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Photovoltaic installation | Waterproof design of roof distributed photovoltaic project!
- May 14, 2018 -

Photovoltaic installation | Waterproof design of roof distributed photovoltaic project!

With the rapid development of rooftop distributed photovoltaics, good roofs are becoming more and more sought after.

However, photovoltaic projects on existing rooftops will encounter many problems, especially in the reconstruction and expansion projects, which need to have a good connection with the original main structure in order to ensure the performance and waterproof sealing performance of the photovoltaic power generation system.

Metal roof photovoltaic power generation system


Metal roofing systems include: standing seam aluminum-magnesium-manganese metal roofing systems, vertical snapping systems, flat locking roofing wall systems, secondary roofing systems, angled roofing systems, concealed roofing systems. There are a variety of metal roofs, and PV arrays are installed in various ways.

To install photovoltaic systems on metal roofs, metal roof solar photovoltaic support systems are connected to roofs through various connectors. Under normal circumstances, for the stand-up seam aluminum-magnesium-manganese metal roofing system, vertical occlusal system, corner-roofing roofing system, as long as the waterproof layer of the metal roof is not damaged, pay attention to the construction of the PV array, take measures to protect the roof, waterproof the roof. The building function will not be destroyed. To solve this kind of waterproof seal problem, it is to solve the waterproof problem of metal roof.

■ Project Example:

Through the inspection of the site and the communication with the owners, after fully understanding the situation of the on-site roof, the reasons for the leakage of the roof are summarized as follows:

1. The corrosion of the original roof panel connection position;

2. There is no fixed access to the roof. The walking of the maintenance personnel can easily cause damage to the local board and cause water leakage.

3. The original lighting skylights did not do a good job of waterproofing, and local leaks were serious;

The following causes can be solved for the above causes of water leakage:

1. Treatment of rusted locations

1) Pretreatment:

Before the construction of the metal roof, carefully inspect the entire roof for leaks and pretreat it to ensure that the metal roof is firm, clean, free of rust, debris, and dust. If the conditions are not met, the following treatment shall be taken:

A. Replace rusted firmware and add firmware in place;

B. The rusted area is polished with rust-reducing sandpaper until the metal color appears, then a layer of primer is applied.

C. Remove debris, dust and other dirt;

2) Apply waterproof treatment to the rusted position of the roof and use a waterproof coating for spraying.

Metal roof lap:

A layer of base paint is applied to the lap joint of the metal roof. When it is still wet, a 15 to 20 cm wide sewn polyester fabric is embedded in it, and then the base fabric coating is fully impregnated into the woven polyester fabric from the top to the full. dry.

Build a walkway:

After solving the roof leakage, special inspection and maintenance passages will be made to avoid any subsequent damage to the roof.

Specifically, the access channel is fixed on the rib protruding from the metal roof panel, and a metal grille is provided to provide access for maintenance personnel. Avoid walking around and causing damage to the roof.

2. For the treatment of roof protrusions

1) Protruding metal roof (such as chimney, vent, fan mouth, etc.): cut the size, shape of the sewing fabrics suitable for sewing, and cut according to technical requirements, a layer of base coating around the protrusions, the cutting A well-stitched polyester fabric is laid on it, and the woven polyester fabric is fully impregnated with the base paint from above to ensure no blistering or wrinkling.


  • Metal roofing and lighting roof junction.

2) Metal Roofing Firmware: A 10 cm x 10 cm stitched polyester cloth was treated in the same manner as above.


Original metal roof lightning protection zone

3) Metal roof gutters: The gutters are lap joints, and the water outlets, etc., are first partially waterproofed with a metal roof, and then a layer of paint is applied to a larger waterproof area, and a woven polyester fabric is laid while it is still wet. From the above, the woven polyester fabric was fully impregnated with the slurry until it was completely dry. At least 12 hours later, a further layer of slurry is applied.


Combination of metal roof and drainage ditch

3. Mounting method of PV module bracket

The metal roof is a metal roof with interlocking structure. As shown below, the supporting point of the roof is on the rib of the roof panel. The bracket we designed is fixed on the ribs of the roof panel by metal clips. It is not only without any Perforation, and can make the roof panel bite more firmly, can solve the leakage problem caused by roof panel bite loose.


Metal roof lap


Battery panel in metal roof installation


3D illustration of battery panel mounted on metal roof

Photovoltaic lighting top


Photovoltaic lighting roof is the performance of photovoltaic building integration. It is the top of the building with lighting function made of double-glass photovoltaic module material, with power generation function and building function. Photovoltaic lighting roof photovoltaic components will bear their own various loads through the silicone structural adhesive to the aluminum alloy sub-frame, and then through the pressure block and self-drilling self-tapping screws to transmit the sub-frame line load to the beam and the column. At the same time, for the outdoor, silicone structural adhesive also played a sealing role. Therefore, the correct selection of silicone structural adhesives, reasonable node design, and control of construction quality are the key to ensure the safety of photovoltaic roof lighting structures. The airtightness and watertightness of the lighting roof are mainly depended on the silicone sealant to ensure that the silicone structural adhesive is comparable to human teeth, while the silicone sealant is comparable to human lips, cold and indifferent.

Project Example:

Photovoltaic lighting installation:

1. Measure payoffs, conduct necessary review based on the axes, elevations and construction records of the ball joints transferred by the main construction unit, determine whether the ball joints of the grid are applicable, perform comprehensive measurement and payoff according to the lighting layout, and determine the top of the light. Install the elevation of the axis, and promptly collate and submit the measurement data to the relevant parties such as the owner for confirmation; feedback the designers of the bias data of the embedded parts, and submit the processing opinions to the owner for confirmation;

2. Remove the ointment from the ball joint and install the support on the ball joint;

3. Beam installation;

4. The installation of the glass surface layer includes surface layer installation, cleaning, and glue application.

The daylighting roof is a single slope lighting top with a drainage slope of 3%. The double glass photovoltaic module is first placed in the design position, and the double glass assembly is fixed and stuck on the aluminum rail by double-side pressing blocks and self-drilling self-tapping screws. The gap between the surface layers of the glass photovoltaic modules is filled with foam sticks and a weather resistant sealant to form a decorative surface layer. After the surface layer has been installed, glue can be arranged. The glue is firstly glued on the two sides of the glue seam to protect the tape, and then the foam strip is evenly filled into the glue gap. The surface of the foam strip should be controlled between 5-7mm from the surface of the finish to ensure the sealant Thickness, clean the adhesive interface with clear liquid, then use the glue gun in the same direction to evenly inject the sealant into the glue gap, and immediately use a rubber tube or a gray knife to level off, remove the protective paper, avoid long time pollution . The use of glue is an important part of testing the success of the installation, not only the appearance of the pen, but also directly affects the see-through function of the roof. When weathering, we must also pay attention to the weather conditions, prevent rain, avoid high temperature and low temperature operation below 5 degrees, to ensure the quality of glue, and ensure uniform thickness of the seam, the surface is beautiful and smooth. The installation opening must be carefully protected by water-proof pads and supports to ensure that the design requirements are met and the opening and closing are flexible.

5. After the cleaning and inspection of the installation surface layer is completed, the net external finishes shall be promptly cleaned and submitted to the relevant parties such as the owner for inspection and acceptance. After the project is completed, it is necessary to organize the clean-up work before acceptance.


Hidden frame lighting cross-section node schematic


Hidden frame lighting top vertical section node schematic

Photoelectric curtain wall

Considering the shading and the processing limitations of photovoltaic modules, the current photovoltaic curtain wall is dominated by hidden frame curtain walls. In the hidden frame curtain wall project, whether it is the structural assembly of the surface layer, or to achieve the airtightness, watertightness and other architectural functions of the curtain wall, it mainly relies on silicone rubber. Silicone structural adhesives for photovoltaic curtain walls bond photovoltaic modules to supporting structures. Silicone structural adhesives are specifically designed for the assembly of architectural curtain wall structures. Can be easily extruded for use under normal climatic conditions. Silicone structural adhesives have high strength, can withstand large loads, and are resistant to aging, corrosion and fatigue. Silicone sealant This material has the characteristics of high temperature resistance, ultraviolet radiation resistance, rain resistance and no aging. It is the sealant with the longest service life. It is therefore called weatherproof adhesive. Therefore, it is very important to design and use silicone structural adhesives and silicone sealants rationally.


Hidden Frame Curved Wall Cross Section Node Diagram


Hidden frame curtain wall vertical section node schematic

Sum up

According to reports, the combination of photovoltaic square arrays and buildings is different. Photovoltaic building integration can be divided into two categories: one is the combination of photovoltaic arrays and buildings, such as installing photovoltaic systems on concrete roofs and metal roofs. The other category is the integration of photovoltaic arrays and buildings. Such as photoelectric tile roof, photoelectric curtain wall and photovoltaic roof.

Most of the photovoltaic power generation projects currently under construction are installed on buildings that have already been built, so there is an urgent need to study the problem of waterproof seals between the newly-increased photovoltaic system support structure and the original structure. This article briefly summarizes the commonly used methods of waterproof sealing of centralized photovoltaic systems and discusses with everyone. Regarding how to solve the problem of waterproof sealing in the building photovoltaic power generation system, we are paying attention to the protection and repair of the original building and at the same time we solve the waterproof sealing treatment with the original building.