Vertical Cracks in the Walls of Prefabricated Panel Houses

Vertical cracks in the walls of prefabricated panel houses require comprehensive treatment based on crack characteristics, house condition, and policy background, as detailed below:

1. Crack Treatment Techniques

For fine and stable cracks (typically less than 0.3mm in width), a 'filling + reinforcement' approach can be adopted during renovation: first, fill the gaps with elastic filling materials (such as epoxy resin or acrylic sealant), then reinforce the surface with Dacron fabric or fiberglass mesh for enhanced crack resistance. If the cracks are located in load-bearing structures or pose a risk of progression, carbon fiber sheets can be applied to improve structural stability. It is important to note that crack width is not the sole criterion for assessment; factors such as location (e.g., proximity to doors, windows, or beam-column joints), orientation (e.g., 45-degree diagonal cracks), depth (e.g., whether they penetrate the wall), and progression (e.g., continuous widening or water seepage) must also be considered for a comprehensive safety evaluation.

2. Safety Risk Warnings

If cracks are accompanied by the following phenomena, it may indicate structural damage to the house:

• Dynamic Crack Changes: Continuous widening, lengthening, or the appearance of new cracks;
• Structural Deformation: Doors or windows getting stuck and unable to open or close normally, floor sagging or tilting, concrete spalling;
• Load-Bearing Anomalies: Diagonal cracks in walls (especially load-bearing walls), horizontal fractures in floors.
  According to the 'Standard for Dangerous House Appraisal' JGJ 125-2016, such situations require immediate professional appraisal, potentially involving Class C (partially dangerous, requiring reinforcement) or Class D (overall dangerous, requiring demolition and reconstruction) houses.

3. Policies and Responsibility Attribution

• During Warranty Period: If the house is still within the warranty period (the warranty period for the main structure is typically the design's reasonable service life, far exceeding 40 years), the construction unit is responsible for repairs;
• After Warranty Period: Owners are responsible for repairing private parts (such as indoor walls); for public areas (such as exterior walls, stairwells), applications can be made to use maintenance funds;
• Governance and Renovation Initiatives: The 2025 central document proposes the implementation of governance and renovation for urban prefabricated panel houses. The '15th Five-Year Plan for Urban Renewal' in 2026 specifies the establishment of files and dynamic updates for Class C and D dangerous houses, as well as the promotion of renovations. Owners should stay informed about local policy developments.

4. Long-Term Risks and Prevention

Prefabricated panel houses, due to their low structural strength, poor earthquake resistance, and short service life (possibly only 20-30 years), may experience worsening wall cracks over time. Regular monitoring of crack changes is necessary to avoid overloading during renovation (such as removing load-bearing walls or adding floors); if cracks are caused by wall water seepage or steel reinforcement corrosion, waterproofing issues must be addressed simultaneously (such as redoing exterior wall waterproofing layers or applying anti-corrosion coatings) to prevent recurring problems from mere surface repairs.

Recommendation: Immediately observe whether cracks continue to progress; if there are structural risks, contact a professional appraisal agency as soon as possible; refer to policy developments and stay informed about local dangerous house renovation plans; prioritize addressing root causes such as water seepage and steel reinforcement corrosion during repairs.