Why Do Rooftop Photovoltaics Need Waterproofing Membranes?(2)

Application Scenarios of Waterproofing Membranes Under Different Paths

There is room for improvement in the original roof + installation link, and the waterproofing membrane can enhance the effect at the bottom.

According to the different roof structures, we have sorted out the process of installing BAPV on two roofs, and by splitting the construction links, we can get the necessity of waterproofing membranes in them. On the whole, BAPV installation needs to go through the following steps:

1） Detection of roof conditions: If it is a concrete roof, it is necessary to detect the degree of water leakage. If it is a color steel tile metal roof, it is necessary to determine the thickness of the color steel tile to ensure the load and detect the corrosion condition to determine whether there is water leakage. However, if the current waterproof design age fails to match the service life of the photovoltaic modules, it is necessary to replace or add waterproofing.

2） Installation of supports: If it is a concrete flat roof, the supports are usually installed by adding a cement base or ballast. If it is a concrete tiled roof, the tiles need to be removed, holes are drilled behind the tiles to install prefabricated supports, and then the tiles need to be put back. If it is a metal roof, there are two ways, one is to add purlins or a raised seat, and the other is to fix the support on the metal roof by gluing, clamps or bolts.

3） Install the bracket: After the support is installed, install the guide rail and the horizontal and vertical water guide above the support.

4） Install photovoltaic modules: After installing the brackets, fix the photovoltaic modules on the guide rails through the fixing brackets, and install waterproof covers between the photovoltaic modules. The above installation steps put forward higher requirements on the performance of roof waterproofing products for buildings.

Under the traditional waterproofing standard, the reasonable service life of waterproofing is only 10 years, and the residual quality of the original roof varies. The service life of photovoltaic modules greatly exceeds the current roof waterproofing standards, and it is the general trend to upgrade the roof waterproofing system. The operating cycle of photovoltaic modules is generally 25 years. After 25 years, only the power generation efficiency decreases, and its real operating life may exceed 25 years.

Therefore, the waterproof membrane is the basic structure of the primary waterproof structure of the photovoltaic roof. In the context of waterproofing upgrades, waterproofing membranes, as one of the main technical paths for photovoltaic roof waterproofing, occupy a certain market space.

In terms of subdivision, industrial and commercial BIPV roof systems adopt an integrated sales model, and waterproofing membranes are usually included in the system. In the BIPV products currently used in industrial and commercial roofs, the waterproofing membrane is usually packaged and sold in the system, that is, the use of the waterproofing membrane has been determined at the product end. In the subsequent construction stage, the waterproof material is generally located above the thermal insulation material and under the photovoltaic modules, and the integrated construction will take into account the integration of the waterproof layer and the support, thereby ensuring the waterproofness of the BIPV roofing system.

In the civil field, photovoltaic tiles only replace the original tiles, and the roof waterproofing still needs waterproofing membranes. In traditional brick and asphalt shingle roofs, the waterproofing of the roof is mostly undertaken by the waterproofing membrane layer under the shingles. However, photovoltaic shingles only replace traditional bricks and asphalt shingles and do not undertake too much waterproof performance. At the same time, replacing the photovoltaic tile, it will inevitably cause damage to the original waterproof layer due to the need to install support. In the photovoltaic tile installation process disclosed by Longyan New Energy, the photovoltaic tile needs to be installed on the roof waterproofing membrane recommended by the concrete tile manufacturer. Therefore, in the civil field, the use of photovoltaic tiles as roofing still requires the bottom layer of the waterproofing membrane.