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How to waterproof in the process of distributed PV design and installation?
- Aug 01, 2018 -

At present, with the strong support of national and local government policies, distributed photovoltaic power generation systems have become more and more widely used, which has become an important development direction in the future.

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However, due to the market introduction period of distributed photovoltaic power generation, the quality of design and construction is uneven. The waterproof problem of photovoltaic roof is easy to be neglected. Once the waterproof layer is damaged or even waterproof layer is installed, it is easy to leak, which not only affects the photovoltaic system. More affect the normal use of the user's house. So how can the roof be waterproof?

The general principle of roof waterproofing treatment is: proper conduction should not be blocked, that is, to ensure that the node treatment in the rainstorm water can be smooth let the water fall off and ensure that the roof does not leak.

For perforation to destroy the original roofs, we must do things according to local conditions and do different treatments according to different situations.

1. Waterproof of concrete flat roof

For new buildings with flat concrete roofs, bolts should be embedded in the design and roof waterproofing should be done according to the conventional practice. For the existing building, when setting up the base of the photovoltaic component, the waterproof layer should be laid on the upper part of the base and the metal burial parts, and the sealing treatment is done around the anchor bolts. The waterproof layer is filled with waterproof sealant. In addition, additional waterproof layer can be added under the base. Even if the roof is leaked at the top of the base, the rain will not come to the ground. Up to the structure layer.

2. Use of chemical anchor bolts

For existing buildings with concrete flat roof, if chemical anchor bolts are used to fix the support, the thickness of protective layer or surface layer should be confirmed first. For precast slab roof with large bearing capacity per unit area, concrete layer of certain thickness can be poured on the roof, and chemical anchor bolts can be used to fix the support after solidification.

For overlying roof, the hole depth should be confirmed. After the chemical anchor bolts are fixed, the position of the bolts through the tiles should be well treated with waterproof sealant. Chemical anchor bolts have the advantages of large bearing capacity, anti-fatigue, anti-aging, and so on. They have no expansion force on the matrix and do not generate extrusion stress, so they will not adversely affect the roof waterproof.

3. Waterproof of metal roofs

For metal roofing, the steel structure of the photovoltaic system should be penetrated through the original waterproof layer and the compression steel plate, fixed on the main steel structure of the building, and then referring to the waterproof method of metal roofing, to carry out the steam insulation, heat preservation and waterproof treatment. The main points of construction are to rust, seal, and brush the waterproof coating on the base and the periphery.

The local leakage of metal roofs should be coated with high quality neutral weatherproof sealant, and the color steel plates with serious local corrosion need to be replaced before the installation of photovoltaic components.

Therefore, the installation design of PV modules should consider not only sunshine and shadow, but also bearing, drainage and waterproofing.