Cracks in Prefabricated Panel-Spliced Houses

The causes of cracks in prefabricated panel-spliced houses are diverse, and the risks vary significantly. Safety assessment requires a comprehensive consideration of crack characteristics and the overall condition of the house.

1. Surface Plaster and Temperature Stress Cracks
   The joints between prefabricated panels are inherently weak interfaces. Surface plaster and joint mortar, due to their material shrinkage properties and differences in thermal expansion and contraction among various materials, are prone to forming surface cracks at the splicing locations under long-term temperature changes. These cracks exist only in the decorative surface layer and do not damage the main structure of the prefabricated panels. They generally have no significant impact on floor safety but require attention to waterproofing to prevent leakage.

2. Long-Term Vibration-Induced Cracks
   Long-term minor loads, such as vibrations from surrounding traffic, renovation construction disturbances, or indoor equipment vibrations, continuously act on the joints of the prefabricated panels, causing the surface gaps to loosen and form continuous straight cracks. These cracks are commonly found in houses located in busy traffic areas or with frequent equipment vibrations. Although they do not directly threaten structural safety, it is necessary to monitor their expansion and reinforce the joint connections if necessary.

3. Cracks Due to Aging of Panel Joint Structures
   The joints between prefabricated panels rely on filler materials to form a cohesive load-bearing system. Over long-term use, the filler layer ages, weakening the overall integrity and reducing the restraint between panels, leading to the formation of regular through cracks. These cracks indicate a degradation in the structural integrity and require a focus on checking whether the filler material has fallen off or if the joints have become misaligned. If the crack width continues to increase or is accompanied by abnormal sounds, structural reinforcement should be carried out promptly.

4. Cracks Due to Uneven Local Loads
   Long-term stacking of heavy objects indoors or on the roof can cause excessive local loads, leading to deflection and deformation of the prefabricated panels. The inconsistent deformation between adjacent panels generates tensile forces, resulting in straight cracks along the panel joint interfaces. If the loads persist, the cracks may develop slowly. It is necessary to assess whether the load distribution is reasonable and, if necessary, adjust the position of the heavy objects or add supports.

5. Cracks Due to Support Settlement or Beam Deformation
   Bending of the lower load-bearing beams or uneven settlement of the foundation can cause inconsistent deformation of the prefabricated panel supports, leading to relative misalignment and stretching of the panels and the formation of straight through cracks at the weak panel joints. These cracks require focused observation and monitoring. If accompanied by wall tilting, window and door deformation, or ground settlement, they may endanger the overall safety of the house, and a professional institution should be immediately commissioned to conduct a risk assessment.

Professional Assessment Recommendations: The risk assessment of a house should consider the location, length, depth, direction, quantity, and development of cracks, as well as the condition of load-bearing walls, beams, panels, columns, foundations, and component connections. Upon discovering cracks, self-repair and concealment should be avoided, and a structural engineer should be contacted promptly for an on-site assessment.