Reason analysis and prevention measures of water leakage in construction
1. Coiled material waterproof bubbling
(1) Phenomenon:
Blisters are found after the coil is laid, generally from small to large, the number and size of bubbles increase with the increase of temperature.
(2) Reason analysis:
The base layer is not dry, the surface is not cleaned, water vapor penetrates into the bottom of the waterproof layer, the base layer is not coated with the base treatment agent, the adhesive does not match the properties of the coil, the coating is uneven, and the bottom surface is not applied when laying the coil. The air is removed, and some exhaust slots are blocked.
(3) Prevention measures:
The base layer must be dry and can only be laid after passing the test by the simple inspection method; the base layer must be swept clean, the selected base treatment agent and adhesive must match the material properties of the coil, and can be used after the test is qualified; After the applied base treatment agent is dried, apply the adhesive. When the roll material is laid, the air underneath must be wiped out and rolled to compact it. It is also possible to use strip sticking, point sticking, and empty paving methods to ensure that the exhaust duct is unblocked.

2.cracks in the membrane waterproof layer
(1) Phenomenon:
The waterproof layer leaks from cracks, joint cracks and irregular cracks along the ends of the prefabricated roof panels.
(2) Reason analysis:
Blind use of coils with low elongation, no additional buffer layer and reinforcement layer on the end of the board and joint details, and wrong construction methods, such as excessively tightening when laying the coil.
(3) Prevention measures:
a. Choose coils with high elongation and durability longer than 15 years;
b. Set a buffer layer at the seam of the end of the prefabricated roof panel, and the width of the dry-laid coil is 300mm. It is not advisable to stretch the coil too tightly. In summer, the construction should be relaxed before laying.
When there are cracks in the waterproof membrane, use a cutting machine to cut along the regular crack line. If there is no split seam in the base layer, the seam should be cut, the seam width is 20mm, the seam is filled with flexible sealing paste, and a 200mm wide roll of material is laid along the seam as a buffer layer, and then a 350mm wide roll is fully glued The treatment methods for the detailed cracks of the waterproof layer and joints are the same as above.

3. Leaking at the root of the parapet
(1) Phenomenon:
The waterproof layer is hollowed and cracked along the inner corner of the parapet wall, cracks in the parapet masonry, cracks in the top, the gable is pushed out of the wall, and rainwater pours into the inner wall from the gap.
(2) Reason analysis:
The leveling layer, rigid waterproof layer, etc. are directly close to the parapet wall during construction, leaving no splitting joints. The long parapet masonry does not have expansion joints. Under the action of temperature difference, the gable and parapet walls are cracked; the roots of the parapet wall are not Do the arc according to the regulations, and the waterproof layer of the rolled material is not used as the buffer layer according to the regulations, and the end of the coil is not sealed well, causing cracks, opening and water leakage.
(3) Prevention measures:
When constructing the roof leveling layer and rigid waterproof layer, a 30mm split seam should be left at the joint of the parapet wall, and flexible sealing paste should be embedded in the seam; the internal corner powder at the root of the parapet wall forms an arc, and the height of the parapet wall is greater than 800mm. Leave the groove, the end of the coil should be trimmed and pressed into the reserved groove. After nailing, the groove should be filled tightly with cement mortar or sealing material. When the height of the parapet wall is lower than 800mm, the ends of the coiled material are directly laid on the top surface of the parapet wall, and then reinforced concrete is used for topping.
The roof leveling layer or rigid waterproof layer is close to the parapet wall. When there is no split seam, a 20-30mm wide slot should be cut along the parapet wall and cleaned. The slot is filled with flexible sealing paste, and the parapet wall has cracks. , It must be repaired with grouting materials. For example, when the parapet of the gable has protruded from the wall, it must be removed and rebuilt. The opening of the coiled material should be repaired and sealed tightly.