Construction method for preventing cracking and leakage of residential buildings

Abstract

The application discloses a kind of residential building anti-cracking anti-leakage construction methods, can guarantee main structure anti-cracking anti-leakage while preventing pipe floor node, bathroom caisson, wall plaster, chimney periphery and other detail nodes, masonry wall and secondary structure cracking, leakage, improve the overall anti-cracking anti-leakage effect of residential building;The method comprises floor anti-cracking construction, wall anti-cracking construction, basement anti-cracking and anti-leakage construction, chimney anti-leakage construction, bathroom caisson anti-cracking and anti-leakage construction, indoor wall root anti-leakage construction, outer wall, roof and pipe opening anti-leakage construction, and bathroom caisson drain pipe anti-leakage construction.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a construction method for preventing cracking and leakage in residential buildings. Background Technology

[0002] Crack and leakage prevention construction in building construction is a crucial control measure that directly affects the quality of building construction, its service life, and residents' living experience. Currently, crack and leakage prevention construction in building construction typically focuses on preventing cracks and leaks during the construction phase of the main structure (such as exterior walls and basements). For example, using impermeable concrete for the exterior walls of the main structure and installing post-pouring strips and external waterproofing layers on the basement floor slab and side walls are methods that can effectively control cracking and leakage in large areas of the main structure.

[0003] However, the aforementioned construction methods primarily focus on preventing cracking and leakage during the large-scale construction phases of the main structure's exterior walls and basement, neglecting intermediate floor slabs, detailed joints, and secondary structural components. For example, cracking and leakage prevention in building structures such as floor slabs, pipe penetration points, bathroom recesses, wall plastering, flue perimeters, and masonry walls are easily overlooked. These areas are typically high-risk for cracking and leakage, resulting in high maintenance costs and a poor living experience when leaks occur during the building's usability phase. Specifically, floor slabs often crack due to premature removal of formwork supports, flues are prone to leakage during the finishing stage, wall plastering is prone to hollowing and cracking, and masonry walls are prone to cracking at junctions. Among these areas, cracking problems are particularly prominent at pipe penetration points and bathroom recess construction. In existing technologies, the crack prevention measures for pipe penetration joints in floor slabs, such as pump pipe penetration joints, usually involve using wooden beams to compact the space between the pump pipe and the pump pipe hole. However, the concrete pouring for the pump pipe generates vibrations, which are directly transmitted to the floor slab through the wooden beams, easily causing cracks at the pump pipe hole. For drainage pipe penetration joints in floor slabs, after the drainage pipe passes through the pipe opening in the floor slab and the bottom formwork of the opening is installed, the existing method of fixing the bottom formwork usually involves setting iron wires on the bottom formwork and hoisting the bottom formwork through the floor slab with the upward iron wires. After construction, the iron wires are permanently embedded in the floor slab. Due to the difference in shrinkage rates between the iron wires and concrete, and the fact that the iron wires themselves are prone to corrosion, leakage channels are easily formed at the iron wires, leading to water leakage at the point where the drainage pipe penetrates the floor slab.

[0004] The construction of the bathroom sump is usually carried out together with the main structure floor slab. The side formwork of the bathroom sump is usually fixed by passing iron wire through the bottom plate of the sump and setting wooden strips on the side formwork to keep the side formwork at a preset height. This fixing method is also prone to leakage channels at the iron wire and is also prone to water leakage of the sump back slope.

[0005] In summary, in building construction, ensuring the main structure is free from cracks and leaks while preventing cracks and leaks in detailed joints and secondary structural parts is a key issue. Summary of the Invention

[0006] One of the objectives of this invention is, at least, to provide a construction method for preventing cracking and leakage in residential buildings, addressing the problems existing in the prior art. This method can prevent cracking and leakage in secondary structures such as pipe penetration joints, bathroom recesses, wall plastering, flue perimeters, and masonry walls while ensuring the main structure is crack-proof and leak-proof, thereby improving the overall crack-proof and leak-proof effect of residential buildings.

[0007] To achieve the above objectives, the technical solution adopted by the present invention includes the following aspects.

[0008] A construction method for preventing cracking and leakage in residential buildings, comprising: Floor slab crack prevention construction The water-cement ratio of the floor slab concrete should not exceed 0.5, the maximum amount of fly ash or mineral powder should be 25% of the cement content, and the on-site slump of the floor slab concrete should not exceed 180mm; during floor slab construction, at least two layers of formwork support should be maintained; when pump pipes penetrate pump pipe holes in floor slabs that are less than 28 days old, a flexible material with a thickness of not less than 50mm should be wrapped around the pump pipe, with the flexible material located between the pump pipe and the pump pipe hole. Wall crack prevention construction This includes crack prevention construction for wall plastering, crack prevention construction for walls at the junction of different materials, crack prevention construction for wall surface conduit locations, and crack prevention construction for masonry mortar joints; Basement crack prevention and leakage prevention construction This includes preventing cracking of the post-cast strip in the basement roof slab, preventing vertical cracking of the basement exterior shear walls, and preventing overall leakage in the basement. Flue leak prevention construction This includes roof flue waterproofing construction and floor flue waterproofing construction; roof flue waterproofing construction includes: when constructing the roof, pouring roof flue sills in the flue construction area on the roof. The roof flue sills are poured together with the roof concrete, and the height of the roof flue sills is not less than 300mm. The construction of the flue waterproofing on each floor includes: before plastering the kitchen wall, setting an indoor flue curb at the base of the indoor flue. The construction of the indoor flue curb is carried out together with the sealing of the openings around the flue. The indoor flue curb has a cross-section of 150mm high and 80mm wide and is constructed with C20 plain concrete. Construction of bathroom recessed sump to prevent cracking and leakage Thicken the bottom plate of the caisson by 10-20mm, and vibrate the beams around the bottom plate of the caisson twice until they are compacted. When constructing the upper caisson, support the formwork of the upper caisson on the beams on both sides of the lower caisson. During the installation of the caisson side formwork, set horizontal iron at the four corners of the bottom of the caisson side formwork, and weld the horizontal iron to the stirrups of the beam outside the space enclosed by the caisson side formwork. Fix the opposite caisson side formwork with wooden beams in a longitudinal and transverse symmetrical manner, and set triangular plates between adjacent caisson side formwork at the four corners for reinforcement. Waterproofing construction at the base of interior walls After constructing a 200mm high retaining wall at the base of the wall, proceed with the subsequent wall construction on the retaining wall. Exterior wall waterproofing construction This includes waterproofing construction for bolt holes in exterior walls, waterproofing construction for expansion joints in exterior walls, and waterproofing construction for brickwork in exterior walls. Roof waterproofing construction This includes waterproofing construction of roof panels and waterproofing construction of roof expansion joints. Pipe opening leak prevention construction During the construction of the floor slab, pipe openings are reserved in the area where drainage pipes pass through the floor slab. After roughening the pipe openings, two or more waterproof rubber rings are fitted on each drainage pipe. Then, the pipes are passed through the pipe openings and the waterproof rubber rings are positioned in the direction of the pipe opening height. A bottom formwork is set at the bottom of the pipe opening, and steel reinforcement supports are set at the bottom of the bottom formwork. One end of the steel reinforcement supports the bottom formwork, and the other end of the steel reinforcement supports the flange ring of the drainage pipe. Multiple steel reinforcement supports are arranged circumferentially along the flange ring. Construction of Leak-proof Drainage Pipes for Bathroom Recessed Areas After the drain pipes at the pre-set locations in the bathroom sump are installed and the pipe openings are sealed, the sump is waterproofed. After a water test confirms no leakage, a 100mm high curb is built around the drain pipes using solid bricks. Then, C20 plain concrete is used to construct a waterproof curb to the pre-set height. When arranging the drain pipes in the sump, the side drains are installed on the drain risers, and the secondary drains are installed at the lowest point of the sump.

[0009] Preferably, in the construction of the floor slab anti-cracking, when the floor slab thickness is not greater than 120mm and the floor slab reinforcement is a single layer of reinforcement, in the area where the conduit is laid, a 4mm@200*200 steel mesh or 6mm steel bars are laid under the conduit. When laying the reinforcement, the spacing between adjacent reinforcement bars is 300~350mm, and the two ends of the steel mesh or steel bars in the width direction extend 300mm from both sides of the conduit. Before pouring the floor slab concrete, place F-type or H-type precast concrete blocks in areas of the floor slab construction area that do not require waterproofing to control the thickness of the floor slab. The strength and thickness of the precast concrete blocks are the same as the strength and thickness of the floor slab. Place no less than 5 precast concrete blocks on each floor slab and no less than one precast concrete block in the center of the floor slab. During the concrete pouring process, ensure that the concrete is vibrated and compacted. After pouring, within 1 / 2 to 2 / 3 of the initial setting time of the concrete, mechanically grind the surface of the slab to finish the grout. When the concrete strength reaches 1.2 MPa or above, walk on the slab surface and install formwork and formwork supports.

[0010] Preferably, the wall plastering anti-cracking construction includes: wetting the ceiling and wall with water, then roughening the surface, curing with water for two days after roughening, and then plastering. The cement slurry for roughening has a mix ratio and viscosity that meet the requirements of being able to roughen without dripping. The spacing between two adjacent roughened sections is no more than 50mm. The roughening mortar is used up within 2 hours. When plastering the wall, the plastering mortar is used up within 2 to 3 hours. Construction to prevent cracking at the junction of different materials includes: roughening the surface at the junction of different materials and then hanging wire mesh, so that the roughness lifts the wire mesh, and then plastering is done after the wire mesh is separated from the masonry wall by a certain distance, so that the wire mesh is in the middle of the plaster mortar layer; for the top floor of the building, the wire mesh is fully hung on the inside of the exterior wall of the top floor before plastering. The construction process for preventing cracking of conduit locations on walls includes: installing conduits on the wall using pre-reserved, pre-embedded, or mechanically grooved or drilled methods; when opening grooves in masonry walls, ensuring the groove dimensions meet the following requirements: groove depth ≤ dn + 10mm, groove width ≤ dn + 60mm, where dn represents the conduit diameter; after the conduit is installed, filling the grooves tightly with cement mortar.

[0011] Preferably, the masonry mortar joint crack prevention construction includes: segmented masonry wall construction, with the daily construction height of the masonry wall not exceeding 1800mm; sloping top bricks are laid after a 7-day interval between masonry wall constructions, and prefabricated triangular blocks with an angle of 45-60 degrees are set at both ends of the top of the masonry wall when laying the sloping top bricks; secondary grouting is performed on the outer wall and sloping top brick sections until they are dense, and grouting is done casually during the construction of other walls, with the grouting treated before the mortar initially sets; when the sloping top bricks are laid to 20-30mm below the bottom of the beam, the gap between the top of the sloping top bricks and the bottom of the beam is filled with micro-expansion cement.

[0012] Preferably, the wall anti-cracking construction also includes the construction of anti-V-shaped cracks at the window sill corner: during the wall construction, a concrete coping is constructed at the top of the window sill, the concrete coping is reinforced, and both ends of the concrete coping extend into the wall from the top of the window sill by not less than 100mm. The wall crack prevention construction also includes crack prevention construction at the construction opening location: a precast concrete lintel is set at the top of the construction opening; when the toothed joints are not made on both sides of the construction opening, tie bars with hooks are embedded every 500mm along the height direction of the construction opening on both sides of the construction opening, with the tie bars extending 500mm out of the construction opening and 300mm embedded in the masonry wall; when plastering the masonry wall on both sides of the construction opening, a 150mm area around the construction opening is left unplastered; after the construction opening is built, a wire mesh is set at the construction opening, and the wire mesh extends to the reserved area around the construction opening and overlaps with the wire mesh on the masonry wall around the construction opening before plastering the construction opening.

[0013] Preferably, during the construction of the anti-cracking method for the post-pouring strip of the basement roof slab, a separate support system is set up at the post-pouring strip of the basement roof slab, and the formwork is separated from the basement roof slab support system. The formwork is removed after the post-pouring strip is poured and the strength reaches the design requirements. The basement external shear wall is a shear wall located around the perimeter of the basement near the excavation pit. During construction, the basement external shear wall and the retaining wall use the same grade of concrete. When different grades of concrete are used, the retaining wall and the basement external shear wall are spaced at least 100m apart, and the retaining wall and the basement external shear wall are separately formworked and poured separately. When the basement external shear wall is connected to the retaining wall, the curing of the concrete of the basement external shear wall is strengthened to ensure that the curing time is not less than 72 hours. At the part where the retaining wall and the basement external shear wall are connected, the tie rods are loosened first but the formwork is not removed. A perforated water pipe is placed on the top of the retaining wall for continuous watering, so that the water enters the gap between the formwork and the concrete along the joint of the formwork to keep the concrete surface moist and cured.

[0014] Preferably, the construction of the anti-seepage construction of the bolt holes on the exterior wall includes: when installing bolts for fixing the exterior wall formwork, the inner end of the bolt is 10-20mm higher than the outer end of the bolt; after the exterior wall formwork and bolts are removed, the bolt holes are sealed with waterproof mortar containing micro-expansion agent, and the waterproof mortar is compacted and smoothed with round steel. After the waterproof mortar dries, a polyurethane waterproof coating is applied to the bolt holes on the outer side, with two coats. The coating shape is a circle centered on the bolt hole. The diameter of the first coat is 10cm, the diameter of the second coat is 6cm, and the overall coating thickness is 1.5mm. The construction of the waterproofing of the external wall partition joint includes: reserving the external wall partition joint at the location of the external wall concrete beam, applying waterproof material to the plaster surface 100mm above and below the external wall partition joint, and densely filling the partition joint with grout; when the external wall partition joint uses a prefabricated plastic partition strip, after the plastering is completed, the prefabricated plastic partition strip is removed, and after applying two layers of waterproofing to the joint, it is filled with weather-resistant sealant. The construction of the exterior wall brick waterproofing includes: the exterior wall facing bricks are pasted with a special adhesive. During the pasting process, a thin mortar and full mortar construction technique is used, and the joints are grouted twice during the pasting process to avoid cavities, sand holes and gaps.

[0015] Preferably, the roof panel waterproofing construction includes: after the roof structure construction is completed, a water tightness test is conducted for 24 hours to ensure that the roof structure does not leak; then, a waterproof layer is constructed on the roof; after another water tightness test for 24 hours, a leveling layer is constructed on top of the waterproof layer; the leveling layer is divided into sections by cutting or leaving 3000*3000mm squares, with a joint width of 10~15mm; expansion joints are left or cut at 200mm around the perimeter of the structure, with the expansion joints having the same width as the section joints; during the construction of the section joints, section joints are set at the external corners of the roof structure, aligned with or perpendicular to them; Before the leveling layer is constructed, a continuous drainage ditch is set up around the perimeter of the roof, avoiding the side drains in an arc shape. The water in the ditch is connected to the rainwater downpipe on the exterior wall through a PVC drainage pipe that extends 100mm into the rainwater downpipe. Pebbles with a particle size of 5-8mm are laid in the ditch and wrapped with non-woven fabric. After the ditch is installed, two layers of non-woven fabric are placed on top of it.

[0016] Preferably, the construction of the roof expansion joint waterproofing includes: when constructing the top floor slab, simultaneously constructing concrete reverse edges on both sides of the roof expansion joint, and integrally constructing a horizontal edge on the top of the first side concrete reverse edge, with the horizontal edge extending horizontally to form a second side concrete reverse edge, and the bottom of the horizontal edge and the top of the second side concrete reverse edge being a certain distance apart, with weather-resistant sealant used to fill the gap.

[0017] Preferably, during the construction of the anti-seepage construction of the pipe opening, when pouring the concrete for the pipe opening, fine stone concrete mixed with 3% micro-expansion agent is used and poured in two stages to reduce shrinkage.

[0018] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects: While carrying out anti-cracking and anti-leakage construction on the main structure of the building, anti-cracking and anti-leakage construction was also carried out on details such as pipe penetrations through floor slabs, bathroom recesses, wall plastering, and the area around flues, as well as secondary structures such as masonry walls. This improved the overall waterproofing effect of the building, reduced maintenance costs during later use, and enhanced the living experience.

[0019] By improving the construction methods in areas such as bathroom recesses and pipe penetration points, the anti-leakage effect in these areas has been further enhanced. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the floor slab formwork support arrangement according to an exemplary embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the steel mesh arrangement at the location of the overhead conduit on the floor slab in an exemplary embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the steel reinforcement arrangement at the location of the overhead conduit on the floor slab in an exemplary embodiment of the present invention.

[0023] Figure 4 This is an elevation view of the arrangement of H-shaped precast concrete blocks in a floor slab, an exemplary embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the construction opening of an exemplary embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of the arrangement of the waterstop steel plate in the post-cast strip of the basement according to an exemplary embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of the arrangement of water-stop steel plates for horizontal construction joints in the basement sidewall, an exemplary embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram of the reverse curb arrangement at the kitchen flue in an exemplary embodiment of the present invention.

[0028] Figure 9 This is a schematic diagram of the arrangement of horizontal irons at the bottom of the caisson side mold in an exemplary embodiment of the present invention.

[0029] Figure 10 This is a schematic diagram of the longitudinal and transverse bracing arrangement of the caisson side mold according to an exemplary embodiment of the present invention.

[0030] Figure 11 This is a perspective view of the arrangement of longitudinal and transverse braces and triangular plates of the caisson side mold according to an exemplary embodiment of the present invention.

[0031] Figure 12 This is a schematic diagram of waterproofing the bolt holes on the exterior wall, which is an exemplary embodiment of the present invention.

[0032] Figure 13 This is a schematic diagram of the arrangement of the partition joints at the roof pergola column in an exemplary embodiment of the present invention.

[0033] Figure 14 This is a schematic diagram of a roof expansion joint structure according to an exemplary embodiment of the present invention.

[0034] Figure 15 This is a schematic diagram of the bottom formwork support structure for the pipe opening in a floor slab according to an exemplary embodiment of the present invention.

[0035] Figure 16 This is a schematic diagram of the inverted retaining wall arrangement at the outlet of the caisson drainage pipe in an exemplary embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so that the objectives, technical solutions, and advantages of the present invention will be clearer. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0037] An exemplary embodiment of the present invention provides a construction method for preventing cracking and leakage in residential buildings, comprising: Floor slab crack prevention construction Prepare floor slab concrete to prevent shrinkage cracks; when preparing floor slab concrete, ensure the water-cement ratio is no greater than 0.5, and the maximum amount of fly ash or mineral powder is 25% of the cement content; when the concrete is used for basement floor slab construction, add crack-resistant fibers (0.9 kg / m³) to the floor slab concrete; when the building height is no greater than 100m, ensure the on-site slump of the floor slab concrete is no greater than 180mm.

[0038] Prepare no fewer than three sets of floor slab formwork, and maintain formwork support for no fewer than two floors during floor slab construction (reference). Figure 1 This is to meet the formwork turnover requirement of 5 days per floor slab construction, and to avoid removing the formwork support of the floor slab when the concrete age (28 days) of the floor slab is insufficient and then using it for the construction of the floor slab above the floor slab, so as to prevent the floor slab from cracking due to insufficient support.

[0039] During floor slab reinforcement construction, when the floor slab thickness is no more than 120mm and the floor slab reinforcement is a single layer, a 4mm diameter 200*200mm steel mesh or 6mm diameter steel bars should be laid under the conduit in the conduit area. When arranging the reinforcement, the spacing between adjacent bars should be 300-350mm. Both ends of the steel mesh or bars should extend 300mm beyond the conduit on both sides to enhance the anti-cracking effect at the conduit location. This prevents the floor slab from thinning due to reduced effective thickness or vibrations during concrete pouring, which could cause the conduit to drag back and forth, creating gaps and leading to cracks at the conduit location. It also prevents the concrete below the conduit from settling naturally and the concrete above the conduit from failing to effectively fill the gaps, thus preventing cracks at the conduit location. (See attached diagram for a schematic of steel mesh installation under the conduit.) Figure 2 A schematic diagram of reinforcing bars installed below the conduit is provided for reference. Figure 3 .

[0040] After the floor slab reinforcement is installed and before the concrete is poured, F-type or H-type precast concrete blocks are placed in areas of the floor slab construction area where waterproofing is not required. These blocks are used to control the thickness of the floor slab. The strength and thickness of the precast concrete blocks are the same as those of the floor slab. At least five precast concrete blocks are placed on each floor slab, with at least one block placed in the center of the floor slab. The arrangement of H-type precast concrete blocks is as follows: Figure 4When pouring concrete for the floor slab, the actual thickness of the floor slab is calculated by combining the elevation of the lines drawn on the side formwork and the thickness of the poured concrete. If the actual thickness of the floor slab exceeds the standard, the poured floor slab is removed or repaired with floor slab concrete. During the floor slab pouring process, steel bars can also be used to randomly check the thickness of the floor slab to ensure that the thickness of the floor slab meets the requirements and to avoid cracking of the floor slab.

[0041] During the pouring of floor slab concrete, ensure thorough compaction through vibration. After pouring, within 1 / 2 to 2 / 3 of the initial setting time of the floor slab concrete, mechanically grind the surface a second time to enhance the compactness of the concrete, reduce concrete deformation and shrinkage, prevent settlement cracks, drying shrinkage cracks, and "loosening" of the top, and repair irregular cracks on the floor slab surface. After the initial setting of the floor slab concrete and before the final setting, regularly water it for curing, and cover the floor slab surface with a felt or burlap sack to prevent the surface moisture from evaporating too quickly and causing surface cracking. For the first two days of curing, cure at least 6 times a day to maintain the surface humidity of the concrete. When the concrete strength reaches 1.2 MPa or above (judged by whether a person leaves a footprint on the floor slab surface), walking on the floor slab surface and installing formwork and formwork supports are permitted. This is to prevent the floor slab from being damaged due to insufficient concrete strength and inability to bear the load generated by walking or stacking materials on the floor slab too early.

[0042] During floor slab construction, rectangular pump pipe holes are usually reserved to allow the pump pipe to pass vertically through the holes for concrete pouring of the upper floor slab. When the pump pipe passes through the pump pipe hole of a floor slab less than 28 days old, a flexible material (such as safety net, tire, burlap sack, etc.) with a thickness of not less than 50mm is wrapped around the pump pipe. The flexible material is placed between the pump pipe and the pump pipe hole to reduce the vibration of the pump pipe to the floor slab during concrete transportation, thereby reducing the risk of floor slab cracking. Compared with directly using wooden beams to compact the pump pipe and pump pipe hole, wrapping the pump pipe with flexible material can prevent the vibration generated by the pump pipe during concrete transportation from being directly transmitted to the floor slab through the wooden beams, further preventing floor slab cracking.

[0043] Wall crack prevention construction Wall crack prevention construction mainly includes wall plastering crack prevention construction, wall surface crack prevention construction at the junction of different materials, and wall surface conduit location crack prevention construction. Among them, wall plastering crack prevention construction includes: before plastering, wetting the ceiling and wall with water, then roughening the surface, and after roughening, wetting and curing for two days; the cement slurry (cement, sand, water and 801 glue) for roughening is mixed and the viscosity is such that it can roughen without dripping, the spacing between two adjacent roughened sections is no more than 50mm, and the roughened mortar is used up within 2 hours; by temporarily wetting and curing before and after roughening, and by controlling the roughening spacing and quality, it is possible to avoid incomplete roughening, improve the roughening strength, thereby improving the adhesion between the wall plaster layer and the base layer, and avoiding hollowing and cracking. When plastering walls, the plastering mortar should be used up within 2-3 hours. It is forbidden to use mortar additives (such as mortar king, mortar concentrate, etc.) in the plastering mortar, so as to prevent the amount of mortar additives from being difficult to control, which may lead to mortar dispersion, reduced strength, and increased risk of hollowing and cracking of the wall plaster.

[0044] Construction for preventing cracking at the junction of different materials involves: at the junction of masonry walls and cast-in-place walls, or at the junction of masonry walls and cast-in-place columns, first applying mortar (roughening), then hanging wire mesh. The roughening from the mortar lifts the wire mesh, creating a certain distance between the wire mesh and the masonry wall. This places the wire mesh in the middle of the mortar layer, relative to the bottom of the mortar layer where it adheres to the masonry wall. This placement in the middle of the mortar layer allows the wire mesh to fully exert its crack-resistant properties, enhancing the crack prevention effect at the junction of different materials. Because the top floor slab is more affected by thermal expansion and contraction than other floors, and the exterior walls are also affected by temperature differences, the inner side of the top floor exterior wall is more prone to cracking than the inner walls and other floors. Therefore, a full layer of wire mesh is hung on the inner side of the top floor exterior wall to further enhance the crack prevention effect; the diameter of the wire mesh is 0.6mm, and the mesh size is 15*15mm.

[0045] The construction process for preventing cracking of conduit locations on walls includes: when installing conduits in the wall, using pre-reserved, pre-embedded, or mechanically grooved / opened methods to avoid manual chiseling of the grooves; after the conduits are installed in the grooves, they should be filled and compacted with cement mortar; for hollow brick masonry walls, the conduits should be embedded in the holes in the hollow brick masonry wall during the wall construction process, and then filled with cement mortar or fine stone concrete after the conduit installation is completed; when pre-embedding conduits, use special conduit fixing hooks to fix them, avoiding the use of iron fixing rods; when hanging wire mesh at the conduit location, ensure that both ends of the wire mesh extend 100mm beyond both sides of the conduit; when opening grooves in the masonry wall, ensure that the groove dimensions meet the following requirements: groove depth ≤ dn + 10mm, groove width ≤ dn + 60mm, where dn represents the conduit diameter.

[0046] Construction to prevent cracking of masonry mortar joints The masonry wall should be constructed in sections, with a daily construction height not exceeding 1800mm to reduce horizontal cracks in the middle of the wall caused by instability at the bottom and swaying at the top. The sloping top bricks should be laid 7 days after the initial construction of the main masonry wall to prevent shrinkage and settlement that could create voids due to insufficient interval between laying the top bricks. When laying the sloping top bricks, precast triangular blocks (made of cement) with an angle of 45-60 degrees should be placed at both ends of the top of the masonry wall to ensure the sloping top bricks are laid at an angle of 45-60 degrees, preventing them from being too large or too small and thus failing to effectively tighten. To prevent gaps between the sloping top bricks and the bottom of the beam, which could lead to cracks during later plastering, the exterior walls and sloping top brick areas should be grouted twice to ensure a tight seal. Other walls should be grouted as needed during construction, with the grooving done before the mortar initially sets (generally, grooving should begin after the third course of bricks, working on the two joints below the third course). During grooving, a round steel pipe should be pulled back and forth twice to ensure a tight seal. When the sloping top bricks reach 20-30mm from the bottom of the beam, micro-expansion cement should be used to fill the gap between the top of the sloping top bricks and the bottom of the beam to prevent shrinkage cracking.

[0047] Construction to prevent herringbone cracks at the corners of the window sill: During wall construction, a concrete coping (using C15 concrete) is constructed at the top of the window sill. The width and thickness of the concrete coping are both 100mm, and the length of the concrete coping is no more than 1.5m. When the length is greater than 1.5m, reinforcement is added to the concrete coping. Both ends of the concrete coping extend into the wall from the top of the window sill by no less than 100mm. The concrete coping can prevent herringbone cracks from forming at the four corners around the window opening.

[0048] Construction crack prevention measures for walls at construction opening locations: Install a precast concrete lintel (at least 100mm thick) at the top of the construction opening to prevent insufficient reinforcement rigidity from causing the opening to bend and crack at both ends; when the sides of the construction opening lack toothed joints or the toothed joints are less than 200mm, embed tie bars with hooked ends every 500mm along the height of the construction opening on both sides (see reference). Figure 5 The tie bars extend 500mm beyond the construction opening and are embedded 300mm into the masonry wall to prevent cracking at the junction of old and new masonry. When plastering the masonry walls on both sides of the construction opening, leave a 150mm area around the opening unplastered. After the construction opening is built, install wire mesh at the opening and extend it to the reserved area around the opening, overlapping it with the wire mesh on the masonry wall around the opening. Then plaster the opening to prevent cracking at the junction of old and new masonry or at the construction opening.

[0049] Construction of post-pouring strip for crack prevention in basement roof slab A separate support system is installed at the post-pouring strip of the basement roof slab, with a separate formwork for the basement roof slab support system. The support system is removed after the post-pouring strip is poured and reaches the design strength, in order to prevent the support system at the post-pouring strip of the basement roof slab from being removed too early, which would cause the post-pouring strip of the basement roof slab to bear heavy loads too early and crack.

[0050] Construction of basement exterior shear wall to prevent vertical cracking The basement exterior shear wall is a shear wall along the perimeter of the basement adjacent to the excavation pit. During construction, the basement exterior shear wall and the retaining wall use the same grade of concrete. When different grades of concrete are used, the retaining wall and the basement exterior shear wall should be at least 100m apart, and the retaining wall and the basement exterior shear wall should be separately formworked and poured separately. When the basement exterior shear wall is connected to the retaining wall, the curing of the concrete of the basement exterior shear wall should be strengthened to ensure that the curing time is not less than 72 hours. At the part where the retaining wall and the basement exterior shear wall are connected, the tie rods should be loosened first (but the formwork should not be removed), and a perforated water pipe should be placed on the top of the retaining wall for continuous watering, so that the water enters the gap between the formwork and the concrete along the slab joint to keep the concrete surface moist and cured.

[0051] Basement overall waterproofing construction This includes both the design and construction phases. In the design phase, expansion joints and post-cast strips should be appropriately designed. Expansion joints should be installed when the length of the cast-in-place basement structure exceeds approximately 30m. Expansion agents should be added to the concrete to compensate for shrinkage stress, or crack-resistant fibers (such as PP fibers) should be added. Crack-resistant fibers have a certain tensile strength and good bond with concrete, enhancing tensile stress during the hardening process and controlling crack formation. Crack-resistant reinforcing bars should be installed, and structural reinforcement should be increased to improve crack resistance. Horizontal reinforcement in the basement exterior walls should use small diameter and small spacing as much as possible to allow the structural reinforcement to function as temperature reinforcement, effectively improving crack resistance.

[0052] During the construction phase (1) Rational selection of raw materials Low heat of hydration cement is used, preferably 42.5 grade slag silicate cement, with appropriate amounts of ultrafine fly ash and high-efficiency water-reducing agents added to reduce cement usage and improve the pumpability of concrete. Clean medium sand is used, with the mud content controlled to not exceed 3%. Continuously sized pebbles or crushed stone are used. Admixtures and additives are employed. The use of water-reducing agents can improve the workability of the concrete mixture, reduce the water-cement ratio, reduce water usage, and prevent excess water in the concrete from causing cracks and voids. Additives can replace a portion of the cement, reducing the heat of hydration and decreasing temperature and shrinkage cracks in the concrete.

[0053] (2) Strictly control the concrete mix proportion and slump; the slump is selected according to different parts of the basement and construction process, and the amount of cement, admixtures and additives is strictly controlled to ensure sufficient fine aggregate to make the mixture have good workability.

[0054] (3) Maintenance After the concrete is poured, it should be covered and cured with heat insulation within 12 hours, and then the concrete surface should be kept warm and moist for 14 days to prevent shrinkage cracks and temperature cracks. For large-volume concrete, temperature control measures should be taken to control the internal and external temperature difference to ≤25℃ and temperature measurement records should be kept.

[0055] (4) Leakage control during basement construction During formwork construction, ensure the formwork is sturdy and the joints are tight to prevent grout leakage; weld water-stop rings to the tie bolts of the formwork; during concrete pouring, strictly control the free fall of the concrete to prevent stratification and segregation; pour concrete in layers and sections, ensuring that the time interval between pouring layers and sections does not exceed the initial setting time to avoid construction joints; increase the amount of concrete vibration to prevent under-vibration and complete the pouring and vibration of the upper layer of concrete before the initial setting of the lower layer, inserting the vibrator 5-10cm into the lower layer of concrete to ensure the quality of the concrete at the joint; the vibration time is based on the concrete starting to show grout and air bubbles.

[0056] (5) Construction of waterproofing for basement post-pouring strips and construction joints During the waterproofing construction of the post-cast strip in the basement, a waterstop steel plate is installed at the edge of the first-cast concrete. The waterstop steel plate is positioned at 1 / 2 the thickness of the first-cast concrete wall, with a embedment depth of 1 / 2 the width of the waterstop steel plate. The two wings of the waterstop steel plate are bent towards the water-facing side (reference). Figure 6 To extend and alter the water seepage path and enhance the anti-seepage effect, when pouring concrete after the initial pour, a higher grade of concrete and a micro-expansion agent are used. In the construction joint anti-seepage construction of the basement, the horizontal construction joint on the basement sidewall is located 300mm above the basement floor slab and is poured simultaneously with the floor slab. During construction, a water-stop steel plate is installed at the horizontal construction joint. The water-stop steel plate is positioned at 1 / 2 the thickness of the basement sidewall, with a embedment depth of 1 / 2 the width of the water-stop steel plate. The two wings of the water-stop steel plate are bent towards the water-facing side (see reference). Figure 7 ).

[0057] (6) Embedded parts treatment: For embedded parts that penetrate the exterior wall, a water-stop ring shall be welded on each embedded part; the embedded parts that penetrate the formwork shall be tightly sealed to prevent leakage of grout; when pouring concrete, avoid the occurrence of voids and honeycomb in the concrete below the embedded parts.

[0058] (7) Repair measures after basement leakage After locating the leak point and leak line by chiseling, the leak is plugged using the filling method or grouting method. When there is leakage around the embedded part, after chiseling to a certain depth around the embedded part, the leak is plugged with a quick-setting agent. When plugging the leak using the filling method, the crack is widened with a steel chisel or a high-speed rotating cutting disc to form a V-shaped or trapezoidal groove. After cleaning, epoxy mortar, cement mortar, asphalt paste, polymer sealant or various ready-made leak-stopping agents are applied in layers to seal the crack. When the repaired crack has structural strength requirements, epoxy mortar is used for filling.

[0059] Kitchen and bathroom waterproofing construction Kitchen waterproofing primarily involves flue waterproofing, which includes roof flue waterproofing and floor-level flue waterproofing. Roof flue waterproofing includes: during roof construction, a roof flue curb is poured in the flue construction area. This curb is poured along with the roof concrete to prevent rainwater from entering the flue from the base and causing leaks. The curb height should be at least 300mm. Floor-level flue waterproofing involves installing an indoor flue curb (150mm high, 80mm wide, C20 plain concrete) at the base of the indoor flue before plastering the kitchen walls. This prevents leakage from the top of the lower kitchen's flue during the upper kitchen's renovation. The indoor flue curb construction is carried out simultaneously with sealing the surrounding flue openings to enhance waterproofing. The indoor flue curb... Figure 8 As shown. For flues and exhaust ducts in the bathroom, a 150mm wide C20 concrete curb with a height 50mm higher than the top surface of the sump cover should be constructed around the base of the corresponding flue or exhaust duct. When there is no sump in the bathroom and only a lowered slab is installed, the concrete curb at the base of the flue or exhaust duct in the bathroom does not need to be constructed, but waterproofing measures must be taken within a 300mm radius around the base of the flue or exhaust duct, and a water tightness test must be conducted.

[0060] Construction of bathroom recessed sump to prevent cracking and leakage The bottom slab of the caisson is thickened by 10-20mm, and the beams around the bottom slab are vibrated twice to ensure compaction. When constructing the upper caisson, the formwork supports should be placed on the beams on both sides of the lower caisson, avoiding support on the bottom slab to prevent cracking. Double rows of timber should be used for the support on the beams on both sides of the lower caisson. During the construction of the cast-in-place caisson, horizontal iron bars are installed at the four corners of the bottom of the side formwork. These horizontal iron bars are welded to the stirrups of the beams outside the space enclosed by the side formwork (see reference). Figure 9 This ensures that the caisson side formwork maintains the preset installation elevation, avoiding the need to nail wooden strips to the outside of the caisson side formwork for support, and preventing the risk of water seepage due to the difficulty in removing the wooden strips during the dismantling of the caisson side formwork; conversely, the caisson side formwork is symmetrically fixed with wooden beams (see reference). Figure 10 , Figure 11In addition, triangular plates are installed between adjacent caisson side molds at the four corners for reinforcement. Compared with the existing method of fixing the caisson side molds with wires that penetrate the caisson bottom plate, the method of fixing the caisson side molds with wooden beams in a longitudinal and transverse manner and using triangular plates for reinforcement does not penetrate the caisson bottom plate. It also avoids the formation of leakage channels by pulling the wires when dismantling the molds and avoids the wires rusting and forming leakage channels, thus improving the anti-leakage effect in the cast-in-place construction of the caisson.

[0061] Waterproofing construction at the base of interior walls For masonry walls, solid bricks and cement mortar should be used to construct the base of the wall within a 200mm height. When hollow cement bricks are used, they should be filled with fine aggregate concrete. Avoid using autoclaved aerated concrete bricks to prevent moisture from rising from the ground and causing mold and peeling of the paint on the wall base. Construct a 200mm high plain concrete curb at the base of the wall where the balcony / terrace meets the interior. The length of the plain concrete curb should be set according to the full length of the wall, and the width should be the wall thickness. When the plain concrete curb is constructed using a two-stage pouring method, pre-embed reinforcing bars with a spacing of 100mm and a height in the construction area of ​​the plain concrete curb in the floor slab and roughen the surface before pouring the plain concrete curb to prevent water from the balcony / terrace from seeping into the interior. The concrete curb at the base of the bathroom wall is 200mm high, with the same width and length as the wall thickness. When pouring the secondary concrete curb for the sunken area, pre-embed reinforcing bars at 200mm intervals around the curb (the reinforcing bars are pre-embedded during floor slab construction), with the exposed ends extending 100mm beyond the floor slab surface. The floor slab should be roughened and cleaned before pouring the concrete curb. When the bottom of the air conditioner unit contacts the room floor, a plain concrete curb with a height of 200mm should be poured around the bottom of the air conditioner unit.

[0062] Exterior wall waterproofing construction Exterior wall waterproofing construction includes waterproofing of bolt holes, expansion joints, and brickwork. Bolt hole waterproofing includes: when installing bolts to fix the exterior wall formwork, ensuring the inner end of the bolt is 10-20mm higher than the outer end to prevent water from flowing in from the outside due to inadequate sealing; after removing the formwork and bolts, seal the bolt holes with waterproof mortar containing a micro-expansion agent, compacting and smoothing the mortar with a round steel bar. After the mortar dries, apply two coats of polyurethane waterproof coating to the bolt holes on the outer side (see reference). Figure 12 The coating shape is a circle centered on the bolt hole. The diameter of the first coat is 10cm, the diameter of the second coat is 6cm, and the overall coating thickness is 1.5mm.

[0063] The construction of waterproofing for exterior wall expansion joints includes: pre-reserving expansion joints at the location of the concrete beams in the exterior wall; applying waterproof material (preferably polymer cement elastic waterproof coating) to the plaster surface 100mm above and below the expansion joints, ensuring the overlap width; if the expansion joints are for decoration, special grout for exterior wall tiles or stone paint can be used to decorate the expansion joints; if the expansion joints are for the thermal expansion and contraction of the plaster layer, weather-resistant sealant is used for filling, ensuring the joint is dry and clean during filling, and the sealant must be fully applied without any leakage; when using pre-made plastic expansion strips for exterior wall expansion joints, remove the pre-made plastic expansion strips after plastering is completed, apply two layers of waterproofing to the joint, and then fill with weather-resistant sealant to avoid gaps between the pre-made plastic expansion strips and the plaster layer that could lead to leakage.

[0064] The construction of waterproofing for exterior wall tiles includes: using a special adhesive to bond the exterior wall tiles, employing a thin and full grouting process, and grouting twice during bonding to avoid negative pressure effects in cavities and to prevent pinholes and pores, thereby preventing outdoor water from seeping into the room through cavities, pinholes, and pores during the rainy season.

[0065] Roof waterproofing construction Roof waterproofing construction includes waterproofing of the roof panels and waterproofing of roof expansion joints. Roof panel waterproofing includes: after the roof structure is completed, a 24-hour water tightness test is conducted to ensure no leakage. Then, a waterproof layer is applied, followed by another 24-hour water tightness test. A leveling layer is then applied on top of the waterproof layer, with expansion joints cut or left in 3000*3000mm squares, 10-15mm wide. Expansion joints are left or cut 200mm around structures (such as flues or the perimeter of parapet flashing), with the same width as the expansion joints. Expansion joints are installed at the external corners of roof structures (such as pergolas or columns), aligned with or perpendicular to them (see reference). Figure 13 To prevent diagonal cracks caused by concentrated constraint forces at the external corners of the roof structure, thus avoiding potential water seepage hazards; after ensuring the expansion joints and partition joints are clean and dry, fill them with weather-resistant sealant or modified asphalt. Before constructing the leveling layer, install a continuous drainage ditch around the perimeter of the roof (inside the parapet wall and outside the roof threshold area), avoiding side drains with an arc shape. Water in the ditch is drained through a PVC drain pipe (20mm in diameter) through the parapet wall and connected to the external rainwater downpipe, with the PVC drain pipe extending 100mm into the rainwater downpipe; the ditch cross-section is 150mm (width) × 25mm (height), and pebbles with a particle size of 5-8mm are laid inside the ditch, wrapped with non-woven fabric; after the ditch is installed, cover the top of the ditch with two layers of non-woven fabric to prevent fine stone concrete from leaking into the ditch and causing blockage when the leveling layer is poured.

[0066] The construction of waterproofing for roof expansion joints includes: When constructing the top floor slab, simultaneously construct concrete reverse edges on both sides of the roof expansion joint slab. A horizontal edge is integrally constructed on the top of the first concrete reverse edge, extending horizontally to form the second concrete reverse edge (the first and second concrete reverse edges are opposite each other). The bottom of the horizontal edge and the top of the second concrete reverse edge are spaced a certain distance (no more than 30mm). (Reference) Figure 14 The gaps between the sections are filled with weather-resistant sealant. The top of the first and second concrete inverted edges (both reinforced with steel bars) is constructed 300mm higher than the finished roof surface to prevent rainwater from being scraped directly into the expansion joints and to avoid water seepage into the walls of the rooms on the top floor closest to the expansion joints. A triangular inverted edge is also installed at the bottom of the end of the horizontal edge closest to the first concrete inverted edge to further improve the waterproofing effect.

[0067] Pipe opening leak prevention construction During the construction of the floor slab, pipe openings are reserved in the area where drainage pipes pass through. When installing pipes through these openings, the openings are roughened. Two or more waterproof rubber rings are fitted onto each drainage pipe to improve the adhesion between the pipe and the concrete, preventing cracks and leaks at the joint surface. The waterproof rubber rings are positioned corresponding to the pipe openings. After the drainage pipe passes through the opening, a bottom formwork is installed at the bottom of the opening. Reinforcing steel supports are installed at the bottom of the bottom formwork. One end of the reinforcing steel supports supports the bottom formwork, and the other end supports the flange ring of the drainage pipe. Multiple reinforcing steel supports are arranged circumferentially along the flange ring (see reference). Figure 15 By setting steel reinforcement at the bottom of the opening formwork, it is avoided to set wire hoisting formwork at the top of the opening formwork, thus preventing the wire from penetrating the floor slab at the pipe opening and causing leakage at the wire location; when pouring concrete for the pipe opening, fine stone concrete with 3% micro-expansion agent is used and poured in two stages to reduce shrinkage and improve waterproof performance. If cracks are caused by shrinkage during the first pour, the second pour can repair the shrinkage caused by the first pour.

[0068] Construction of Leak-proof Drainage Pipes for Bathroom Recessed Areas After the drain pipes (vertical and horizontal pipes) at the pre-designated locations in the bathroom recessed area are installed and the pipe openings are sealed, waterproofing of the recessed area is carried out. After a water test confirms no leakage, a 100mm high retaining wall is built around the drain pipes using solid bricks, according to the length and width dimensions of the pipe well (for reference). Figure 16 The inverted sills are arranged in a rectangular shape. Then, C20 plain concrete is used to construct a waterproof inverted sill to the preset height to prevent water in the caisson from backflowing towards the pipe opening and to enhance the anti-leakage effect of the pipe opening. When arranging drainage pipes in the caisson, the side drain (secondary drain) is installed on the drainage riser and is installed at the lowest point of the caisson. Avoid installing the side drain on the drainage branch pipe to prevent sanitary ware drainage from flowing into the caisson through the secondary drain.

[0069] The above description is merely a detailed illustration of specific embodiments of the present invention and is not intended to limit the invention. Various substitutions, modifications, and improvements made by those skilled in the art without departing from the principles and scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for preventing cracking and leakage in residential buildings, characterized in that, include: Floor slab crack prevention construction The water-cement ratio of the floor slab concrete should not exceed 0.5, the maximum amount of fly ash or mineral powder should be 25% of the cement content, and the on-site slump of the floor slab concrete should not exceed 180mm; during floor slab construction, at least two layers of formwork support should be maintained; when pump pipes penetrate pump pipe holes in floor slabs that are less than 28 days old, a flexible material with a thickness of not less than 50mm should be wrapped around the pump pipe, with the flexible material located between the pump pipe and the pump pipe hole. Wall crack prevention construction This includes crack prevention construction for wall plastering, crack prevention construction for walls at the junction of different materials, crack prevention construction for wall surface conduit locations, and crack prevention construction for masonry mortar joints; Basement crack prevention and leakage prevention construction This includes preventing cracking of the post-cast strip in the basement roof slab, preventing vertical cracking of the basement exterior shear walls, and preventing overall leakage in the basement. Flue waterproofing construction This includes roof flue waterproofing construction and floor flue waterproofing construction; roof flue waterproofing construction includes: when constructing the roof, pouring roof flue sills in the flue construction area on the roof. The roof flue sills are poured together with the roof concrete, and the height of the roof flue sills is not less than 300mm. The construction of the flue waterproofing on each floor includes: before plastering the kitchen wall, setting an indoor flue curb at the base of the indoor flue. The construction of the indoor flue curb is carried out together with the sealing of the openings around the flue. The indoor flue curb has a cross-section of 150mm high and 80mm wide and is constructed with C20 plain concrete. Construction of bathroom recessed sump to prevent cracking and leakage Thicken the bottom plate of the caisson by 10-20mm, and vibrate the beams around the bottom plate of the caisson twice until they are compacted. When constructing the upper caisson, support the formwork of the upper caisson on the beams on both sides of the lower caisson. During the installation of the caisson side formwork, set horizontal iron at the four corners of the bottom of the caisson side formwork, and weld the horizontal iron to the stirrups of the beam outside the space enclosed by the caisson side formwork. Fix the opposite caisson side formwork with wooden beams in a longitudinal and transverse symmetrical manner, and set triangular plates between adjacent caisson side formwork at the four corners for reinforcement. Waterproofing construction at the base of interior walls After constructing a 200mm high retaining wall at the base of the wall, proceed with the subsequent wall construction on the retaining wall. Exterior wall waterproofing construction This includes waterproofing construction for bolt holes in exterior walls, waterproofing construction for expansion joints in exterior walls, and waterproofing construction for brickwork in exterior walls. Roof waterproofing construction This includes waterproofing construction of roof panels and waterproofing construction of roof expansion joints. Pipe opening leak prevention construction During the construction of the floor slab, pipe openings are reserved in the area where drainage pipes pass through the floor slab. After roughening the pipe openings, two or more waterproof rubber rings are fitted on each drainage pipe. Then, the pipes are passed through the pipe openings and the waterproof rubber rings are positioned in the direction of the pipe opening height. A bottom formwork is set at the bottom of the pipe opening, and steel reinforcement supports are set at the bottom of the bottom formwork. One end of the steel reinforcement supports the bottom formwork, and the other end of the steel reinforcement supports the flange ring of the drainage pipe. Multiple steel reinforcement supports are arranged circumferentially along the flange ring. Construction of Leak-proof Drainage Pipes for Bathroom Recessed Areas After the drain pipes at the pre-set locations in the bathroom sump are installed and the pipe openings are sealed, the sump is waterproofed. After a water test confirms no leakage, a 100mm high curb is built around the drain pipes using solid bricks. Then, C20 plain concrete is used to construct a waterproof curb to the pre-set height. When arranging the drain pipes in the sump, the side drains are installed on the drain risers, and the secondary drains are installed at the lowest point of the sump.

2. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, In the construction of the floor slab crack prevention, when the floor slab thickness is no more than 120mm and the floor slab reinforcement is a single layer of reinforcement, in the area where the conduit is laid, a 4mm@200*200 steel mesh or 6mm steel bar is laid under the conduit. When laying the reinforcement, the spacing between adjacent reinforcement bars is 300~350mm, and the two ends of the steel mesh or steel bar in the width direction extend 300mm from both sides of the conduit. Before pouring the floor slab concrete, place F-type or H-type precast concrete blocks in areas of the floor slab construction area that do not require waterproofing to control the thickness of the floor slab. The strength and thickness of the precast concrete blocks are the same as the strength and thickness of the floor slab. Place no less than 5 precast concrete blocks on each floor slab and no less than one precast concrete block in the center of the floor slab. During the concrete pouring process, ensure that the concrete is vibrated and compacted. After pouring, within 1 / 2 to 2 / 3 of the initial setting time of the concrete, mechanically grind the surface of the slab to finish the grout. When the concrete strength reaches 1.2 MPa or above, walk on the slab surface and install formwork and formwork supports.

3. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, The wall plastering anti-cracking construction includes: wetting the ceiling and wall with water, then roughening the surface, curing with water for two days after roughening, and then plastering. The cement slurry for roughening should have a mix ratio and viscosity that meet the requirements of being able to roughen without dripping. The spacing between two adjacent roughened sections should not exceed 50mm. The roughening mortar should be used up within 2 hours. When plastering the wall, the plastering mortar should be used up within 2 to 3 hours. Construction to prevent cracking at the junction of different materials includes: roughening the surface at the junction of different materials and then hanging wire mesh, so that the roughness lifts the wire mesh, and then plastering is done after the wire mesh is separated from the masonry wall by a certain distance, so that the wire mesh is in the middle of the plaster mortar layer; for the top floor of the building, the wire mesh is fully hung on the inside of the exterior wall of the top floor before plastering. The construction process for preventing cracking of conduit locations on walls includes: installing conduits on the wall using pre-reserved, pre-embedded, or mechanically grooved or drilled methods; when opening grooves in masonry walls, ensuring the groove dimensions meet the following requirements: groove depth ≤ dn + 10mm, groove width ≤ dn + 60mm, where dn represents the conduit diameter; after the conduit is installed, filling the grooves tightly with cement mortar.

4. The construction method for preventing cracking and leakage in residential buildings according to claim 3, characterized in that, The construction method for preventing cracking of masonry mortar joints includes: constructing masonry walls in sections, with the daily construction height not exceeding 1800mm; laying sloping top bricks after a 7-day interval between masonry wall constructions, and setting prefabricated triangular blocks with an angle of 45-60 degrees at both ends of the top of the masonry wall when laying the sloping top bricks; grouting the outer walls and sloping top brick sections twice until they are dense, and grouting the other walls as needed during construction, with the grouting done before the mortar initially sets; when the sloping top bricks are laid to 20-30mm below the bottom of the beam, filling the gap between the top of the sloping top bricks and the bottom of the beam with micro-expansion cement.

5. The construction method for preventing cracking and leakage in residential buildings according to claim 3, characterized in that, The wall crack prevention construction also includes the construction of the window sill corner anti-V-shaped crack construction: during the wall construction, a concrete capping is constructed at the top of the window sill, the concrete capping is reinforced, and both ends of the concrete capping extend into the wall from the top of the window sill by not less than 100mm. The wall crack prevention construction also includes crack prevention construction at the construction opening location: a precast concrete lintel is set at the top of the construction opening; when the toothed joints are not made on both sides of the construction opening, tie bars with hooks are embedded every 500mm along the height direction of the construction opening on both sides of the construction opening, with the tie bars extending 500mm out of the construction opening and 300mm embedded in the masonry wall; when plastering the masonry wall on both sides of the construction opening, a 150mm area around the construction opening is left unplastered; after the construction opening is built, a wire mesh is set at the construction opening, and the wire mesh extends to the reserved area around the construction opening and overlaps with the wire mesh on the masonry wall around the construction opening before plastering the construction opening.

6. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, During the construction of the anti-cracking method for the post-pouring strip of the basement roof slab, a separate support system is set up at the post-pouring strip of the basement roof slab. The formwork is separated from the basement roof slab support system and is removed after the post-pouring strip is poured and the strength meets the design requirements. The basement external shear wall is a shear wall located around the perimeter of the basement near the excavation pit. During construction, the basement external shear wall and the retaining wall use the same grade of concrete. When different grades of concrete are used, the retaining wall and the basement external shear wall are spaced at least 100m apart, and the retaining wall and the basement external shear wall are separately formworked and poured separately. When the basement external shear wall is connected to the retaining wall, the curing of the concrete of the basement external shear wall is strengthened to ensure that the curing time is not less than 72 hours. At the part where the retaining wall and the basement external shear wall are connected, the tie rods are loosened first but the formwork is not removed. A perforated water pipe is placed on the top of the retaining wall for continuous watering, so that the water enters the gap between the formwork and the concrete along the joint of the formwork to keep the concrete surface moist and cured.

7. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, The construction of the external wall bolt hole anti-seepage construction includes: when installing bolts for fixing the external wall formwork, the inner end of the bolt is 10-20mm higher than the outer end of the bolt; after the external wall formwork and bolts are removed, the bolt holes are sealed with waterproof mortar containing micro-expansion agent, and the waterproof mortar is compacted and smoothed with round steel. After the waterproof mortar dries, polyurethane waterproof coating is applied to the bolt holes on the outer side, with two coats. The shape of the coating is a circle centered on the bolt hole. The diameter of the first coat is 10cm and the diameter of the second coat is 6cm. The overall coating thickness is 1.5mm. The construction of the waterproofing of the external wall partition joint includes: reserving the external wall partition joint at the location of the external wall concrete beam, applying waterproof material to the plaster surface 100mm above and below the external wall partition joint, and densely filling the partition joint with grout; when the external wall partition joint uses a prefabricated plastic partition strip, after the plastering is completed, the prefabricated plastic partition strip is removed, and after applying two layers of waterproofing to the joint, it is filled with weather-resistant sealant. The construction of the exterior wall brick waterproofing includes: the exterior wall facing bricks are pasted with a special adhesive. During the pasting process, a thin mortar and full mortar construction technique is used, and the joints are grouted twice during the pasting process to avoid cavities, sand holes and gaps.

8. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, The waterproofing construction of the roof panel includes: after the roof structure is completed, a water tightness test is conducted for 24 hours to ensure that the roof structure does not leak. Then, a waterproof layer is applied to the roof. After another water tightness test for 24 hours, a leveling layer is applied on top of the waterproof layer. The leveling layer is divided into sections, which are cut or left in 3000*3000mm squares with a joint width of 10~15mm. Expansion joints are left or cut at 200mm around the perimeter of the structure, with the expansion joints being the same width as the section joints. During the construction of the section joints, section joints are set at the external corners of the roof structure, aligned with or perpendicular to them. Before the leveling layer is constructed, a continuous drainage ditch is set up around the perimeter of the roof, avoiding the side drains in an arc shape. The water in the ditch is connected to the rainwater downpipe on the exterior wall through a PVC drainage pipe that extends 100mm into the rainwater downpipe. Pebbles with a particle size of 5-8mm are laid in the ditch and wrapped with non-woven fabric. After the ditch is installed, two layers of non-woven fabric are placed on top of it.

9. The construction method for preventing cracking and leakage in residential buildings according to claim 1, characterized in that, The construction of the roof expansion joint waterproofing includes: when constructing the top floor slab, simultaneously constructing concrete reverse edges on both sides of the roof expansion joint, and integrally constructing a horizontal edge on the top of the first side concrete reverse edge, with the horizontal edge extending horizontally to form the second side concrete reverse edge, and the bottom of the horizontal edge and the top of the second side concrete reverse edge being a certain distance apart, with weather-resistant sealant used to fill the gap.

10. The construction method for preventing cracking and leakage in residential buildings according to any one of claims 1 to 9, characterized in that, During the construction of the pipeline opening for seepage prevention, when pouring the concrete at the pipeline opening, fine stone concrete with 3% micro-expansion agent is used and poured in two stages to reduce shrinkage.

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