What are the main causes of cracking in rigid waterproof roofs

The material of cement and coarse and fine aggregates is poor, and the mix ratio and water-cement ratio are poor.

Unsuitable. The main reasons for the leakage of rigid waterproof roofs are: the waterproof standards and fortification requirements are not determined in strict accordance with the national standards according to the category of the building and the reasonable service life of the waterproof layer.

There is no waterproof design principle of "combination of prevention and drainage, rigidity and softness, multiple lines of defense, and joint action", and no attention is paid to drainage design, and reasonable drainage partitions cannot be carried out, and the number of water pipes and rainwater outlets in the bureau is insufficient.

There is no strict operation procedure for roof waterproofing construction.

The construction is carried out, the operation process is wrong, and the construction is not standardized. The material of cement and coarse and fine aggregates is poor, and the mix ratio and water-cement ratio are improper. The concrete is mixed unevenly, and the mixing time is not enough. Concrete pouring can not be carried out continuously, construction joints.

The location of the reservation is unreasonable. Concrete vibrating.

Not compact, leakage, under-vibration or over-vibration.

It is generally caused by thermal expansion and cold contraction! To avoid this problem, when building a house, you should put steel wire mesh to strengthen the tensile resistance! There is also a problem with the construction when building the house!! If the crack is big, it's cutting corners!

The reason for the cracking of the rigid layer of the roof is abnormal, if the roof of the building is cracked, it means that the quality of the project is not good, and another engineering team should be found to renovate it in Tong to prevent the phenomenon of cracking in the building from continuing to aggravate the combustion. The use of blocks as external insulation materials is a relatively advanced form of thermal insulation practices at present. The typical practice is to use polystyrene board composite cement mortar to make composite insulation board, and then fix the insulation board on the exterior wall by sticking and hanging.

This external thermal insulation method protects the concrete shear wall, so that the structural wall will not produce obvious changes in appearance and size due to the change of outdoor temperature. However, the cement mortar surface layer on the surface of the external insulation block will be significantly deformed with the change of temperature every day. After a month at room temperature, especially after the rain washes the new work, the cracks caused by the cracks in the slabs will be clearly displayed.

Thermal insulation technology is an extremely strict and perfect technical system, and any link that cannot meet the requirements will cause cracking consequences. Therefore, each link must be fully matched with the corresponding technology and product bureau.

Summary. Causes of cracks: 1. The bottom is not cleaned with a compartment causing cracking.

2. Natural cracking caused by building subsidence.

3. After the rainy season, there will be cracking when suddenly exposed to the sun.

The most serious problem of rigid waterproof layer roof is that the waterproof layer has cracks after the construction is completed, causing water leakage, and the original cracks.

The reasons for the cracks that will appear: 1. The bottom is not cleaned up and there is a partition to cause cracking, 2. Natural cracking caused by building subsidence 3.

Than the heart] [than the heart].

For the maintenance of cracks in the waterproof layer of rigid waterproof roofs, it is advisable to take corresponding treatment measures according to the crack variation of different parts, and should comply with the following provisions:

1. The seam maintenance of the waterproof layer should be maintained, the polymer modified asphalt waterproof coating or synthetic polymer waterproof coating should be used, and the coating waterproof layer should be paved with carcass reinforcement materials, and the width of the waterproof layer should not be less than 350mm, and its thickness is: polymer modified asphalt waterproof coating should not be less than 3mm; Synthetic polymer waterproof coating should not be less than 2mm. An isolation layer with a width of not less than 100mm should be set along the seam, and the effective bonding width between the periphery of the seam waterproof coating and the concrete of the waterproof layer should not be less than 100mm.

2. The waterproof membrane should be used for joint maintenance, and the original plate joint caulking material that is higher than the board surface and the floating ash or debris on both sides of the plate joint should be cleaned up.

The width of the paving coil should not be less than 300mm, the width of the isolation layer along the seam should not be less than 100mm, the effective bonding width of the surface layer of the seam coil and the waterproof layer of concrete should be greater than 100mm, the lap length of the coil should not be less than 100mm, and the coil should be tightly sealed.

3. The sealing material is used for caulking maintenance, and the seam width should be adjusted to 20 40mm, and the depth is multiple of the width. Before caulking, the embedded material in the crack and the floating ash and debris on the surface of both sides of the joint should be removed, sprayed and coated with a base treatment agent, and after drying, the bottom of the joint groove should be provided with a backing material, and the upper part should be filled as early as a sealing material. The width of the sealing material should exceed the width of the plate seam on both sides and not less than 30mm and slightly higher than the seam, and be firmly sealed with the seam wall.

1. The main reasons for regular transverse cracks are: temperature changes, expansion and contraction of roof panels, and changes in the angle of the end of the slab. In addition, transverse cracks can also occur due to low quality, aging, or cold brittleness under low temperature conditions, reducing its toughness and elongation.

2. The reasons for irregular cracks are: the lap joint of the coil is too small, the joint cracks and warps after the coil shrinks, the coil is aging and cracked, the bubble is ruptured or traumatized, etc. In addition, improper setting or poor treatment of the lattice joints of the leveling layer, as well as irregular cracking of cement mortar, etc., will also cause irregular cracking of the coil.

For the irregular crack zone cracks (except for aging cracks) that have not cracked in the base layer, the coil can generally be subsidized at the cracked place. Within a few years after the completion of the roof, regular transverse cracks are in the stage of occurrence and development, and only the treatment of the year can be effective.

Regular cracks mainly occur on prefabricated roofs. The main reason for regular cracks is the stress change of the roof panel end caused by the stress of the roof structure and the change of temperature, which leads to the cracking of the waterproof layer. The methods for dealing with regular cracks are:

1) Remove the protective layer at the crack, clean up the floating ash debris in the crack and on both sides, spray the base treatment agent, embed the sealing material in the joint, slightly higher than the waterproof layer, and lay the membrane isolation layer with a width of not less than 100mm on the seam or unilaterally stick, and then pave the membrane with a width greater than 300mm.

2) Use elastic sealing materials to repair cracks to adapt to the deformation of the base layer and prevent cracking. First, remove the rigid waterproof layer in the range of 50mm, cut the groove into a groove with a width of 20 40mm and a depth of times the width along the seam, clean the floating ash residue in the groove, and then spray the base treatment agent, embed the backing material, and fill the sealing material in the seam and exceed the two sides of the seam not less than 30mm, and the plane is not less than 3mm, and the surface is arc-shaped.

3) When using waterproof coating to repair cracks, after cleaning the surface of the floating ash debris along the cracks, first set up an isolation layer with a width of 100mm between the cracks and the coating film, and then lay two layers of coating film waterproof layer with carcass reinforcement, the width is 300mm, and the seams are painted with paint many times to form a certain thickness seal.

2. Treatment of irregular cracks.

Irregular cracks are characterized by different lengths, uncertain directions, and uneven density. The treatment method is: remove the crack and its surrounding protective layer, clean up the floating ash and debris on the surface layer of the crack part, and pave the membrane with a width of 250mm or the coating film waterproof layer with carcass reinforcement material along the crack, and fill it with adhesive and solid sealing.

When encountering a crack area where multiple cracks are concentrated together, remove the protective layer, the range is slightly larger than the crack area, remove the floating ash, apply the base treatment agent, and then pave the waterproof membrane or the coating film waterproof layer with the reinforced carcass.

3. Treatment of large-area cracks.

For the location of large areas of aging cracks, all the aging cracks are removed until they are surrounded by a good waterproof layer, the base treatment agent is painted, the new membrane waterproof layer is paved, and the old waterproof layer is closely overlapped.

4. Treatment of cracking of gutters, eaves, flooding and other parts.

The crack is filled with sealing material, and an additional layer of coil or a coating film with carcass reinforcement material is laid on the seam. The paved coil should be sealed tightly.

5. Treatment of cracking of the connection between the roof structure and the base layer such as parapet walls and gables

Clean the cracks, fill the seams with sealing materials, lay a membrane or a coating film waterproof layer with carcass reinforcement material on it, and press it under the façade membrane to seal the lap joints.

6. Treatment of circumferential cracks in the roof pipes or embedded parts

Remove the surrounding and sealing materials of the pipeline or embedded parts, cut the groove between the pipeline and the embedded parts and the leveling layer, and renovate the leveling layer, the groove is filled with sealing materials, add an additional layer, add a layer of coil or coating film with carcass reinforcement materials, tie it firmly with metal hoops or wires, and seal it tightly with sealing materials.

2.Construction requirements.

The thickness of the waterproof layer of fine stone concrete should not be less than 40mm, and should be equipped with two-way reinforcement mesh. The sub-grid of the steel mesh sheet.

The seam should be disconnected, and its protective thickness should not be less than lomm.

3.Material and mix ratio requirements.

Material requirements: fine stone concrete shall not use pozzolana cement; When Portland cement is used, minus should be used.

Measures to reduce water secretion. The mud content of coarse aggregate should not be greater than l%, and the mud content of fine aggregate should not be greater than 2%.

Mix ratio requirements: concrete water-cement ratio should not be greater than; The amount of cement per cubic meter of concrete shall not be less than.

330k9;The sand content should be 35% 40%; The sand-cement ratio should be 1:2 1:, and the concrete strength grade should not be lower than C20.

4.Other requirements.

Isolation layer: An isolation layer should be set between the waterproof layer and the base layer. The isolation layer can be paper ash or hemp gray, low strength, etc.

grade mortar, dry-laid coil, etc. When the compensating shrinkage concrete is used as the waterproof layer, the isolation layer can not be made.

Grid joint: The waterproof layer must be divided into grids, and the grid joints should be set at the supporting end and roof rotation of the prefabricated structure roof panel.

The junction of the fold, the waterproof layer and the roof protruding structure should be aligned with the plate joint, and the longitudinal and horizontal spacing should not be large.

at 6m. The lattice seam should be embedded with ointment. The ridge and the lattice seam parallel to the direction of the flowing water can also be made into flooding.

The cover tile is covered, and the cover tile should be fixed unilaterally.

Flooding: Roof flooding and roof waterproofing must be made at one time, and the flooding height should not be less than 12ram.

5.Construction requirements for fine stone concrete rigid roof waterproofing project.

The waterproof layer of fine stone concrete shall not have leakage or water accumulation. (Mandatory Provisions).

Fine stone concrete and compensating shrinkage concrete waterproof layer, the construction temperature should be 5, not at a negative temperature and.

Construction under the scorching sun.

After pouring, it should be cured in time to keep it moist, and the curing time should not be less than 14d.

Fine stone concrete should be made of ordinary Portland cement with strength grade and above, every im. Minimal cement.

Dosage 330k9. The maximum grain of coarse aggregate is -j"l5mm, and the mud content should not be greater than l%. Fine aggregates should be made of medium sand.

or coarse sand, the mud content should not be greater than 2%.

The water-cement ratio should not be greater than.

The steel mesh in the waterproof layer of fine stone concrete should be set in the center of the waterproof layer.

The pouring of concrete should be carried out in the order of "first far and then near, first high and then low", and each grid plate.

After the pouring is completed at one time, it is strictly forbidden to leave construction joints.

During construction, mechanical vibration is used to compact, the surface is smoothed after slurry, and the water should be compacted and wiped again after collecting water (no water is allowed.

mud or add cement slurry).

Use alkali-resistant fiberglass mesh cloth and apply it with flexible waterproof putty for reference.

I don't know if the cost is low or not, hehe, more information, better advice, free professional technical advice on concrete waterproof leakage repair, exempt from repairing today and leaking tomorrow; Repair every year, the trouble of leaking every year.