Roof waterproofing is a common quality problem in building engineering, and it has not been solved well for many years. At present, rigid and flexible waterproof methods are widely used. Rigid waterproofing is easy to crack and seep due to temperature difference strain; Flexible waterproof, mostly asphalt, linoleum and other organic materials, easy to age, short life. In recent years, although a variety of new waterproof materials have emerged in an endless stream, their durability needs to be further tested due to their high price and lack of construction experience. So at present, relatively cheap materials are mainly used.
The combination of rigid waterproofing and flexible waterproofing can theoretically improve the waterproofing of the roof. However, in the actual construction process, there is more or less a lack of attention to the underlying rigid waterproof layer, which makes the rigid waterproof layer crack, bulge or leak, making the rigid waterproof layer useless, and the flexible waterproof layer also has its own shortcomings, so "double insurance" can not effectively prevent roof leakage. This paper discusses several measures of waterproof treatment design and construction quality control of building No.4 in residential engineering.
The basic structure layer of rigid waterproof roof should be cast in situ as a whole. When precast reinforced concrete hollow slab is used, the roof slab should be compacted with 0 # mortar first, and then carefully compacted with C20 fine stone concrete. The compacted concrete should be mixed with micro-expansive agent, and each joint should be compacted twice. When the joint width of roof plate is greater than 40mm, structural reinforcement must be set in the joint, and the joint at the plate end should be sealed. After the initial setting, it should be cured for one week, and the drainage should be checked for leakage. First, the setting and practice of frame joints should be set at the supporting end of the roof panel, the corner of the roof, the junction of the waterproof layer and the protruding roof, and should be aligned with the joint of the roof panel, so that the cracks of the waterproof layer caused by temperature difference, concrete shrinkage structure deformation and other factors are concentrated at the frame joints to avoid cracking of the panel. The spacing between frame joints should not be too large. When it is more than 6m, a V-shaped frame joint should be set in the middle, and the depth of the frame joint should run through the thickness of the waterproof layer. When the frame joint is also used as an exhaust duct, the frame joint can be widened appropriately and an exhaust hole can be set for exhaust. When oil, asphalt and linoleum are used as the waterproof layer of the roof, linoleum with a width of 200 mm ~ 300 mm should be added to the frame joints, and asphalt glue should be pasted on one side, and ointment should be embedded in the frame joints. Second, the roof leveling layer practice The roof adopts the combination of building slope finding and structure slope finding. First, find the slope according to the structure of 3%, then use 1: 6 cement slag or cement expansive concrete stone to find the slope on the structural layer, and then make a 25mm thick cement mortar leveling layer. When looking for a slope in a building, we must find the flooding slope and the direction of water flow. Straighten, dot, pat, and the thickness of the drainage ditch with fishing line between the highest point and the drainage ditch shall not be less than 30 mm. When pouring, it must be rolled with a roller and a ruler to make it dense. Third, the practice of roof insulation layer here to emphasize the importance of roof insulation layer. In areas with heavy acid rain, high humidity and strong corrosiveness, the common practice of general construction units is to brush cold priming oil on the leveling layer as an isolation layer, and then pour a rigid waterproof layer. In order to ensure that the roof does not leak during the three-year warranty period, two cloth and three oil waterproof layers are made on the rigid layer. When the project is accepted, what Party A sees is the black oil on the roof, but actually the ointment is applied to the surface, which is easy to age and has a short service life. After three years, it will be used to fill the loophole. In order to avoid this situation, in the construction, adjust measures to local conditions, learn from each other's strong points, and make this waterproof layer of two cloth and three oil coils between the leveling layer and the rigid layer, which not only plays the role of isolation layer, but also prevents the ointment from aging and waterproofing.
In the construction of coiled material waterproof layer, the following points should be paid attention to:
(1) It is required that the base treatment agent be thin and uniform on the base. Generally, after drying, the coil can be laid without sticking hands. (2) Generally, the waterproof layer of coiled materials should be laid parallel to the roof at the lowest elevation of the floor, so that the coiled materials overlap in the direction of water flow. When the roof slope is greater than 10%, the coiled material shall be laid perpendicular to the roof. (3) Paving method: peel off the isolation paper on the spine of the coil and stick the coil on the surface of the base. Keep the long side of the coil 50mm and the short side 70 mm. It is required that the coil be naturally relaxed and not pulled too tightly. After the coil is laid, it shall be fully compacted with a flat vibrator, and the vertical part shall be compacted with a rubber hammer. (4) Lap bonding of coiled material: After the coiled material is compacted, uncover the lap joint, and evenly apply lap bonding agent with a paint brush. The two bonding surfaces of the coil seam can be bonded after being uncovered and dried for a period of time, and then compacted with a rubber hammer to avoid water leakage; (5) The construction temperature of waterproof layer should be above 5℃.
Four, the practice of steel mesh fine stone concrete rigid waterproof layer In the concrete waterproof layer, two-way Ф 5 @ 200× 200 cold-drawn steel mesh should be set up and disconnected at the frame joints. In order to enhance the rigidity of the waterproof layer and the integrity of the plate, the layout of steel mesh in the waterproof layer should be in the upper part as far as possible. Because the surface of the waterproof layer is greatly affected by temperature difference, cracks are prone to occur, and the influence of surface carbonization on steel bars should be considered at the same time. Therefore, the protective layer thickness of steel mesh should not be less than.
The strength grade of fine stone concrete waterproof layer should not be lower than C25, and mechanical mixing and vibration should be adopted, and the water cement ratio of concrete should not be greater than 0? 55, cement label should not be less than 425 #. The thickness of concrete should not be less than 40mm, too thin, the concrete loses water quickly, the cement can not be fully hydrated, and the impermeability of concrete is reduced. Attention should be paid to the surface treatment of the waterproof layer, the thickness of the panel should be consistent, the drainage slope should meet the specification requirements, and the concrete should be calendered for the second time after water is collected to cut off and seal the capillaries in the concrete and improve the impermeability. When plastering the surface, it is forbidden to sprinkle water, add cement slurry or sprinkle dry cement on the surface to prevent cracking and peeling and reduce the waterproof effect.
Waterproof concrete can be cured after pouring 12 hours to 24 hours, and the covering time shall not be less than 14 hours. No one is allowed at the beginning of curing, and concrete curing is the most important last process of fine stone concrete waterproof layer. Poor curing will lead to early dehydration of concrete, which will not only reduce the strength of concrete, but also lead to sand formation on the surface of internal cracks of concrete due to drying shrinkage, greatly reducing the impermeability. V. Node and detail construction practices Improve node practices and strengthen the protection of finished products. Unreasonable joint structure or rough construction is often the main reason for joint leakage. In the node part, the rigid-flexible combination method should be adopted, and all nodes should be filled with sealing materials, which is especially important for rigid waterproof layer.
The junction of rigid waterproof layer with gutter and eaves gutter should be slotted and sealed with sealing paste.
At the junction of rigid waterproof layer and wall on both sides of deformation joint, 30mm seam should be left, and the seam should be filled with sealing material. The flashing place should be supplemented by coiled material or coated waterproof layer, and there should be a gap at the junction between the pipeline protruding from the roof and the waterproof layer, which should be filled with slope protection first and then sealing material.
The nozzle of the downspout shall meet the following requirements: (1) The buried elevation of the downspout shall consider the thickness of additional layer and flexible sealing layer added when the downspout is waterproof. And the increase of drainage slope; (2) Within 500mm in diameter around the mouth of downspouts, the slope shall be not less than 5%, and waterproof coating or sealing coating shall be applied, with a thickness of not less than 2mm. The contact between the impinges koubei and the grass-roots level shall have a groove with a width of 20mm and a depth of 20mm, and the sealing material shall be embedded.
30mm gap should be left at the junction of rigid waterproof and gable and parapet, and filled with sealing material.
The main causes of parapet cracking are related to temperature change, construction quality, environmental impact and design structure. Because the parapet cracks and leaks, the roof panel is not tightly plugged, which will lead to leakage in the indoor corner and affect other parts. So stick a brick around the parapet, the horizontal direction is close to the vertical elevation direction of the outer side, and then do slope prevention inward, which can avoid the side cracking of the parapet for too long. Six, the practice of ventilation and thermal insulation layer
The common practice is to use 100 # cement standard brick to build brick piers, and the height of the brick piers is 180mm, which is 240mm according to the depth of the roof. When the depth of the overhead roof is greater than 15m, a ventilation bridge should be set at the roof ridge, and the brick pier should be covered with thick? 30mm, 600mm×600mm thick insulation board, then make a layer of 20 mm 1: 2 cement mortar on the insulation board, lift the slurry and polish the clean surface, cut the frame joints with a cutting machine according to the specifications of 400mm×400mm, and then fill the frame joints with solid ointment, and spread 300mm two cloths and three oils on the surface.
To sum up, it is not difficult to see that the quality of waterproof roof is closely related to design and construction. Due to the negligence of design or the failure to carry out the construction as required, many quality hidden dangers will be left for the roof waterproofing project, which cannot be remedied. Therefore, in order to improve the quality of waterproof roof, it is necessary to double check the design and construction.