The general principle of roof waterproof treatment is: it is better to guide rather than block, that is, to ensure that the node treatment can smoothly let the water drain off when the water is accumulated in rainstorm, so as to ensure that the roof is not leaking. Therefore, in the design process, the first step should be to ensure that the bracket base is not arranged perpendicular to the drainage direction and does not hinder the drainage of rainwater from the roof. In addition, when installing the photovoltaic system directly on the existing roof during construction, the base is not related to the structural layer of the original roof. Therefore, to ensure the safety of the structure, it is necessary to ensure that the base is placed smoothly and neatly, and measures need to be taken to fix it to avoid overturning, sliding, and other phenomena. Due to the lack of relationship between the base and the structural layer, it is difficult to install additional waterproof layers. Therefore, efforts should be made to preserve the original waterproof layer of the roof to prevent leakage.

For situations where drilling holes is necessary to damage the original roof, it is necessary to adapt to local conditions and make different treatments according to different situations.

1. Waterproofing of concrete flat roofs or villa concrete sloping roofs: For newly built buildings with concrete flat roofs or villa concrete sloping roofs (covered with tiles), bolts should usually be embedded during design and roof waterproofing should be done according to conventional practices.

For existing buildings with concrete flat roofs or villa concrete sloping roofs (covered with tiles), the roof structure should be confirmed first. When connecting the photovoltaic module base to the structural layer, there are weak waterproof links around the metal embedded parts at the top of the base. If not handled properly, rainwater can easily seep into the structural layer from around the bolts of the embedded parts, causing corrosion to the load-bearing steel bars of the structural layer and posing a safety hazard. Therefore, when setting up the photovoltaic module base, the waterproof layer should be laid on the upper part of the base and metal embedded parts, and sealed around the anchor bolts. The waterproof layer should be filled with waterproof sealant to isolate the rainwater infiltration path. In addition, an additional waterproof layer should be added to the lower part of the base. Even if there is leakage at the top of the base, rainwater will not reach the structural layer.

2. Waterproofing of metal roofs: For metal roofs, the steel structure of the photovoltaic system needs to penetrate the original waterproof layer and pressed steel plates, and be fixed on the main steel structure of the building; Refer to the waterproofing method for metal roofs and carry out vapor isolation, insulation, and waterproofing treatment. The focus of construction is to remove rust, seal, and apply waterproof coating to the base and periphery. Local leaks on metal roofs should be sealed with high-quality neutral weather resistant sealant; For locally corroded color steel plates, they need to be replaced before installing photovoltaic modules.

1) For trapezoidal color steel plate ribs: Color steel tile photovoltaic brackets are usually connected to the color steel plate from the side or top through self tapping bolts. Self tapping bolts must be equipped with matching weather resistant and waterproof gaskets, and after fixing the self tapping bolts, high-quality neutral weather resistant sealant must be applied to the screw area.

2) For cases where cable sleeves pass through roof slabs: there are practices available in the existing national standard atlas. In design and construction, it can be selected according to the specific situation of the actual project.

3) For the case of cables passing through the roof slab: Detai cover sheets can be used for waterproofing. Detai cover is a type of roof waterproofing structure, often used on roofs with colored profiled steel plates. It has good physical properties and chemical corrosion resistance, and can overcome problems such as water leakage from rigid waterproofing materials.

Waterproofing treatment at the drilling point on the roof

For existing buildings with concrete flat roofs or villa concrete sloping roofs, if chemical anchor bolts are used to fix the brackets, the thickness of the protective layer or the surface layer used should be confirmed first. For prefabricated floor roofs with large load-bearing capacity per unit area, a certain thickness of concrete layer can be poured on the roof in situ, and after solidification, chemical anchor bolts can be used to fix the brackets. For sloping roofs covered with tiles, the drilling depth should be confirmed. After fixing the chemical anchor bolts, the position where the bolts pass through the tiles should be well treated with waterproof sealant. Chemical anchor bolts have high load-bearing capacity, are resistant to fatigue and aging, and some models can withstand dynamic and impact loads; There is no expansion force on the substrate and no compressive stress is generated, so it will not have adverse effects on roof waterproofing.

During the construction process of distributed photovoltaic power generation systems, there may be a risk of roof rainwater leakage, which should be taken seriously. From the on-site survey stage to the detailed design stage, it is necessary to make a sufficient estimation and demonstration of the potential leakage risks of the roof in the future. Any possible points of rainwater leakage should be thoroughly investigated, and simple and effective technical methods should be used as much as possible for waterproofing treatment; During the construction phase, it is important to avoid secondary risks to roof waterproofing.