Measures to prevent common quality problems of residential construction projects
(A) the procurement and use of materials
When purchasing materials, finished products and semi-finished products, regular manufacturers should be selected with nationally recognized product certificates and certificates. Quality certificate and inspection report shall be attached when entering the site, and the original inspection report shall be provided for steel and cement. A second interview should be conducted when entering the site, and it can only be used if it is qualified. Moreover, the main road must be approved by the owner and the supervisor before purchase, and the certification procedures must be fulfilled.
(2) Quality and technical measures of subdivisional work
1. Due to the small area of this project, a reasonable survey control network is established, and the construction is carried out in strict accordance with the survey setting-out scheme and measures to ensure the accuracy of axis, elevation and detail size.
2, template before use, must carefully check the quality of board face, board face must besmear brushs isolation agent, qualified rear can use.
3. After the special-shaped beams and columns are made with wooden molds, the tiny sundries in the molds are sucked out with a vacuum cleaner.
4, when the beam, column template, template and metope contact set sealing strip, ensure that the vibrating concrete does not run, run, leak.
5, steel bar diameter, quantity, model, shape should comply with the design requirements, reinforced joint position should be accurate, floor reinforcement shall not be arbitrarily truncated.
6. Plain concrete with a thickness of 150mm shall be laid on the ground of the sand and gravel factory to ensure the cleanliness of sand and gravel aggregate.
7, concrete continuous pouring to vibrating compaction, after vibrating to cover the inner surface, and water conservation, protect the concrete in a wet state of not less than 7 days.
8, masonry engineering should be full of mortar, block horizontal flat vertical, adding Rachel reinforcement according to the design requirements, especially the joints between concrete members and masonry shall not be missed.
9, door and window frame should be strong, frame edge and brick, concrete contact place must be embedded soil brick or iron horse, and should have anti-corrosion and anti-rust measures.
10, metope, ground plaster, its base must be carefully cleaned, according to the provisions, besmear brushs mortar or mucilage before rendering, water conservation after the completion of the ground plaster not less than 7 days.
1 1, reasonably organize and arrange the plumbing and civil construction procedures to prevent the existing waterproof layer from being damaged by post-drilling.
(3) Prevention and control measures for common quality faults of each branch project
1, main works
(1) "Broken tendons", "rotten roots" and condensation around the seismic structural column
Principle: The residual mortar, slag and other sundries at the bottom of the column are not cleaned, and the concrete leaks, vibrates falsely or "slips". Improper handling of constructional column position and node.
Measures: the constructional column should be set in the wall, and the design department should draw the joint structure diagram according to the requirements of thermal insulation performance. The construction unit shall carry out the construction in strict accordance with the design requirements.
The joint between the constructional column and the wall is made into a horse-tooth shape, and two Ф 6 Rachel bars are set every 500mm along the wall height, and each side extends into the wall not less than1m.. Before pouring concrete, sundries should be thoroughly removed, and the brick wall along the formwork and Maya bifurcation should be fully watered and wetted from top to bottom. Concrete joints should be located at 100 mm on the ground, and cleaning openings should be set. When pouring concrete, it should be compacted by layers.
(2) The cast-in-place reinforced concrete overhangs and awnings produce irregular cracks perpendicular to the building wall.
Reason: Cast-in-place reinforced concrete overhangs and awnings are open-air components, which are not only affected by load, but also by temperature and concrete shrinkage, resulting in tensile stress greater than concrete tensile strength.
Measures: According to the requirements of the building facade, whether the load of each section of the long overhangs is uniform, the structural position, constraints and other factors, 10 mm joints shall be set every 4-6 meters during concrete construction, asphalt mortar shall be filled in the joints, and grooves shall be set when plastering the lower part. The upper part of the joint with waterproof requirements should be covered with waterproof material. When pouring concrete, the position of steel bars should be technically distributed, straight and not bent.
(3) The deviation of the bottom mark of cast-in-place reinforced concrete floor slab is large and the inclination is large.
Reasons: the elevation of the top surface of the cast-in-place reinforced concrete slab formwork is inaccurate, the formwork is not firm, the precast slab is not accurately leveled before installation, and the shelving end is uneven.
Measures: The bricklaying subdivisional work must be carried out in strict accordance with the elevation of the skin pole, and the vertical dimension of the masonry should be controlled. The elevation of the top surface of the wall should be taken as the key inspection item during the sub-item quality inspection; When the cast-in-place slab is dismantled, the elevation of the top surface should be strictly controlled, and the reinforcement engineering construction can only be carried out after the formwork is accepted.
(4) Prevention and treatment of honeycomb, holes and pits on the surface of cast-in-place concrete members
Cause: The operation was not carried out according to the specifications during construction, and the vibration was not compact.
Measures: Before the template is used, it should be carefully trimmed and coated with isolation agent. When the concrete is vibrated, it should be carefully and carefully, and no vibration can be missed. When the cement slurry returns, it should be vibrated again. Coagulation protective layer must be firmly padded with iron pad, and shall not leak, and shall not be knocked off during construction. To strengthen the water conservation of concrete, the water frequency should always keep the surface moist to ensure the specified maintenance days.
2, floor engineering
(1) The toilet floor is leaking.
Reasons: The waterproof layer on the ground of the room with water is not straight, the construction quality is not good, and the waterproof parts of the pipe root and column root are not fine. After entering the house, the waterproof layer and waterproof structure were repaired and the slope was broken.
Measures: When designing, ensure that the ground elevation of the room with water is 20mm lower than that of other rooms.
Waterproof layer should be laid on the ground elevation of rooms with waterproof requirements, such as toilets. The floor structure layer is cast-in-situ reinforced concrete or a whole precast reinforced concrete slab, and the surrounding supports should be provided with upturned beams, the height of which should not be less than 120mm and the width should not be less than 100mm.
Construction shall be carried out in strict accordance with French design requirements and specifications (GB50209-95). Structural layer elevation and reserved hole position should be accurate. Riser, casing, floor drain and floor slab shall be sealed according to the specification requirements before leveling layer is laid, and water stop rings shall be set for pipes crossing the floor slab to ensure that the slope proves to meet the design requirements. Waterproof materials for four pipes crossing the floor should be coated on the upper berth and exceed the upper opening of the casing. The upper berth should also be coated with waterproof material close to the ground and 200-300mm above the ground or the height required by the design. Waterproof materials should be added at the corner of Yin and Yang and at the root of the pipeline crossing the floor.
After the waterproof layer is laid, the water storage should be checked, and the water storage depth is 20-30mm. If there is no leakage within 24 hours, it is qualified and recorded.
The installation of bolts and pipe suspenders of sanitary ware should be closely coordinated with civil engineering, and embedded in construction to prevent the waterproof layer from being scratched, smashed and damaged after completion. Residents are not allowed to dig, smash or break the waterproof layer and waterproof structure when entering the house decoration.
(2) The cracking, sinking and filling of the first floor do not meet the requirements.
Reason: The backfill soil contains too much organic matter and sundries, and it is not compacted by layers as required.
Measures: Strictly control the soil material and optimum water content of backfill soil, and test its compaction coefficient in strict accordance with regulations. Only when the requirements are met can the upper soil be paved.
3, plastic doors and windows engineering
(1) The quality and installation quality of plastic doors and windows do not meet the requirements, and the surrounding area is seriously dewed.
Reason: The product quality did not meet the standard requirements, and the installation did not strictly implement the operating procedures.
Measures: plastic
Summary of preventive measures for common quality defects in residential building engineering: Reasons: the waterproof layer on the ground of the room with water is not straight, the construction quality is not good, and the waterproof parts of the pipe root and column root are not fine. After entering the house, the waterproof layer and waterproof structure were repaired and the slope was broken.
Materials doors and windows must adopt qualified products recommended by the management department. Installation shall be carried out by qualified units. Plastic expansion screws should be used for the outer frame and the hole, and they should not be fixed on the brick joints to ensure reliable elastic connection, and the outer frame should not be directly embedded in the wall.
When there is no requirement for the design of plastic doors and windows, the expansion and contraction between the frame and the hole should be filled with mineral wool strips and glass wool felt strips in layers, leaving 5-8 mm notches inside and outside, and sealed tightly with foaming sealant.
The gap between the frame and the hole should be filled with benzene board insulation material, and sealant joints should be set inside and outside. When plastering, the plastering layer should be separated from the door and window frame with a thickness of 5 mm, the plastering surface should exceed the door and window frame, the outer layer thickness should not be less than 10 mm, and the inner side should not affect the opening of the fan. After the plaster layer hardens, the plate should be taken out and sealed with sealant.
4, decoration engineering
(1) The wall is dewy and the paint is moldy.
Causes: some joints of concrete columns and beams do not meet the thermal requirements, the water in the wall is not fully released during construction, the wall is not completely dry, the heating in winter is not up to standard, improper management and improper use.
Measures: The joint treatment details of concrete columns and beams that do not meet the thermal requirements must be drawn in the design and construction drawing. The reserved holes of fire hydrants and distribution boxes arranged in stairwells should always be insulated with benzene board materials to ensure the requirements of low thermal resistance.
Carry out the construction in strict accordance with the specification requirements to ensure that the wall mortar is full. After the completion of the project, the wall should be ventilated and dried as soon as possible. Before the coating is put into use, it must be re-tested to confirm that the product quality meets the requirements. Heating should meet the standard requirements, and attention should be paid to ventilation when the indoor relative humidity is too high during use.
5, roofing engineering
(1) roof leakage
Reasons: the immersion height is not enough, local water is accumulated, the detailed treatment is not strictly in accordance with the specification requirements, and the construction is rough.
Measures: The roof waterproof project should be constructed by a professional waterproof team, and the detailed structure and related technical requirements in the construction drawing should be mastered through the blue prints.the design before construction. Before laying the gas barrier and waterproof layer, the base must be cleaned and kept dry, and the parapet height meets the requirements (greater than or equal to 250 mm). Roof slope must ensure the drainage slope and comply with the design requirements, so that drainage is given priority to and drainage prevention is combined.
Detailed structures such as drainage pipes, exhaust pipes and downpipes outside the roof must strictly implement the relevant provisions of Technical Specification for Roof Engineering (GB50207-94).
Check whether there is water leakage on the roof and whether the drainage system is unobstructed, which can be carried out after rain or continuous watering for 2 hours. The roof that can be tested for water storage should be tested for water storage.
After completion, the user shall designate a special person to be responsible for roof management. Managers should check and clean before the rainy season and winter every year, rectify problems in time when they find them, and make maintenance records.
(2) Dew condensation on the top ceiling
Causes: The roof insulation materials and products have high moisture content, false paving pressure, insufficient thickness, invalid gas barrier and improper use and maintenance.
Measures: The quality of roof insulation materials and products must meet the specification requirements, and a quality certificate must be attached when entering the site. Before construction, the density and water content of materials shall be sampled and rechecked. The moisture content of the insulation layer in the closed test should be equivalent to the equilibrium moisture content of the material in the local natural air-drying state (for example, the diffusion of perlite should not exceed 2%); When using organic cementing materials, it shall not exceed 5%, and when using inorganic cementing materials, it shall not exceed 20%.
Loose thermal insulation materials shall be laid in layers and properly compacted. Plate insulation materials should be laid and stabilized, and the gaps between plates should be filled with similar materials.
During the construction of insulation layer, the moisture content and laying thickness of insulation layer should be checked at fixed points, and the moisture content must be sampled and determined at the construction site. Finished product protection measures should be taken for thermal insulation houses under construction or after construction to prevent the moisture content from increasing due to wet rain.
At the joint between the roof and the wall (the protruding part of the roof), the gas barrier should be continuously laid upward along the wall, which is more than 150 mm higher than the upper surface of the insulation layer.
The above measures to prevent common quality defects in residential construction projects are collected and sorted by Zhong Da Consulting. For more architectural knowledge, such as Prevention Measures for Common Quality Problems in Residential Construction Projects, you can pay attention to the column of Zhong Da Consulting Industry. "It is easy to win the bid with a little construction." For information about construction enterprises, please visit Zhong Da Consulting, Building Link or follow the official account of Zhong Da Consulting WeChat for information.
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