Xinzhou Prefabricated Slab Housing
Xinzhou prefabricated slab housing has typical problems such as old and damaged buildings and roof leakage, which require targeted treatment.
There are a large number of multi-story prefabricated slab-structured residential buildings built in Xinzhou District from the 1990s to the early 2000s. Due to their long history, these buildings generally have safety hazards. For example, the illegal construction at the entrance of Gaochao Community on Financial Street in Yangluo Subdistrict is only built with red bricks for walls and prefabricated slabs for roofing, with unpainted exterior walls. After years of exposure to wind and rain, the building is severely old and damaged, with weeds growing inside the walls and the roof slabs teetering, posing prominent safety hazards.
Roof leakage is another typical problem of Xinzhou prefabricated slab housing. The causes of leakage mainly include: aging and cracking of the roof waterproof layer in old residential areas, and blockage of drainage outlets leading to severe water accumulation during heavy rains; improper overlapping of roofing membranes in newly built high-rise buildings or damage to the waterproof layer caused by later equipment installation, resulting in the formation of water vapor pressure in the insulation layer under high temperatures, causing the waterproof layer to bulge and crack. Leakage points are mostly concentrated at the joints of prefabricated slabs, the roots of smoke exhaust pipes, and the internal and external corners of parapet walls. The hazards of leakage are significant. In mild cases, it can cause mold on indoor ceilings and peeling of wall paint, affecting the living environment; long-term leakage may cause corrosion of the roof structural steel bars, threatening building safety.
The key points of governance require strict control over the construction process and material selection. Before construction, load testing is required. The designed roof load of old buildings with prefabricated slab structures built in Xinzhou in the 1990s is generally 1.5 kN/㎡, and the total weight of construction materials should be controlled within 1 kN/㎡; mark the leakage points, clean up debris on the roof and illegal constructions, and publicize the construction information in advance. In terms of material selection, waterproof materials should use root-resistant SBS modified bitumen membranes to adapt to residents' planting habits; insulation materials should use B1-grade flame-retardant extruded polystyrene boards, which meet fire protection requirements and improve thermal insulation effects. All materials should be provided with inspection reports and pass on-site sampling inspections. During the main construction, for the base treatment, remove the old waterproof layer and insulation layer, wash away the dust with a high-pressure water gun, fill in the gaps in the prefabricated slabs, lay anti-crack mesh fabric and apply mortar leveling for cracks exceeding 2 mm, and make a slope layer; for the insulation layer laying, lay the extruded polystyrene boards in a staggered manner, fill the gaps between the boards with foam glue, apply a cement mortar leveling layer on the surface, and only start the construction of the waterproof layer after it is completely dry (with a moisture content of less than 9%); for the waterproof layer construction, first strengthen the treatment of leakage points, water outlets, and other nodes, and then lay the large-area membrane. To address the problem of easy cracking at the joints of prefabricated slabs, fill with elastic sealing materials and add stress buffer layers to prevent the materials from being pulled apart.
