Why Are Metal Sheet Roofs Leaking?

　　Why are metal sheet roofs leaking?

　　1, by the characteristics of the material itself caused by leakage hidden danger:

　　(1), the metal plate itself is large thermal conductivity, when the outside temperature changes greatly, because of the change in the environment, the temperature changes caused by the color plate contraction deformation and at the interface to produce a large displacement, so in the metal plate interface is very easy to produce leakage hidden trouble.

　　(2), in the steel structure system, because the structure itself in the temperature change, under the wind load, the snow load and so on the action, easy to occur the elastic deformation, in the connection part produces the displacement to produce the leakage hidden danger.

　　(3), special parts, because of the use of different materials, such as the daughter wall and steel connections, roof lighting belt, and other parts, due to the stress changes are not synchronized, resulting in leakage potential.

　　2, housing structural design or plate type defects caused by leakage hidden danger:

　　(1), in the fierce market competition, the construction side to undertake the task, and-flavor to reduce the cost, in order to save raw materials, in the structural design, reduce the housing slope, or even less than 1/20, resulting in roof rainwater can not be discharged in time to the gutter, so that roof water, resulting in

　　(2), due to cost factors, the current light steel housing used by the pressure type, most of the high wave of the lower plate type (effective area), and lap width less, when housing water, easy to diffuse over the plate-type lap joints, resulting in leakage.

　　(3), the lack of node design, construction units randomly choose the node, the roof of the parapet is not high enough, the roof of the pipe, the location of the exhaust duct or not enough, so that the impact of waterproof layer construction difficulties, resulting in water leakage.

　　(4), the choice of plate type is improper. The use of the type of direct tapping screws connected to the plate, even if the site treatment is very good, waterproof plastic do very well in place, due to the expansion of the Panel’s performance will appear leaking.

　　(5), enclosure part of the color plate too thin. After a period of use, the external plate corrosion or affected by temperature deformation, the gap between the plate increased, resulting in leakage.

　　3, the construction factor causes the leaking hidden danger:

　　(1), in the construction project, the roof enclosure does not pay attention to the protection, randomly trample the roof, destroyed the roof the formation even appears the crack.

　　(2), Gutter does not carry on antiseptic. Some of the construction units of the gutter anti-corrosion only brush paint or asphalt paint, use for a period of time, the gutter serious corrosion.

　　(3), Steel structure Factory housing panel because of the span too large, many cases of housing panels in the overlap process, although in the lap, such as the use of polyurethane sealant and 138900 suture nails treatment, installation is often difficult to meet the design theory standards, resulting in leakage.

　　(4), gutter transverse without slope. The production should be a certain slope, at least 0.5%.

　　(5), the key node site construction is not careful. Daughter Wall, such as the root of the yin angle is not as a circular arc or arc too small, the end edge of the coil head sealing is not strict, the tin deformation, fixed point sparse plus sealing is not good. The root of the pipe sticking out of the roof is not strict, the leveling layer around the pipeline is not high, and the waterproof layer is not enough. Insulation layer construction in the rain, exhaust slot blockage, exhaust holes set unreasonable, resulting in long-term immersion in the insulation layer.

　　The cracks in the roof are separated by the waterproof sealant and the seam side wall.