Common Quality Problems and Treatments of EPS Lines on Exterior Walls

As a practical work with high practical requirements, the treatment of the quality of EPS lines on exterior walls has its own particularity. The research on this topic will better enhance the analysis and control of the common quality problems of EPS lines on external walls, so as to further optimize the final overall effect of its governance work through rationalized measures and approaches.
 
External wall EPS external insulation construction overcomes the problem of "sandwich wall" and internal insulation local "cold bridge", prevents condensation inside the wall, protects the main structure, enhances thermal insulation effect, increases the use area, improves the original external wall sandwich method and The common quality problems caused by the internal insulation construction will not affect the insulation effect due to the user's decoration. This paper introduces the construction quality problems, improvement measures and quality management of EPS external insulation on the exterior walls of residential buildings.
 
For the exterior walls of energy-saving buildings, the method commonly used at present is EPS external insulation construction technology, and its basic structure from inside to outside is: wall, polymer glue, EPS polystyrene board, polymer glue, alkali-resistant glass fiber mesh Gingham, polymer glue, paint. It can be sticky or full sticky when sticking. When sticking flowers, the grouting area should not be less than 30%, the edge point should be 25mm from the edge of the benzene board, the diameter of the glue point should not be less than 80mm, and the thickness should be 2mm. At the same time, it is necessary to pay attention to the staggered joints of the upper and lower plates, the corners of the walls must be bitten and dislocated, and large-area construction must leave grid joints and deformation joints. When paving the glass fiber mesh cloth on the polystyrene board, it must be fully paved, and the lap width is 70mm to 100mm. The pasted alkali-resistant glass fiber mesh cloth should be flat, without wrinkles, delamination and glue leakage. Fiber-reinforced layers can be added to easily damaged parts such as windowsills and door and window openings. The final exterior surface can choose paint, face brick, etc. according to different needs and design requirements.
 

Discussion on Common Quality Problems and Treatment Measures of EPS Lines on Exterior Walls

1 crack in the wall

(1) Causes
① Directly use cement mortar as the anti-crack protection layer: high strength, large shrinkage, insufficient flexibility and deformation, causing cracking of the mortar layer;
② Insufficient air permeability of the anti-crack protective layer, such as the application of extruded polystyrene board on the concrete surface;
③Although the prepared anti-cracking mortar is also modified with polymers, the flexibility is not enough or the anti-cracking mortar layer is too thick: the content of organic substances in the adhesive is too high, and the anti-aging ability of the mortar is reduced.
④ Low temperature causes brittle fracture of the network membrane structure after the polymer emulsion in the binder is cured, and loses its own flexibility;
⑤ The particle size of the sand is too fine, the mud content is too high, and the particle gradation of the sand is unreasonable;
⑥The density of benzene board is too low, and the dimensional stability is unqualified; The four corners are not overlapped.
⑦ Unqualified glass fiber mesh cloth is used, such as: low crack resistance, low retention rate of alkali resistance strength, large fracture strain, etc.; the square meter weight of glass fiber mesh cloth (or galvanized steel wire mesh) is too low, The elongation is too large, the mesh size is too large or too small, the coating amount of the alkali-resistant coating layer of the mesh cloth is insufficient, or the thickness of the galvanized layer of the steel wire mesh is insufficient, and the steel wire is corroded and expanded.
⑧The embedding position of the mesh cloth in the surface layer is improper, too close to the inner side; there is no overlap between the mesh cloth or the size of the lap joint cannot meet the requirements of the specification; Set up reinforced grid cloth; lay the grid cloth on the wall directly when wiping the bottom mortar, the mortar and the grid cloth cannot be well combined as a whole, so that the grid cloth cannot play the proper restraint and dispersion effect .
⑨ The surface of the insulation board is uneven, especially the surface of the adjacent board is uneven. The gap between the boards is filled with adhesive; rigid putty is used, but the putty is not flexible enough; water-resistant putty is used, and it will bubble and crack after being soaked in water; the coating with hard film film has a small elongation at break; putty and coating Mismatch. For example, some solvent-based paints are used on polymer-modified putty, because the solvent in the paint will also dissolve the polymer in the putty, which will destroy the performance of the putty; Deformation joints of the thermal insulation system; improper waterproofing treatment schemes at the cut-off parts of the thermal insulation system due to the change of different materials; the construction of the surface layer is carried out under the sun exposure or the surface layer is not sprayed in time after the surface layer is wiped in high temperature weather. The surface layer loses water too quickly; the construction is under low temperature in winter, the antifreeze measures are not in place, and the deformation is caused by frost heaving; the construction technical regulations are violated, and the window frame is not installed before the insulation or the window is wiped after the insulation.

(2) Technical measures to be taken to overcome cracks in wall insulation engineering
The anti-crack problem of the anti-crack protective layer is the main contradiction. It is necessary to use a special anti-crack mortar supplemented by a reasonable reinforcement net. Adding an appropriate amount of polymer and fiber to the mortar is effective in controlling the occurrence of cracks. The anti-crack protective layer composed of plastering mortar and reinforced mesh plays a key role in the anti-crack performance of the whole system. The ultimate tensile deformation of the plastering mortar should be greater than the sum of its own deformation (dry shrinkage deformation, chemical deformation, humidity deformation, temperature deformation) and base deformation under the most unfavorable conditions, so as to ensure the crack resistance requirements of the anti-crack protective layer. The use of reinforced mesh (such as glass fiber mesh cloth) compounded in the plastering mortar can effectively increase the tensile strength of the anti-crack protective layer on the one hand, and on the other hand, because it can effectively disperse the stress, the wider Cracks (harmful cracks) are dispersed into many finer cracks (harmless cracks) to form their anti-cracking effect. The material and amount of plastic coating on the surface are of great significance to the early alkali resistance of glass fiber mesh, and the variety of glass fiber has decisive significance for long-term alkali resistance.

2 There is an empty drum on the surface layer

The installation of plaques, neon lights, advertisements, etc. on the completed surface layer destroyed the protective layer. In winter, snow water poured into the cracks of the insulation board, and the cycle of freezing and thawing caused hollowing or deformation. Therefore, when installing other accessories on the completed surface layer, the protective layer must be protected, and practical measures must be taken to protect the coat of the building.
 
The moisture content of the grass-roots plaster, insulation layer, and protective layer is high, and the air-tight exterior wall paint should be applied immediately. The high temperature in summer or high indoor temperature in winter and poor ventilation will prevent the water vapor from the wall from being discharged, causing some water vapor to concentrate in a certain part, resulting in hollowing of the surface layer. Therefore, when brushing paint, especially when painting airtight paint, the moisture content of the base layer shall be in accordance with the requirements of GB50210 (10) Coating Engineering Article 10.1.5: when the concrete or plaster base layer is painted with solvent paint, the moisture content shall not exceed 8 %, when applying emulsion paint, the moisture content shall not exceed 10%. For the construction projects of that year, it is best to paint the exterior wall paint in the second year to ensure the project quality of the unit project.
 
To sum up, it is of great significance to strengthen the research and analysis of the quality problems and treatment of EPS lines on exterior walls for the achievement of good practical effects. Therefore, in the application process of EPS lines on exterior walls in the future, it is necessary to strengthen the relationship between key links and The degree of emphasis on key elements, and the scientific nature of their specific implementation measures and methods.