Water leakage will cause the photovoltaic power station to suspend operation or even completely dismantle for waterproofing repairs, resulting in significant economic losses. Not using waterproof solutions may accelerate short-term returns, but due to the long operating life of the power station, if repairs are interrupted due to water leakage, it will have a significant impact on the long-term investment return level.

③ The construction of rooftop photovoltaics will affect the original waterproof layer. The current installation process of photovoltaic brackets is mostly through type, which will cause damage to the original waterproof layer, and improper treatment of the drilled holes will result in leakage. If it is a metal roof, the construction process may cause the joints of the metal roof to loosen, resulting in leakage. For factories and buildings where rooftop photovoltaics are mainly used, severe water leakage can cause business closures and economic losses. Therefore, factory owners usually pay more attention to waterproofing.