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Preventive measures for common quality problems of school engineering leakage?
It is very important to take preventive measures against the common quality problem of school engineering leakage. Only by taking precautions can we do our best, and every detail should be handled in place, combined with the actual situation. Zhong Da Consulting will explain to you the preventive measures for the common quality problem of school engineering leakage.

The common problem of engineering quality leakage has brought great trouble to users and seriously affected their normal use. The common quality defects of the project mainly include roof, bathroom, basement, leakage of external doors and windows, pipe blockage, shell peeling on the decoration surface, etc. Once this project is won by our company, common faults will be taken as the focus of project quality control, and targeted preventive measures will be taken according to the characteristics of this project.

1 roof leakage prevention measures

Cause analysis of 1. 1;

The main causes of roof leakage are: the insulation layer and insulation layer are shelled, the quality of waterproof raw materials is unqualified, the slope is not enough, the coiled material is not laid and lapped enough, the edge is not firmly bonded, and the connecting parts such as pipes and ventilation shafts pass through the roof.

1.2 preventive measures

1. Before construction, the base should be kept dry until the cement mortar turns white. The surface shall be clean, flat and firm, free from peeling and sanding, and the waterproof layer shall be flat and uniform, free from peeling, cracks, blisters and other defects. Every brush should wait until it is completely dry before brushing the next one. Don't walk on the coated conjunctiva until it hardens. When pouring fine stone concrete on waterproof coating and waterproofing membrane, it should be strictly controlled, and pay attention to the fact that the waterproof layer will be damaged when the trolley falls.

2. When the pipes passing through the roof, such as ventilation pipes and downpipes, are filled with fine stone concrete for the second time, and neoprene is coated around the pipes for two times. After water filling test, if there is no leakage, cement mortar powder will be used again, and then the pipe will be made into a small steamed bun with a height of 3㎝ to ensure that the pipe will not leak through the board surface.

3. Besides the pipes passing through the roof, smoke crossings, ventilated places and other parts are also prone to water leakage. The method to prevent the joint from leaking is to plant steel bars in front of the pipeline well, then pour 30㎝ high concrete as the guide wall, and then build on the guide wall. In order to avoid brush leakage of brick masonry, the method of brushing while laying bricks is adopted.

4. The joint between the roof base and the protruding roof structure, and the corner of the base (impinges mouth, gutter, roof, etc. ) make R250 arc, change the flashing position of parapet to concave flashing, and seal the closed position with sealing material. The upper opening of the coil head is covered with a metal buckle plate and sealed with sealing ointment.

5, rigid waterproof layer and gable, parapet junction should leave a 30㎜ wide gap, and embedded with sealing material, laying coil and additional layer in the flashing place.

6. When the construction project with a gutter is completed and accepted, the roof will be subjected to a 24-hour water storage test overnight (the outlet is temporarily blocked), and the gutter will be filled with water during the test.

2 toilet leakage prevention measures

1, concrete guide wall with a height of 20㎝ and a width of 120㎝ is poured around the wall root. Before pouring concrete, cut the original ground and clean it up. Before concrete pouring, connect the cement slurry with plain cement slurry.

2. After the installation of toilet water pipes, assign personnel to be responsible for the secondary grouting through the reserved holes in the floor. The caulking material is C20 fine stone concrete. After sealing, chloroprene rubber waterproof coating is applied around the pipeline. Water filling test for 24 hours, and then pour the floor after it is confirmed that there is no leakage. After the floor is poured, make it into the shape of steamed bread next to the pipeline.

3. According to our company's experience, the toilet should be 2㎝ lower than the floor in structural construction.

3 pipeline sanitary ware joint leakage and pipeline blockage prevention measures

1, the main reason for the leakage of pipeline sanitary fittings is that the raw materials of pipeline sanitary fittings are inferior and the installation is not sealed.

Precautionary measures: Before the pipeline is used, the quality of the pipeline should be checked by irrigation method, and the interface between the pipe joint and sanitary ware should be tested by one-time disassembly method. After the trial connection is qualified, the auxiliary materials such as raw material adhesive tape, white lacquer linen yarn or special glue for pipe joints can be formally connected. Before the pipeline sanitary ware is submitted, all tests such as pressure test, ball passing and water filling must be carried out to avoid false sampling inspection on completion acceptance.

2. The main reason for pipeline blockage is that there are no effective measures to prevent things from entering the pipeline when installing risers and sewage pipes without sanitary ware equipment.

Precautionary measures: When installing wastewater drainage risers and drains, temporary nozzle plugs or covers (metal iron covers or wooden plugs can be used) should be added to each nozzle at any time according to the requirements of construction progress.

4. Leakage prevention of external doors and windows

The installation of aluminum alloy doors and windows must be carried out in strict accordance with the specified construction acceptance specifications. Controlling the quality of key processes and improving the installation quality of doors and windows are effective measures to eliminate the common faults of installation quality and prevent leakage around windows.

1, do well the blue prints.the design, improve the details of nodes, and ensure the design quality. Doors and windows should be selected according to the engineering characteristics and local climate conditions, and the series models should be selected through the calculation of wind pressure intensity, and the detailed drawings of vertical and horizontal bar connection nodes should be provided, and the performance index requirements should be put forward. Doors and windows should be tested for water tightness, air tightness and wind pressure strength, and can only be used in engineering after reaching the performance index proposed by the design, so as to prevent small cross-section and low-grade profiles from being used in engineering. In the installation process, we should adhere to the three inspection system, and the supervision unit should strictly check the key parts, do a good job in hidden acceptance, and eliminate the common quality problems in the installation process during the construction process.

2. Strictly control the reserved size of the hole and arrange the construction sequence reasonably. In the construction of the main structure, size of the hole and reserved doors and windows should be strictly controlled. There should be no deviation in the reserved size of holes, or too many holes are reserved without considering the internal and external decorative surfaces, which makes it difficult to install connectors and fill gaps; The reserved hole is too small to be embedded, and the position deviation is too large, which leads to different gap sizes at both ends and affects the installation quality of doors and windows. The installation of doors and windows should be carried out after the wall surface is hardened on the wet operation completion day, that is, the inside and outside should be scraped first, and then the line should be installed. This will not only make the gap between the frame and the wall even and straight up and down, but also be beneficial to the protection of finished products.

3. Fixation of doors and windows. In the way of fixing the connector to the wall, the wall material should be considered. It is forbidden to fix it on the brick wall with nails or steel nails, nor to fix it on the perforated brick with expansion bolts.

The number and position of connectors should be set at the corner of the frame not more than 180mm, and the spacing between the points thereafter should not be more than 500mm, so as to ensure the reliable connection between the frame and the wall.

4. The choice of embedded wall materials. Reasonable selection of filling materials is not only convenient to operate, but also can make the filling compact and ensure the sealing quality. Here, it means that cement mortar must not be selected as the material for filling the gap, but soft materials such as frame cotton sliver, glass wool felt strip and polyurethane PU foaming agent must be selected for filling, and the filling should be layered to be full and dense.

5. Inject the sealing material accurately. Sealing the gaps around the window frame with sealant is the first line of defense to prevent leakage. According to the specification requirements, a notch with a depth of 5-8mm should be left on the surface of the gap and filled with sealing material. When the decorative surface is constructed, the battens shall be embedded, and the battens shall be 5 mm× 7 mm After the decorative surface is completed, the battens shall be taken out, and the notches shall be continuous. The sealant should be injected into the notch from bottom to top. When plastering the window sill, 3-5mm should be extended into the lower window sill, and glue should be injected at the internal corner to ensure the thickness and width of glue injection and avoid pollution. Clean the surface before injecting glue, and check the surface after injecting glue.

5 basement exterior wall seepage control

The basement of this project adopts waterproof concrete, which is widely used. However, if we are not careful in actual construction, it will lead to leakage of external wall panels. According to the previous construction experience, our company summed up the following points to ensure the quality of concrete.

5. 1 Material aspect

1, choose cement with low hydration heat, such as slag cement.

2. Adding admixture, HEA efficient concrete waterproofing agent with cement content of 8% can not only reduce cement content and hydration heat temperature, but also compensate shrinkage and produce tensile stress. Under the constraint of steel bars and adjacent positions, the preloading stress of 0.2-0.7Mpa is established in concrete, which can completely or partially offset the tensile stress caused by dry shrinkage and cold shrinkage in the middle and late stage of the structure, thus preventing or reducing the occurrence of shrinkage cracks.

3. Optimize the gradation of sand and gravel, control the silt content and sand ratio, and make the concrete mortar full, thus increasing its compactness.

4, control the concrete into the mold temperature, try to reduce the cold shrinkage caused by the temperature difference between inside and outside the concrete.

5. Optimize the mix proportion to ensure the later strength of concrete and reduce the cold shrinkage cracks caused by high early strength of concrete.

5.2 Construction aspect

1, before the waterproof concrete is cast, the sundries falling in the formwork shall be removed, and the steel bars and wires set inside the structure shall not touch the formwork. If wooden formwork is used, it should be watered and wetted in advance.

2. Concrete pouring: When pouring the concrete wall, the bottom surface should be cleaned, and a layer of cement mortar with a thickness of 2-3CM should be laid first (that is, stones should be removed by using the original concrete mixture ratio) or stone-reduced concrete with the same mixture ratio. The concrete height in the first step is 50㎝, and then the concrete height in each step is 100㎝, which shall be poured in the order specified in the construction plan. In order to ensure that concrete does not segregate when pouring, concrete falls freely from a height, and the falling distance shall not exceed 2m. When the height is more than 3m, string drums or chutes can be used according to the site conditions.

3. Vibrating of concrete: The concrete is vibrated mechanically to ensure its compactness.

Plug-in vibration, fast plug-in and slow pull-out, until there is no bubble on the surface.

The spacing between insertion points should not be greater than 50㎝ to prevent vibration. The parts with small structural section and dense steel bars shall be operated in strict accordance with the principle of layered pouring and layered vibrating. Vibrating and plastering should start from symmetrical positions to prevent the formwork from moving. When pouring to the surface, the concrete must be vibrated again before the vibrating limit (that is, the design that the concrete can recover its plastic state after vibrating). At this time, the vibrator is inserted into the concrete by its own gravity to vibrate, and the concrete can still close itself after carefully pulling out the vibrator, thus eliminating the moisture and cracks generated by concrete bleeding in the lower part of coarse aggregate and horizontal steel bars, and improving the bonding force between concrete and steel bars.

4. Maintenance. At room temperature, concrete must be watered and cured within 4-6h after pouring, 4-6 times a day within 3d, and 2-3 times a day after 3d, and the curing time shall not be less than 14d. In order to pry loose the rear side touch in 3d, it is advisable to water the gap between the side touch and the concrete surface to keep it moist.

5.3 Node Processing

Some special measures should be taken for the parts that are easy to leak, such as through-wall bolts, through-wall pipes, construction joints and post-pouring belts.

1, construction joint

In general, construction joints should be left as little as possible. The horizontal joint between the wall and the bottom plate should be 250MM away from the bottom plate and not less than 300mm away from the hole in the wall, and it should be avoided to stay in the place where the bending distance or shear force is the largest on the wallboard. Self-expanding rubber sealing joint is the best construction joint for basement exterior wall.

2, through-wall bolts

(1) The method of stopping water and supporting the head can be adopted. After form removal, remove the stow-wood at the support head of water stop on both sides, and then block it with expansive cement mortar.

(2) The embedded casing can be used, and the sealing ring can be welded on the casing at the same time. After the formwork is removed, this part is sealed and compacted with expansive cement mortar.

3. Post-pouring belt: The post-pouring belt of this project adopts flexible splicing treatment, that is, rubber water stop. Before pouring the post-cast strip, the concrete surface on both sides of the joint should be roughened, cleaned and wetted before pouring. Micro-expansive concrete should be used in post-cast strip. The temperature of post-cast strip is as close as possible to the temperature of main concrete.

4. Through-wall pipeline

When the pipeline crosses the basement exterior wall, the casing should be embedded, and the single water supply pipeline and single water supply and drainage pipeline should be constructed according to the design drawings or adopted according to the relevant instructions in the water supply and drainage standard drawings.

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