The research of waterproof engineering technology in China started late, the investment is not enough, and the theory is not very mature. The common quality problems of waterproof engineering, especially leakage, have been puzzling engineers and users. In the daily complaints about housing quality, the proportion caused by housing leakage remains high. In the early 1990s, the former Ministry of Construction investigated the quality problems of existing buildings around the country. Statistics show that nearly 40% of the houses were found to have different degrees of leakage in the roofing project. House leakage is a small problem in a short time, but if it is not dealt with in time, it will have a direct impact on the use function and life of the building. Judging from the service life of a building, a long time may even bring security risks and endanger the residential safety of residents during the normal service life of the building. With the continuous improvement of users' requirements for living quality, the state has successively issued relevant standards and specifications for roofing and basement engineering, and revised them several times. On the basis of summing up experience, combined with the requirements of new materials and new construction technology, the corresponding construction standards and specifications are put forward. Waterproof engineering has been improved from using linoleum waterproofing in the past to designing waterproof layer according to the functional requirements of the building and selecting waterproof materials according to the specific environment. In practice, we mainly do "four controls" to improve the engineering quality, that is, control the quality of waterproof materials, control the design of waterproof structure, control the construction quality of waterproof workers, and control the whole process management from construction to use. Connecting with the supervision project, this paper expounds how to do well the quality supervision work of waterproof project.
Second, the basic situation of the project
A project is a commercial and residential building, with a total construction area of 32,000 square meters, one basement and 22 floors above ground, with a building height of 72 meters. The structural form is frame shear wall structure, and the foundation structure is pile valve plate foundation. Waterproofing works of this project are mainly divided into roof waterproofing, basement waterproofing, exterior wall waterproofing and rooms with waterproof requirements such as kitchen, bathroom and washroom. Among them, self-adhesive polymer modified asphalt waterproofing membrane is used for roof, waterproof concrete and SBS modified asphalt waterproofing membrane are used for basement exterior wall and ground, waterproof mortar is used for exterior wall, and polymer cement waterproof coating is mainly used for indoor waterproofing.
Third, do a good job of "five passes" to improve the quality of waterproof engineering.
The quality of building waterproof engineering is influenced by many factors. The improvement of its quality is a systematic project, which is related to the use of materials, design details and the quality of workers' construction. It not only involves the waterproof project itself, but also interweaves with other sub-projects, so it is necessary to strengthen the overall arrangement. As a supervision engineer, we should do the following "five customs".
1. Pass the good materials into the construction site. At present, there are many kinds of waterproof engineering materials on the market, and there are also many inferior and unqualified products. At the same time, the emergence of new materials has also increased the difficulty of supervision. Waterproof engineering materials that should be paid attention to in supervision should have qualified quality certification documents, and the product quality should meet the corresponding standards and technical indicators after being certified by the designated quality inspection department. After the waterproof engineering materials enter the construction site, the construction unit shall take samples for a second interview in accordance with the regulations, and submit an inspection report. The supervision engineer shall close the materials, conduct on-site sampling on the appearance quality, specifications and physical properties of waterproof materials according to the requirements of relevant specifications, and check the factory certificate and quality inspection report of the products. Waterproof materials that have not been reinspected on site and obtained inspection reports shall not be used in waterproof projects.
2. Ensure the qualifications of construction units and workers. Waterproof engineering belongs to the category of professional contracting. According to the regulations of the Ministry of Housing and Urban-Rural Development on the qualification management of the construction industry, waterproof projects should be subcontracted to units with waterproof professional contracting qualifications, and workers engaged in waterproof project construction should obtain employment certificates issued by the construction administrative department. Regular units and construction personnel are the guarantee of engineering quality, so supervision engineers should pay attention to reviewing whether professional contracting enterprises and personnel have corresponding qualifications before waterproof engineering construction.
3. Do a good job in the preparatory work for the construction. Three preparations that supervision engineer should pay special attention to before waterproof engineering construction.
(1) The construction unit must abide by the basic norms and regulations related to waterproof engineering and overcome the common fault of replacing the special construction scheme of waterproof engineering with the construction organization design scheme or design drawings. Before construction, according to the design requirements and technical requirements of waterproof engineering, combined with the actual situation of the project, a targeted waterproof construction scheme or technical measures should be prepared, and reviewed and approved according to relevant regulations. The supervision unit shall prepare detailed supervision rules for waterproof engineering according to the special construction scheme.
(2) Before construction, the person in charge of project construction shall make technical disclosure and safety disclosure to the operation team, and go through the signing formalities. The focus is on the location and grade of waterproofing, the use and characteristics of waterproofing materials, construction procedures and specific practices, detailed treatment of key parts, quality assurance measures and other disclosure work.
(3) Preparation of construction foundation. The quality of construction base is very important to ensure the construction quality of waterproof engineering. In order to clarify the responsibilities and improve the quality of waterproof engineering construction, before the waterproof engineering construction, the supervision unit shall organize the general contractor and waterproof professional contractor to inspect and accept the grassroots according to the relevant specifications. For example, for the roof, the joint between the base and the roof and the corner between the base and the roof should be curved and straight. The leveling layer should be smooth and calendered, and there should be no looseness, sanding, peeling, honeycomb and water accumulation. When the grass-roots do not meet the requirements of waterproof construction, the professional contractor shall put forward it in time, and the general contractor shall carry out rectification. The waterproof layer construction can only be carried out after the handover procedures meet the requirements.
4. Pass the joint review of design drawings. The task of building waterproof engineering design is to scientifically determine the waterproof design scheme, comprehensively consider the advanced technology and economic rationality, and take reliable measures to ensure that the waterproof engineering can be used normally within a certain service life without leakage and ensure the engineering quality. However, due to the designer's misunderstanding of the specification, he doesn't know much about the performance and use conditions of the new waterproof material, and the phenomenon of design defects is common. Therefore, it is particularly important to reduce unreasonable waterproof design through the joint review of drawings. During the joint hearing, the supervision engineer should put forward opinions on the waterproof project from the following points: first, whether the waterproof material is selected reasonably and correctly according to the actual needs of the project; The second is whether the design of waterproof protective layer is fully considered, and the third is whether it is convenient for construction and conducive to quality control.
5. Coordinate with other branch projects. Waterproof project is an important branch project, and its particularity determines that it is closely related to other professional projects and affects each other. A, before the formal implementation of waterproof engineering, need to provide civil working face, such as grassroots cleanliness, flatness, moisture content, etc., should comply with the requirements of relevant specifications. Second, all kinds of pipes need to pass through the waterproof layer in the engineering installation and decoration project, and the crossing parts need special treatment. Three, after the completion of the waterproof layer construction, before the completion of the protective layer, should do a good job in the protection of the waterproof layer, avoid materials, tools and other items piled up on the waterproof layer, causing damage to the waterproof layer.
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Therefore, to coordinate and handle the relationship between waterproof engineering and other projects, supervisors need to focus on the following issues:
(1) Waterproof engineering is characterized by a wide range of points, complicated working procedures and many overlapping operations. Before construction, the supervisor urged the construction unit to make overall arrangements for the operation surface and coordinate its implementation.
(2) Safety protection of crossover operation: In the later stage of the project, all types of work will enter the site at the same time, and professionals of multiple types of work will work in the same plane and vertical working face at the same time. Supervision engineer should pay attention to check whether the three-dimensional protection work has been done well.
(3) Civilized construction measures: During the construction of waterproof project, tools and materials stacked in indoor site should be neatly stacked, and waste and garbage should be transported to the designated place in time.
Four, improve the quality of waterproof engineering monitoring points
Due to the particularity of its technology, it is very difficult to mechanically construct waterproof engineering. At present, the waterproof construction of buildings is still mainly manual operation. Therefore, mastering the construction technology of key nodes is the key to reduce common quality problems, otherwise leakage may occur with slight negligence, and these nodes are also the focus of quality monitoring by supervision engineers.
(a) roof waterproof monitoring points
The roof of this project adopts self-adhesive polymer modified asphalt waterproofing membrane for waterproofing, which has the characteristics of good waterproof performance and convenient and fast construction. When in use, the release paper pasted on the back of the waterproof coiled material is directly torn off, and the coiled material and the base layer can be pasted by a layer of high-performance adhesive at the bottom of the coiled material.
1. Before laying the waterproofing membrane, in order to improve the bonding performance between the base and the waterproofing membrane, the usual practice is to coat a layer of base treatment agent first. Brush corners and details first, and then brush a large area. The supervision engineer mainly checks whether there is brush leakage and unevenness.
2. Before laying the waterproof layer of bedding face self-adhesive coiled material, the details of the roof, such as parapet, yin and yang angle of the building, various exhaust pipes and rain outlets, etc. , arrange someone to paste additional waterproof layer according to relevant specifications and design requirements. Supervisors need to strengthen the inspection of the bonding quality of the additional layer of the detailed node coil, and only after passing the inspection can the next stage of large-area coil laying be carried out. Before paving the bedding face coil, it is necessary to make elastic thread and trial paving, mainly to determine the overlapping position and paving direction. When determining the paving direction, supervisors should pay attention to the roof slope, which is parallel or vertical to the roof ridge according to different slopes. When laying the shop, peel off the lower surface isolation film while gradually unfolding the coil, and lay the shop according to the played baseline. At the same time, the exhaust must be rolled from the inside out, and the coil should be compacted. The overlapping width of the long and short sides of self-adhesive waterproofing membrane should meet the requirements of relevant specifications. The overlapping width of the long side and the short side is 80 mm.
3. Waterproof treatment of high-low span deformation joints. First, check that the flooding height of the deformation joint should not be less than 250mm, and the height of the high-span wall groove should not be less than120 mm. The deformation joint should be filled with polystyrene foam, the upper part should be filled with gasket material, and then the coil should be covered. Self-adhesive coiled material waterproof layer should be laid at the top of low-span wall. Additional waterproof layer should be set at the top of the deformation joint, and the coiled material should be bent around the U shape in the joint to compensate for the expansion caused by the deformation of the building.
(2) the basement waterproof monitoring points
Waterproof concrete is used in this project, and its construction technology is the same as that of ordinary concrete projects. However, due to the waterproof project, there are several points that cannot be ignored in the construction process:
1. Because the basement is located in a relatively humid soil environment, if iron pieces pass through the concrete wall, it is easy to form a water seepage channel in the concrete due to the corrosion of iron pieces. Therefore, special treatment methods should be adopted to fix the basement formwork, and supervisors should pay special attention to avoid iron pieces directly passing through the waterproof concrete structure layer. The way to avoid directly passing through the concrete is to weld the water stop ring on the embedded casing or bolt. For the use of embedded casing to fix the formwork, after the formwork is removed, pull out the bolts and block the casing with expanded cement mortar. If the formwork is fixed by bolts, the exposed parts at both ends of the bolts shall be removed after formwork removal.
2. The correct retention of protective layer of waterproof concrete reinforcement in basement is more important than general concrete engineering. Therefore, the thickness of reinforced protective layer should be designed in strict accordance with the design requirements. The method is to use fine stone concrete or cement mortar with the same mixture ratio to make a cushion block, and put steel bars on it. The protective layer thickness of waterproof concrete reinforcement at the water front is generally not less than 35mm.
3. Construction joint lien. If there are no special circumstances, the waterproof concrete in the basement should be cast continuously, leaving as few or no construction joints as possible. Especially, it is not advisable to leave construction joints on the roof and floor. The horizontal construction joint of the wall should be left at a position more than 300mm above the bottom surface to avoid bending distance and horizontal shear force. There are four kinds of horizontal construction joints: concave joint, convex joint, high-low joint and flat joint, and the flat joint should be provided with water stop pieces.
4. After the waterproof concrete structure is completed, we should pay close attention to the construction of the next working procedure and backfill and tamp the foundation pit in layers in time. After backfilling, the slope of apron around the building should be done in time to protect the foundation pit from the invasion of bottom water. All reserved holes and embedded parts of waterproof concrete must be buried accurately before concrete pouring, and it is forbidden to make holes after structural pouring.
(3) Key points of external wall waterproof monitoring
The key points of external wall waterproof monitoring are deformation joints, construction holes, wall-penetrating pipes and embedded parts waterproof construction.
1. Improper handling of external wall deformation joints can also easily lead to rainwater infiltration. When setting deformation joints, waterproof fortification should be considered simultaneously, and effective measures should be taken to ensure that rainwater will not penetrate through the joints. When waterproofing deformation joints of external walls, polymer waterproofing membrane and stainless steel plate can be used to establish a three-dimensional fortification system. Please refer to this article for specific fortification requirements. .
2. According to the construction scheme, even the wall pole of scaffolding needs to be fixed on the building, and there will inevitably be holes for the wall pole to pass through in the external wall masonry project. When repairing the hole of the connecting rod of the external wall, special attention should be paid to cleaning the mortar and sundries in the hole, sprinkling water to wet it, and repairing it with the same block as the original masonry.
3. Waterproof construction of embedded parts. The joint between the embedded parts in the wall and the waterproof layer of the external wall will cause cracks in the waterproof layer of the external wall and form a waterway. When it rains, it will enter the room along the cracks at the root of the embedded parts, causing leakage. Therefore, when installing embedded parts, the drawings should be verified first, and rust removal and anti-corrosion treatment should be carried out before installation. When plastering, the roots of embedded parts should be carefully operated and plastered.
(four) the kitchen, bathroom, bathroom waterproof monitoring points
Polymer cement waterproof coating is used in indoor bathrooms, kitchens and other rooms with waterproof requirements. Its construction technology includes: cleaning, wetting the base, drawing the baseline, treating the embedded pipeline, treating the U-shaped groove at the root of the floor drain, treating the additional layer of details, constructing the waterproof layer of caisson in the sunken bathroom, checking the waterproof layer of caisson, returning caisson to the sky, plastering with mortar, constructing the secondary waterproof coating on the ground and wall, and self-checking.
1. Prepare mortar with polymer emulsion, cement and sand according to the weight ratio of 1: 2: 4, fill the U-shaped groove into a convex shape, compact and polish it. When the pipeline is installed close to the ground, both sides of the pipeline should be wrapped, filled and polished with polymer waterproof mortar. With polymer cement coating, paste alkali-resistant glass fiber cloth to strengthen the pipe joint, water guide pipe and around the downcomer, and the coating thickness should not be less than 2mm.
2. Use polymer emulsion, cement and sand as mortar according to the weight ratio of 1: 2: 4, and make the internal corner into an arc of about 80 mm- 100 mm, and then use polymer cement waterproof coating to spread alkali-resistant glass fiber cloth for reinforcement after it is slightly dry and non-sticky.
3. The polymer emulsion and ordinary portland cement shall be configured according to the weight ratio of 1: 1. The waterproof layer shall be painted from inside to outside in the order of caisson facade, back bottom and crisscross, and it shall be painted for not less than three times, and painted for the second time every time, until the surface of the coating in the previous time is not sticky. Otherwise, the moisture at the bottom of the coating is sealed under the upper coating, which can't be evaporated in time, and it is easy to destroy the previous coating when it is painted again, leading to peeling and wrinkling, and destroying the integrity of the coating. The height of waterproof coating in bathroom shower should not be less than 1800mm, and the waterproof layer at the threshold should not be less than 300 mm.
4. When backfilling the sunken toilet, pay special attention not to damage the waterproof layer, do not damage and loosen the embedded pipeline, tamp the backfill layer, and wipe it with mortar for 30-50 mm after initial setting.