Old Prefabricated Concrete Houses

Old prefabricated concrete houses typically refer to prefabricated panel houses, also known as prefabricated concrete panel houses, which emerged as 'industrial houses' to meet the demand for rapid housing construction.

Construction Methods and Historical Development

Prefabricated panel houses are constructed using a factory-prefabricated, on-site assembly model. The main structural components, such as wall panels, floor slabs, beams, and columns, are formed in factories and then transported to the site for assembly using cranes. Originating in the early 20th century, they were initially used for floor slabs and roof insulation layers. In China, most residential buildings constructed before 1985 adopted this structural form. During the 1970s and 1980s, to alleviate urban housing shortages, prefabricated panel houses were widely used due to their short construction periods and moderate costs. With advancements in building technology, cast-in-place concrete and prefabricated buildings have gradually replaced traditional prefabricated panel houses.

Advantages and Disadvantages Analysis

Advantages:

• Short Construction Period: Traditional brick-and-mortar houses require 2-3 years, while prefabricated houses can be completed in just a few months, making them suitable for scenarios requiring urgent completion.
• Cost Control: Moderate construction costs offer high cost-effectiveness.

Disadvantages:

• Low Structural Strength: Overall seismic resistance is weak, and prefabricated panels without rigid steel connections are prone to cracking and water leakage.
• Insufficient Durability: The design life is approximately 40 years, with existing houses having a lifespan of about 30-50 years.
• Poor Sound Insulation: The assembled structure results in subpar sound insulation performance.

Policy and Market Dynamics

Policy Orientation:

• Demolition and Renovation in Parallel: The Ministry of Housing and Urban-Rural Development has mandated that prefabricated houses that have 'exceeded their service life' or pose safety hazards must be demolished, while those without hazards should be upgraded through measures such as repairing utilities, reinforcing structures, and installing elevators. Since 2022, the renovation policy has focused primarily on repairs, with demolitions limited to dangerous buildings.
• Priority Demolition Types:
  • Dangerous Buildings: Those identified as Grade D (severely dangerous) by professional institutions or those failing to meet seismic resistance standards.
  • Buildings Conflicting with Urban Planning: Houses requiring land evacuation for subway construction, school building projects, etc.

Market Situation:

• Brands and Materials: Brands such as Xinwei Hongtu and Yongchang are available on the market, with materials including concrete and color-coated steel. Styles range from modern minimalist to light steel mobile houses.
• Technological Upgrades: In rural areas of Henan, fully reinforced concrete prefabricated houses have emerged, priced at approximately 300 yuan per square meter. These houses can be built into villas in just 4 hours, with a lifespan of 70 years and significantly improved parameters such as snow load resistance and bearing capacity.

Conclusion

Old prefabricated concrete houses were once a key solution for rapidly addressing housing shortages. However, due to limitations in structural strength and durability, they are gradually being replaced by modern building technologies. Current policies prioritize safety, balancing urban renewal needs through the demolition of dangerous buildings and the renovation of old houses. Meanwhile, technologically upgraded new prefabricated houses demonstrate longer service lives and stronger adaptability.