Over 30-Year-Old Prefabricated Panel Houses

Over 30-year-old prefabricated panel houses do not necessarily have to be demolished; there are clear regulations and procedures for their design lifespan, renovation, reconstruction, and maintenance.

I. Misconceptions about Design Lifespan: 50 Years as the Standard, 30 Years Not Mandatory for Scrapping

The state has never mandated a "30-year mandatory scrapping" for prefabricated panel residential buildings. According to the Unified Standard for Reliability Design of Building Structures (GB50068-2018), the design service life for ordinary buildings is 50 years, and this standard also applies to prefabricated panel buildings.

• Origin of the "30-year lifespan": In the 1970s and 1980s, some temporary factory buildings and simple auxiliary buildings referred to a 30-year inspection cycle. This was later miscommunicated, leading to the confusion between the lifespan of simple buildings and residential buildings.
• Design service life ≠ mandatory scrapping lifespan: The 50-year period refers to the expected safe service life of the building under normal construction, material compliance, and regular maintenance. In the past, some standards used a 30-year design reference period (for calculating loads such as wind, snow, and earthquakes), but the current standard has been unified to 50 years, and the design reference period is unrelated to the actual service life.

II. Conditions for Renovation and Reconstruction: Must Comply with Policies and Follow Procedures

If the building is located within an urban planning area, holds a legal property certificate, belongs to a non-single-property-right community, and has been identified as a Grade D dilapidated building or has no repair value, it can apply for in-situ demolition and reconstruction according to procedures:

1. Owner Decision-Making: Owners must voluntarily establish a self-renewal committee or entrust an implementation entity, and obtain approval from a statutory proportion of owners through voting.
2. Application Process: Submit an application to the local township government, which will jointly assess feasibility with multiple departments, prepare a renovation plan, and handle relevant permits.
3. Costs and Policies: Renovation costs are shared by property owners. Eligible projects can apply for superior-level subsidies; property owners and their spouses can withdraw housing provident fund to cover personal contributions, while enjoying reductions in administrative fees, lower limits on service charges, and preferential land prices.

III. Reinforcement and Renovation Process: Requires Professional Assessment and Precise Construction

Taking the Chongming Zhongxing Town project as an example, a comprehensive structural safety assessment must be conducted before renovation, focusing on:

• Prefabricated panel cracks: Special treatment is required for cracks wider than 0.3 millimeters.
• Connection status: Bolts connecting prefabricated panels to ring beams with a rust rate exceeding 30% must be replaced.
  The construction phase includes: removing wooden roofs, pouring concrete roofs, repainting exterior walls and grouting reinforcement; erecting temporary support systems (setting steel pipe supports every 1.2 meters along the length of the prefabricated panels); implanting steel bars into panel joints and pouring fine aggregate concrete; adding structural columns at the four corners of the building (with a cross-section of 240*240 millimeters, reinforced with steel bars and connected to the floor slab).

IV. Waterproofing Issues: Must Strictly Adhere to Process Standards

The joints between prefabricated panel floors are natural "water leakage channels," and waterproofing must ensure:

• Kitchen, bathroom, and balcony walls: Waterproofing height must meet standards, with full coverage in shower areas.
• Bathroom backfill layer: Reserve a waterproof inspection port and ensure proper secondary drainage to prevent water accumulation from seeping into panel joints, causing wall leakage and mold.