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Cause analysis and prevention measures of the most easily leaking parts of const
Update time：2017-09-08 00:34:32clicks：2042次Type size：T|T
The following are the parts prone to leakage to take effective measures, engineering construction should be strictly checked:
1, prevent roof leakage;
2. Prevent basement leakage;
3, prevent kitchen leakage;
4, to prevent external Windows and doors, leakage;
5, prevent water supply and drainage pipes and other parts of leakage.
The reasons for its leakage are mostly caused by the following reasons:
One is: the material is unqualified; The second is: the design node is not detailed; Third, the operator's sense of responsibility is not strong; Fourth, the protection of finished products is not good.
► Leakproof basement
1. Reason analysis
From the current point of view, there are two factors affecting the quality of waterproof engineering, especially underground waterproof engineering, one is the design problem, the other is the construction problem.
The current design of the waterproof project only talks about what materials to use and determine the waterproof grade of the project, and rarely draws the node method and details (refer to the standard atlas). This does not standardize some practices of waterproof engineering from the source;
The second is the problem of construction. After the construction unit, especially the general contractor, undertakes the project, it only finds a qualified waterproof construction unit to subcontract the construction according to the regulations. However, as for how to conduct joint review of drawings in the early stage of the project, the identification of materials and the preparation and review of construction plans according to the specific conditions of the project (including the construction environment and climate, working conditions, the level of underground water level and whether the groundwater has erosion effect, etc.), the main technical links have not been paid as much attention as in the construction of the main project. In the construction, there are few follow-up inspections and side station supervision, so many details are not properly handled, leading to problems on the completion of the project, and serious direct impact on the use of. At this time, the construction unit then spends a lot of manpower and material resources to carry out maintenance (and the effect is often not good), which not only affects the reputation of the construction unit, but also increases the project cost.
2. Prevention and control measures
(1) The underground waterproofing project should follow the principle of multi-channel fortification and balancing hardness and softness; The principle of detailed waterproofing should be carefully constructed.
Self-waterproofing of concrete structure is a kind of waterproofing method which realizes the waterproofing function based on the compactness of engineering structure itself. The underground waterproofing of high-rise buildings basically adopts three fortifications, namely, concrete structure waterproofing (self-defense) + outsourcing flexible waterproofing layer + lime soil auxiliary waterproofing layer. The self-waterproofing of the structure is the key to anti-leakage, which must be strictly monitored and accepted.
1, pay attention to vibration compaction, can not leak vibration;
2. After the concrete pouring is completed, it should be covered with a straw curtain in time and sent for maintenance for not less than 14 days;
3, multi-way fortification, the principle of hardness and tenderness.
At present, the more common practice is to paste waterproof coil or paint waterproof layer on the waterfacing surface of the engineering envelope structure to make a protective layer, and then backfill and do ground waterproof.
(2) Strengthen the waterproof treatment and process control of the detailed structure
The detailed structure mainly includes: construction joints, deformation joints, after pouring belt, embedded bolts, prearranged iron parts, through the wall casing and so on. If these parts are not handled well, it is easy to produce leakage, and the engineering industry has the so-called "ten cracks and nine leaks", and the engineering (supervision) personnel must strictly check the process.
At present, the construction joint, deformation joint, after pouring belt often adopt the practice of water stop, water stop commonly used steel plate water stop and BW rubber water stop effect is better, the operation is relatively simple, but the buried part must meet the design requirements. During the construction of the steel plate water stop belt, attention should be paid to the lap, the weld surface should be welded, and the corner should be strictly treated; A good sealing steel plate should be firmly fixed with the steel bar of the wall (or plate). The steel plate should be straight and not twisted; BW rubber sealing strip immersed in water, expansion rate of 100 ~ 500%, convenient construction, clean the concrete surface, tear off the BW sealing strip isolation paper, use the viscosity of the material itself, stick to the surface of concrete, winter paste force is low or used for vertical stitching, can be separated by 1 meter nail a steel nail, fixed, and then you can pour concrete. The application of BW water seal simplifies the construction process of construction joint, and the water seal performance is reliable.
1. The construction of the buried water stop belt in the deformation joint shall comply with the following provisions
(1) The water stop should be buried accurately, and the hollow ring should coincide with the center line of the deformation joint;
(2) The water stop belt should be fixed firmly, the inner water stop belt of the top and bottom plate should be installed in a "basin shape", and the water stop belt should be fixed with special steel sleeves or flat steel. When flat steel is used for fixing, the end of the water stop strip should be clamped with flat steel first, and the flat steel should be welded with the steel bars in the structure. The spacing of bolts for fixing flat steel should be 500mm;
(3) The middle buried water stop belt is first poured on the concrete side, and its end mold should be firmly supported and strictly prevent leakage;
(4) The joint of the water stop belt should be one place, should be located on the higher position of the side wall, should not be located at the corner of the structure, and the joint should be welded by hot pressure;
(5) The buried water stop belt should use right Angle special accessories at the turning point, and should be made into a circular arc, the corner radius of the rubber water stop belt should be not less than 200mm, the steel edge rubber water stop belt should be not less than 300mm, and the corner radius should be increased with the width of the water stop belt;
(6) It is appropriate to use water expanded rubber ordinary composite rubber strip, water expanded rubber strip with steel wire or fiber fabric in the middle, and hollow ring type water expanded rubber strip. When the water expansion rubber strip is used, effective fixing measures should be taken to prevent the water stop strip from expanding out of the joint.
2. The construction of the post-casting belt shall comply with the following provisions
(1) The pouring time of the post-pouring belt, when there is no design requirement, should be poured after the concrete age on both sides reaches two months, but the post-pouring belt of high-rise buildings should be carried out after the structure is closed;
(2) Before the concrete construction of the post pouring belt, the post pouring belt should be protected if it is an external type water stop belt to prevent mixing debris and damage to the external type water stop belt;
(3) The post-casting belt should be constructed with compensated shrinkage concrete, and its strength grade should not be lower than that of the concrete on both sides;
(4) The curing time of the concrete after pouring shall not be less than 28d.
3. Wall tube (box)
At the place where the pipe passes through the waterproof structure, the casing should be embedded, and the water sealing ring should be welded on the casing, and the welding should be strict. When the number of water sealing rings is installed according to the design requirements, the pipe should first pass through the embedded pipe fitting, and the position should be identified for temporary fixing. Then the casing should be welded firmly with sealing steel plate at one end, and the gap between the casing and the pipe at the other end should be filled tightly with waterproof sealing material. And seal the sealing plate tightly.
(1) Wall bolts:
In order to solve the hidden danger of water seepage left by the wall piercing bolts, disposable waterproof bolts should be used in the basement external wall formwork. The water seal ring shall be made of 4mm thick steel plate with a diameter of 80mm, and shall be soldered firmly with the bolts. After removing the template for the exterior bolts, chisle 40mm deep holes at the roots of the outer bolts, burn the bolts with gas welding, and compact the holes with waterproof mortar.
(2) Detailed structure of wall pipe (box) :
(1) The wall pipe (box) should be embedded before concrete pouring;
② The distance between the wall tube and the inner corner and the concave and convex part should be greater than 25mm;
(3) The pipe through the wall should adopt the casing type waterproof method, and the water sealing ring should be welded outside the casing;
(4) When there are more pipelines through the wall, they should be relatively concentrated and the wall box method should be used. The sealing steel plate of the wall box shall be welded tightly with the embedded Angle steel on the wall, and the modified asphalt flexible sealing material or fine stone concrete shall be injected into the reserved pouring hole on the steel plate for treatment.
(3) Through the wall pipe (box) waterproof construction, through the wall pipe waterproof construction should comply with the following provisions:
① When the casing type wall pipe waterproof structure is used, the wing ring and the casing should be fully welded and dense, and the casing surface should be cleaned before construction;
② The spacing between tubes and tubes should be greater than 300mm;
(3) When the project has protection requirements, in addition to effective waterproof measures, the wall pipe should also take measures to meet the protection requirements (Figure 1, Figure 2).
► Exterior wall is leakproof
Residential engineering external wall leakage phenomenon is more common, rainwater through the external wall cracks into the wall, resulting in the interior wall decorative surface layer mildew, and even cause the paint layer shell, fall off, affect the use of function, serious will cause short circuit wire, resulting in accidents, to the user to bring a certain economic loss and cause disputes, should take effective measures to solve.
1. Leakage caused by design factors
(1) Reason analysis
1, the designer does not pay attention to the details of the large design, such as windowsill slope, eagle mouth, drip tank, through the wall pipe, external wall embedded pipe fittings, aluminum doors and Windows, curtain wall and wall joints;
2, for the sake of beauty, the exterior wall decorative brick (small) is designed into a thin seam splicing, so that the sealing material can not be inserted between the brick and the brick, resulting in water leakage;
3. The connection of different material interfaces is ignored in the design. If the decorative waist line is designed on the outer wall layer, and the top elevation of the waist line is the same as the top elevation of the ring beam, because the temperature expansion coefficient of the external wall brick and the concrete ring beam is very different, it is easy to produce cracks, which makes the waist line seep water. For the same reason, the root of the parapet wall is often easier to crack and seep water;
4, high-rise building non-load-bearing exterior wall masonry, screed mortar marks, generally lower than the load-bearing wall design marks, strength can meet the design requirements, but increased water permeability;
5, in the design does not pay attention to waterproof, exterior wall facade design without waterproof concept and function Settings.
(2) Prevention and control measures
1. The leakage caused by design factors is mainly controlled in advance;
2. In the review of design drawings, the engineering (supervision) personnel shall review whether there are preventive measures or impermeability and waterproofing requirements in the drawings;
3. Whether the marking of external wall masonry and plastering mortar is appropriate; Whether there are detailed large-scale drawings or anti-seepage requirements for the leaky parts such as flood height, sill slope, olecon, drip tank, and around door and window frames (Figure 3, Figure 4);
4, if there are preventive measures or requirements in the design, the construction must be supervised and implemented; If the design is not put forward or there are improper points, the engineering (supervision) personnel shall put forward suggestions for additions and modifications to the design unit.
2. Leakage caused by material factors
(1) Reason analysis
The quality of the external wall blocks is poor, the quality of waterproof paint, waterproof sealing materials is unqualified, the surface materials are broken, the aluminum alloy doors and Windows are unqualified, and the processing quality is poor, which directly affects the internal quality of the project.
(2) Prevention and control measures
Before construction, the engineering (supervision) personnel shall strictly inspect the external wall materials and components, check the product quality assurance measures for the key main materials such as aluminum alloy materials, adhesive sealing materials, etc., the material inspection certificate, the sample is taken for product quality reinspection, etc., and the unqualified materials are eliminated for engineering.
3. Leakage caused by construction factors
(1) Reason analysis
The exterior wall leakage caused by construction is mainly due to the poor construction quality of the leaky parts, and the main reason for the leakage of the exterior wall is that the construction is not in accordance with the requirements or the monitoring is not in place. The main manifestations are:
1, the frame structure of the external wall column and the masonry joint is not buried or the joint reinforcement is not set firmly, the distance, number and length of the joint reinforcement do not meet the requirements, due to the large difference in temperature expansion coefficient, resulting in joint cracking is a common leakage area;
2, masonry screed layer, plastering layer mortar is not prepared according to the design, resulting in poor mortar strength, dry shrinkage cracking;
3, the external wall tile and the bottom mortar bonding force is insufficient to form a hollow drum, the pointed joint of the decorative brick is not dense, there are sand holes and cracks, resulting in external wall leakage;
4, detailed structure, such as windowsill slope, olecranon, drip tank and other not well treated easy to cause rain penetration;
5, the door and window installation is not carefully waterproof treatment; Improper sealing of pipes and reserved holes through exterior walls.
(2) Prevention and control measures
Before construction, the project (supervision) personnel should check the "External wall leakage prevention construction measures and technical disclosure" formulated by the construction unit, and focus on checking whether the construction process is in line with the regulations. During construction, it is necessary to strengthen process control, strictly supervise the construction of the external wall masonry according to the design requirements and construction specifications, and focus on monitoring the parts of the external wall prone to leakage.
1. Control points of external wall masonry
(1) Masonry corners and junctions shall be laid at the same time; It is strictly forbidden to leave a straight crouching post at the corner of the external wall; When the lower wall of the external window is constructed with porous bricks, cast-in-place concrete slab belt with thickness not less than 60mm should be poured at the sill;
(2) The ash joints of all kinds of masonry should be horizontal and vertical, uniform thickness, the mortar fullness of the horizontal and vertical ash joints shall not be less than 80%, and transparent joints and blind joints shall not appear. Before plastering the exterior wall, it is necessary for a special person to comprehensively inspect the ash joints of the outer wall. For individual blind joints, excavating the width of about 10mm and the depth of about 80mm, removing the garbage and dust in the joints, wetting with water, and caulking mortar;
(3) When the screw holes, feet, hands and eyes of the external wall support die are blocked, cement mortar should be used before plastering to seal tightly to ensure no cracking and no leakage;
(4) The masonry of deformation joints such as expansion joints, settlement joints and seismic joints should ensure the net width of the joints, and should take covering measures or fill polystyrene and other foaming materials to prevent the joints from having blocks, slag, mortar and other debris;
(5) When the strength and stiffness of masonry can not withstand the lateral force generated by the vibration of concrete, reinforcement measures should be taken to prevent the deformation and cracking of masonry and prevent the hidden danger of leakage;
(6) In order to prevent the leakage of the external wall, the awning, open balcony, air conditioner shelf, sunshade, window cover, the root of the external staircase and the decorative molding of the wall should be flooded or take effective measures to stop the water;
(7) In order to prevent leakage of roof parapet walls, materials with large porosity such as porous bricks and hollow bricks should not be used. The external walls of buildings with protruding roofs shall not be constructed with the above materials within the height range of flooding;
(8) Urge the construction unit to make on-site coordination, achieve close cooperation between types of work, so that the masonry construction and the laying of water and electricity embedded pipes in the wall can be coordinated. Avoid the wall twice digging holes and grooving;
(9) The masonry of the filled wall shall adopt a reasonable masonry method. Clear group building method, when the external wall is built to the bottom of the beam, after the wall is fully settled, the inclined brick is sealed and the fullness of the mortar is ensured.
2, external wall plastering control points
(1) Before plastering, clean the base surface, chisel the surface dirt and clean it, and use the polymer cement net slurry to "shake hair" where necessary to enhance the adhesion between the mortar and the base surface;
(2) Strictly control the strength and mixing quality of mortar; The external wall screed plaster layer should be reinforced with metal mesh at the junction of different materials;
(3) Before leveling the plastering construction, the holes left in the external wall construction, the top of the frame filling wall, and the vertical cracks of the hollow brick exterior wall shall be blocked and pointed first, and inspected and accepted as a process, and plastering shall be approved after acceptance;
(4) Before the construction of decorative bricks, it is required that the wall base and surface bricks are wet and dry first, and when pasting decorative bricks on the waterproof layer, it is necessary to sweep the polymer cement paste first. When the exterior wall tile is pointed, it is necessary to clean the joints and wet with water first, the joint mortar should be thick, it is recommended to use polymer cement mortar (flexural strength, toughness, bonding force, not easy to crack), to ensure that the slurry in the gap is dense and full, the joint surface is smooth, no sand holes and cracks; After pointing, water should be poured in time for maintenance;
(5) Strengthen the quality control of the detailed structure treatment, and the inner window sill is about 20mm higher than the outer window sill; The outward slope of the window sill should be ≥20%; Slope of window eaves and beak ≥20%; The width and depth of the drip tank should be ≥10mm (Figure 5); The Angle between the roof gutter and the parapet wall should be R=100mm arc Angle; Roof parapet wall flooding treatment;
(6) The heel of the air conditioning board, the flap window and the wall are smeared into eight figures or sealed with weather resistant sealant; The PVC pipe of the air conditioning pipe is 10mm out of the wall, and the surrounding area is sealed with weather resistant sealant, and the rainwater pipe clip should also be sealed with glue.
(7) The control after the event should be strengthened. The acceptance of the external wall waterproof effect can be obtained by continuous spraying method, that is, by opening a small hole with a diameter of 20 ~ 25mm with a diameter of 2mm@100mm, selecting 30% of the external wall area, and continuously spraying water for 6h at the highest point of the building (the effect is equivalent to 24 consecutive hours)
Article source： Keyword：
1, prevent roof leakage;
2. Prevent basement leakage;
3, prevent kitchen leakage;
4, to prevent external Windows and doors, leakage;
5, prevent water supply and drainage pipes and other parts of leakage.
The reasons for its leakage are mostly caused by the following reasons:
One is: the material is unqualified; The second is: the design node is not detailed; Third, the operator's sense of responsibility is not strong; Fourth, the protection of finished products is not good.
► Leakproof basement
1. Reason analysis
From the current point of view, there are two factors affecting the quality of waterproof engineering, especially underground waterproof engineering, one is the design problem, the other is the construction problem.
The current design of the waterproof project only talks about what materials to use and determine the waterproof grade of the project, and rarely draws the node method and details (refer to the standard atlas). This does not standardize some practices of waterproof engineering from the source;
The second is the problem of construction. After the construction unit, especially the general contractor, undertakes the project, it only finds a qualified waterproof construction unit to subcontract the construction according to the regulations. However, as for how to conduct joint review of drawings in the early stage of the project, the identification of materials and the preparation and review of construction plans according to the specific conditions of the project (including the construction environment and climate, working conditions, the level of underground water level and whether the groundwater has erosion effect, etc.), the main technical links have not been paid as much attention as in the construction of the main project. In the construction, there are few follow-up inspections and side station supervision, so many details are not properly handled, leading to problems on the completion of the project, and serious direct impact on the use of. At this time, the construction unit then spends a lot of manpower and material resources to carry out maintenance (and the effect is often not good), which not only affects the reputation of the construction unit, but also increases the project cost.
2. Prevention and control measures
(1) The underground waterproofing project should follow the principle of multi-channel fortification and balancing hardness and softness; The principle of detailed waterproofing should be carefully constructed.
Self-waterproofing of concrete structure is a kind of waterproofing method which realizes the waterproofing function based on the compactness of engineering structure itself. The underground waterproofing of high-rise buildings basically adopts three fortifications, namely, concrete structure waterproofing (self-defense) + outsourcing flexible waterproofing layer + lime soil auxiliary waterproofing layer. The self-waterproofing of the structure is the key to anti-leakage, which must be strictly monitored and accepted.
1, pay attention to vibration compaction, can not leak vibration;
2. After the concrete pouring is completed, it should be covered with a straw curtain in time and sent for maintenance for not less than 14 days;
3, multi-way fortification, the principle of hardness and tenderness.
At present, the more common practice is to paste waterproof coil or paint waterproof layer on the waterfacing surface of the engineering envelope structure to make a protective layer, and then backfill and do ground waterproof.
(2) Strengthen the waterproof treatment and process control of the detailed structure
The detailed structure mainly includes: construction joints, deformation joints, after pouring belt, embedded bolts, prearranged iron parts, through the wall casing and so on. If these parts are not handled well, it is easy to produce leakage, and the engineering industry has the so-called "ten cracks and nine leaks", and the engineering (supervision) personnel must strictly check the process.
At present, the construction joint, deformation joint, after pouring belt often adopt the practice of water stop, water stop commonly used steel plate water stop and BW rubber water stop effect is better, the operation is relatively simple, but the buried part must meet the design requirements. During the construction of the steel plate water stop belt, attention should be paid to the lap, the weld surface should be welded, and the corner should be strictly treated; A good sealing steel plate should be firmly fixed with the steel bar of the wall (or plate). The steel plate should be straight and not twisted; BW rubber sealing strip immersed in water, expansion rate of 100 ~ 500%, convenient construction, clean the concrete surface, tear off the BW sealing strip isolation paper, use the viscosity of the material itself, stick to the surface of concrete, winter paste force is low or used for vertical stitching, can be separated by 1 meter nail a steel nail, fixed, and then you can pour concrete. The application of BW water seal simplifies the construction process of construction joint, and the water seal performance is reliable.
1. The construction of the buried water stop belt in the deformation joint shall comply with the following provisions
(1) The water stop should be buried accurately, and the hollow ring should coincide with the center line of the deformation joint;
(2) The water stop belt should be fixed firmly, the inner water stop belt of the top and bottom plate should be installed in a "basin shape", and the water stop belt should be fixed with special steel sleeves or flat steel. When flat steel is used for fixing, the end of the water stop strip should be clamped with flat steel first, and the flat steel should be welded with the steel bars in the structure. The spacing of bolts for fixing flat steel should be 500mm;
(3) The middle buried water stop belt is first poured on the concrete side, and its end mold should be firmly supported and strictly prevent leakage;
(4) The joint of the water stop belt should be one place, should be located on the higher position of the side wall, should not be located at the corner of the structure, and the joint should be welded by hot pressure;
(5) The buried water stop belt should use right Angle special accessories at the turning point, and should be made into a circular arc, the corner radius of the rubber water stop belt should be not less than 200mm, the steel edge rubber water stop belt should be not less than 300mm, and the corner radius should be increased with the width of the water stop belt;
(6) It is appropriate to use water expanded rubber ordinary composite rubber strip, water expanded rubber strip with steel wire or fiber fabric in the middle, and hollow ring type water expanded rubber strip. When the water expansion rubber strip is used, effective fixing measures should be taken to prevent the water stop strip from expanding out of the joint.
2. The construction of the post-casting belt shall comply with the following provisions
(1) The pouring time of the post-pouring belt, when there is no design requirement, should be poured after the concrete age on both sides reaches two months, but the post-pouring belt of high-rise buildings should be carried out after the structure is closed;
(2) Before the concrete construction of the post pouring belt, the post pouring belt should be protected if it is an external type water stop belt to prevent mixing debris and damage to the external type water stop belt;
(3) The post-casting belt should be constructed with compensated shrinkage concrete, and its strength grade should not be lower than that of the concrete on both sides;
(4) The curing time of the concrete after pouring shall not be less than 28d.
3. Wall tube (box)
At the place where the pipe passes through the waterproof structure, the casing should be embedded, and the water sealing ring should be welded on the casing, and the welding should be strict. When the number of water sealing rings is installed according to the design requirements, the pipe should first pass through the embedded pipe fitting, and the position should be identified for temporary fixing. Then the casing should be welded firmly with sealing steel plate at one end, and the gap between the casing and the pipe at the other end should be filled tightly with waterproof sealing material. And seal the sealing plate tightly.
(1) Wall bolts:
In order to solve the hidden danger of water seepage left by the wall piercing bolts, disposable waterproof bolts should be used in the basement external wall formwork. The water seal ring shall be made of 4mm thick steel plate with a diameter of 80mm, and shall be soldered firmly with the bolts. After removing the template for the exterior bolts, chisle 40mm deep holes at the roots of the outer bolts, burn the bolts with gas welding, and compact the holes with waterproof mortar.
(2) Detailed structure of wall pipe (box) :
(1) The wall pipe (box) should be embedded before concrete pouring;
② The distance between the wall tube and the inner corner and the concave and convex part should be greater than 25mm;
(3) The pipe through the wall should adopt the casing type waterproof method, and the water sealing ring should be welded outside the casing;
(4) When there are more pipelines through the wall, they should be relatively concentrated and the wall box method should be used. The sealing steel plate of the wall box shall be welded tightly with the embedded Angle steel on the wall, and the modified asphalt flexible sealing material or fine stone concrete shall be injected into the reserved pouring hole on the steel plate for treatment.
(3) Through the wall pipe (box) waterproof construction, through the wall pipe waterproof construction should comply with the following provisions:
① When the casing type wall pipe waterproof structure is used, the wing ring and the casing should be fully welded and dense, and the casing surface should be cleaned before construction;
② The spacing between tubes and tubes should be greater than 300mm;
(3) When the project has protection requirements, in addition to effective waterproof measures, the wall pipe should also take measures to meet the protection requirements (Figure 1, Figure 2).
► Exterior wall is leakproof
Residential engineering external wall leakage phenomenon is more common, rainwater through the external wall cracks into the wall, resulting in the interior wall decorative surface layer mildew, and even cause the paint layer shell, fall off, affect the use of function, serious will cause short circuit wire, resulting in accidents, to the user to bring a certain economic loss and cause disputes, should take effective measures to solve.
1. Leakage caused by design factors
(1) Reason analysis
1, the designer does not pay attention to the details of the large design, such as windowsill slope, eagle mouth, drip tank, through the wall pipe, external wall embedded pipe fittings, aluminum doors and Windows, curtain wall and wall joints;
2, for the sake of beauty, the exterior wall decorative brick (small) is designed into a thin seam splicing, so that the sealing material can not be inserted between the brick and the brick, resulting in water leakage;
3. The connection of different material interfaces is ignored in the design. If the decorative waist line is designed on the outer wall layer, and the top elevation of the waist line is the same as the top elevation of the ring beam, because the temperature expansion coefficient of the external wall brick and the concrete ring beam is very different, it is easy to produce cracks, which makes the waist line seep water. For the same reason, the root of the parapet wall is often easier to crack and seep water;
4, high-rise building non-load-bearing exterior wall masonry, screed mortar marks, generally lower than the load-bearing wall design marks, strength can meet the design requirements, but increased water permeability;
5, in the design does not pay attention to waterproof, exterior wall facade design without waterproof concept and function Settings.
(2) Prevention and control measures
1. The leakage caused by design factors is mainly controlled in advance;
2. In the review of design drawings, the engineering (supervision) personnel shall review whether there are preventive measures or impermeability and waterproofing requirements in the drawings;
3. Whether the marking of external wall masonry and plastering mortar is appropriate; Whether there are detailed large-scale drawings or anti-seepage requirements for the leaky parts such as flood height, sill slope, olecon, drip tank, and around door and window frames (Figure 3, Figure 4);
4, if there are preventive measures or requirements in the design, the construction must be supervised and implemented; If the design is not put forward or there are improper points, the engineering (supervision) personnel shall put forward suggestions for additions and modifications to the design unit.
2. Leakage caused by material factors
(1) Reason analysis
The quality of the external wall blocks is poor, the quality of waterproof paint, waterproof sealing materials is unqualified, the surface materials are broken, the aluminum alloy doors and Windows are unqualified, and the processing quality is poor, which directly affects the internal quality of the project.
(2) Prevention and control measures
Before construction, the engineering (supervision) personnel shall strictly inspect the external wall materials and components, check the product quality assurance measures for the key main materials such as aluminum alloy materials, adhesive sealing materials, etc., the material inspection certificate, the sample is taken for product quality reinspection, etc., and the unqualified materials are eliminated for engineering.
3. Leakage caused by construction factors
(1) Reason analysis
The exterior wall leakage caused by construction is mainly due to the poor construction quality of the leaky parts, and the main reason for the leakage of the exterior wall is that the construction is not in accordance with the requirements or the monitoring is not in place. The main manifestations are:
1, the frame structure of the external wall column and the masonry joint is not buried or the joint reinforcement is not set firmly, the distance, number and length of the joint reinforcement do not meet the requirements, due to the large difference in temperature expansion coefficient, resulting in joint cracking is a common leakage area;
2, masonry screed layer, plastering layer mortar is not prepared according to the design, resulting in poor mortar strength, dry shrinkage cracking;
3, the external wall tile and the bottom mortar bonding force is insufficient to form a hollow drum, the pointed joint of the decorative brick is not dense, there are sand holes and cracks, resulting in external wall leakage;
4, detailed structure, such as windowsill slope, olecranon, drip tank and other not well treated easy to cause rain penetration;
5, the door and window installation is not carefully waterproof treatment; Improper sealing of pipes and reserved holes through exterior walls.
(2) Prevention and control measures
Before construction, the project (supervision) personnel should check the "External wall leakage prevention construction measures and technical disclosure" formulated by the construction unit, and focus on checking whether the construction process is in line with the regulations. During construction, it is necessary to strengthen process control, strictly supervise the construction of the external wall masonry according to the design requirements and construction specifications, and focus on monitoring the parts of the external wall prone to leakage.
1. Control points of external wall masonry
(1) Masonry corners and junctions shall be laid at the same time; It is strictly forbidden to leave a straight crouching post at the corner of the external wall; When the lower wall of the external window is constructed with porous bricks, cast-in-place concrete slab belt with thickness not less than 60mm should be poured at the sill;
(2) The ash joints of all kinds of masonry should be horizontal and vertical, uniform thickness, the mortar fullness of the horizontal and vertical ash joints shall not be less than 80%, and transparent joints and blind joints shall not appear. Before plastering the exterior wall, it is necessary for a special person to comprehensively inspect the ash joints of the outer wall. For individual blind joints, excavating the width of about 10mm and the depth of about 80mm, removing the garbage and dust in the joints, wetting with water, and caulking mortar;
(3) When the screw holes, feet, hands and eyes of the external wall support die are blocked, cement mortar should be used before plastering to seal tightly to ensure no cracking and no leakage;
(4) The masonry of deformation joints such as expansion joints, settlement joints and seismic joints should ensure the net width of the joints, and should take covering measures or fill polystyrene and other foaming materials to prevent the joints from having blocks, slag, mortar and other debris;
(5) When the strength and stiffness of masonry can not withstand the lateral force generated by the vibration of concrete, reinforcement measures should be taken to prevent the deformation and cracking of masonry and prevent the hidden danger of leakage;
(6) In order to prevent the leakage of the external wall, the awning, open balcony, air conditioner shelf, sunshade, window cover, the root of the external staircase and the decorative molding of the wall should be flooded or take effective measures to stop the water;
(7) In order to prevent leakage of roof parapet walls, materials with large porosity such as porous bricks and hollow bricks should not be used. The external walls of buildings with protruding roofs shall not be constructed with the above materials within the height range of flooding;
(8) Urge the construction unit to make on-site coordination, achieve close cooperation between types of work, so that the masonry construction and the laying of water and electricity embedded pipes in the wall can be coordinated. Avoid the wall twice digging holes and grooving;
(9) The masonry of the filled wall shall adopt a reasonable masonry method. Clear group building method, when the external wall is built to the bottom of the beam, after the wall is fully settled, the inclined brick is sealed and the fullness of the mortar is ensured.
2, external wall plastering control points
(1) Before plastering, clean the base surface, chisel the surface dirt and clean it, and use the polymer cement net slurry to "shake hair" where necessary to enhance the adhesion between the mortar and the base surface;
(2) Strictly control the strength and mixing quality of mortar; The external wall screed plaster layer should be reinforced with metal mesh at the junction of different materials;
(3) Before leveling the plastering construction, the holes left in the external wall construction, the top of the frame filling wall, and the vertical cracks of the hollow brick exterior wall shall be blocked and pointed first, and inspected and accepted as a process, and plastering shall be approved after acceptance;
(4) Before the construction of decorative bricks, it is required that the wall base and surface bricks are wet and dry first, and when pasting decorative bricks on the waterproof layer, it is necessary to sweep the polymer cement paste first. When the exterior wall tile is pointed, it is necessary to clean the joints and wet with water first, the joint mortar should be thick, it is recommended to use polymer cement mortar (flexural strength, toughness, bonding force, not easy to crack), to ensure that the slurry in the gap is dense and full, the joint surface is smooth, no sand holes and cracks; After pointing, water should be poured in time for maintenance;
(5) Strengthen the quality control of the detailed structure treatment, and the inner window sill is about 20mm higher than the outer window sill; The outward slope of the window sill should be ≥20%; Slope of window eaves and beak ≥20%; The width and depth of the drip tank should be ≥10mm (Figure 5); The Angle between the roof gutter and the parapet wall should be R=100mm arc Angle; Roof parapet wall flooding treatment;
(6) The heel of the air conditioning board, the flap window and the wall are smeared into eight figures or sealed with weather resistant sealant; The PVC pipe of the air conditioning pipe is 10mm out of the wall, and the surrounding area is sealed with weather resistant sealant, and the rainwater pipe clip should also be sealed with glue.
(7) The control after the event should be strengthened. The acceptance of the external wall waterproof effect can be obtained by continuous spraying method, that is, by opening a small hole with a diameter of 20 ~ 25mm with a diameter of 2mm@100mm, selecting 30% of the external wall area, and continuously spraying water for 6h at the highest point of the building (the effect is equivalent to 24 consecutive hours)
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