The phenomenon of leakage of the external wall of the building occurs from time to time, and once the leakage occurs on the external wall of the building, it often reduces the durability and safety of the building structure, and also affects the decorative effect, durability and use function of the building. The main reason for the leakage of the external wall of the building is due to the existence of void cracks in the concrete, and there are also voids and cracks in the blocks and mortar of the masonryAt the same time, the remaining water inside is squeezed, which also generates compressive stress inside the material, which causes cracks and further expansion of cracks. This paper mainly explains how to take measures to prevent the leakage of building exterior walls from the design and construction aspects.
1. Waterproof and anti-cracking measures should be set up for the exterior wall according to the engineering structure of the exterior wall of the building, the building 2023 turning page materials, the height of the façade, the basic wind pressure and other factors.
2. At the junction of different wall materials and the outer wall with a height of 24m, steel wire mesh or alkali-resistant glass fiber mesh cloth should be laid in the screed layer.
3. When the exterior wall is made of hollow bricks or aerated concrete and other wall materials, the age and strength of the block should meet the requirements of the relevant national specifications, and the metal mesh should be hung in accordance with the requirements of the specifications.
4. The screed cement mortar should be mixed with admixtures such as waterproofing agent, anti-cracking agent, and water reducing agent.
5. Polymer cement mortar should be used for the waterproof layer.
6. The wall supported on the cantilever beam and the cantilever plate should be provided with reinforced concrete anti-crack columns. (as shown below).
7, the exterior wall from the surface of the substrate to the finishing layer should be left lattice joints, the interval should be 3 3m, can be reserved or cut back, metal mesh, leveling layer, waterproof layer, finishing layer should be left in the same position of the seam, the width of the seam should not be greater than 10mm, should not be less than 5mm.
8. When the length of the building exceeds the requirements of the standard joints, special anti-crack measures should be formulated for design and construction. Exterior walls should be painted with high elasticity.
9. Reasonably configure the concrete mix ratio of the exterior wall, and control the amount of cement to 320 380kg m3 to enhance its own crack resistance.
10. The concrete of the masonry wall structural column must be poured densely, the wall is built first and then the column is poured, and the masonry and concrete junction must be hung with a net before plastering.
11. Before the construction of the plastering layer, the base should be cleaned, the wall should be wetted, the slurry should be shaken, and the strength should be maintained after the slurry is completed.
12. When the masonry exterior wall is built, the bottom of the wall should be built with 200mm high cast-in-place concrete reverse ridge or three-skin non-clay solid brick. The tie bar between masonry and concrete wall column must be connected with the concrete reliably, and the anchorage and extension length of the tie bar should meet the requirements of the acceptance specification.
13. The thickness of each layer of plastering of the external wall screed layer shall not be greater than 10mm, and the total thickness of the plastering shall not be greater than 35mm.
14. The lattice joints of the exterior wall should be waterproofed, and the air compressor should be used to blow off the powder in the joints after cutting the joints, and fill with high-elasticity weather-resistant glue.
15. After the construction of the exterior wall is completed, a comprehensive water test should be carried out. The inner diameter of the watering pipeline should be (20 5) mm, the diameter of the watering hole should be 3mm, the spacing should be 180 220mm, the distance from the outer wall should not be greater than 150mm, and the watering pressure should be 03MPa, and should form a uniform water curtain. A watering pipeline is set up every 6 10m, and the continuous watering time should not be less than 30 minutes.