Prefabricated buildings offer potential benefits, but not all advantages are practical or feasible. Any new technology requires thorough studies of both its feasibility and limitations. Focusing solely on feasibility risks overlooking critical drawbacks.
Currently, some local governments strongly promote prefabricated buildings by mandating specific assembly and prefabrication rates within their jurisdictions. However, this approach overlooks the importance of adapting to local conditions and allowing market forces to guide development, which is the most effective strategy.
If a technology or process does not improve productivity, lacks cost advantages, or even raises costs significantly—while failing to guarantee quality—it has no real value for promotion. The construction industry must transform and upgrade its methods, but such changes must be practically feasible.
Some claim that prefabricated buildings reduce labor by 30% to 50% compared to traditional cast-in-place construction, suggesting a clear labor advantage. However, the total labor demand remains the same or may even increase. Labor shifts from on-site tasks like steel reinforcement, formwork carpentry, and concrete pouring to off-site prefabrication plants. Additionally, new labor is required for on-site installation of prefabricated components, which was not needed before.
Others argue that prefabricated buildings shorten construction time. While factory-based component production can occur simultaneously with site preparation, installing prefabricated components often requires more labor hours. Field studies indicate that prefabricated buildings may demand more labor and take longer to complete than cast-in-place structures. When the prefabrication plant’s capacity is insufficient, construction sites might face delays, which can postpone the entire project.
Some analyses highlight that prefabricated buildings reduce water, electricity, and formwork waste by 20% to 40%, emphasizing their environmental benefits. The main advantage lies in reducing on-site wet work, but actual savings in water and electricity are not guaranteed.
After extensive research, the author concludes that prefabricated buildings offer limited advantages over traditional cast-in-place methods. The success of prefabrication overseas is largely due to more mature technology and standardized components.
The following factors currently limit the development of prefabricated construction in China:
- Immature Technology and Lack of Skilled Operators: Both domestic and foreign prefabrication technologies are still developing, and skilled workers are scarce.
- Lack of Standardization: Domestic building components lack uniform standards and specifications frequently change, resulting in customized production rather than mass manufacturing. This leads to low reuse rates and prevents economies of scale.
- Inadequate Craftsmanship: Migrant workers accustomed to rough construction struggle to meet the precision required for prefabricated buildings.
- Quality Risks in Assembly: Prefabricated buildings have numerous joints that can cause water seepage, especially if workmanship is poor. While cast-in-place structures may also suffer from water issues, they remain monolithic. Improperly sealed joints in prefabricated buildings can lead to costly repairs within a few years and negatively affect structural integrity.
- High Costs and Space Requirements for Prefabrication Plants: The need for diverse molds, curing time, and on-site storage demands significant factory space. In expensive urban areas, land costs for prefabrication plants are high, while remote plants increase transportation expenses.
- Transportation and Installation Challenges: Moving and hoisting large prefabricated components incurs high costs and safety risks.
- Structural and Seismic Limitations: Prefabricated buildings generally have inferior seismic performance compared to cast-in-place structures. This restricts the use of prefabricated components in high-rise and underground buildings. In mixed structures, cast-in-place walls require an amplification factor of at least 1.1 for seismic forces, and overall seismic design demands are higher, increasing costs.
- Higher Tax Burden: Prefabricated components are subject to a 17% value-added tax, compared to just 3% for concrete in cast-in-place structures. This tax difference raises costs for construction companies.
If a technology offers no cost advantage and compromises quality, rational economic actors have little incentive to adopt it, except under special circumstances.
Why do governments enforce prefabrication mandates? Often, it is motivated by goals such as environmental protection, energy conservation, and green building initiatives. It may also aim to support existing prefabrication manufacturers facing insufficient production capacity. However, large-scale adoption can overwhelm factories, causing component prices to soar and frustrating developers—undermining the intended benefits.
For example, Zhongnan Construction has long engaged in prefabricated construction. Although its costs exceed those of cast-in-place buildings, housing prices are lower due to significantly inferior quality.
Some studies undertake quantitative cost analyses of prefabricated buildings, which is a necessary foundation. Yet, due to numerous complex and variable factors, these analyses often lack practical guidance. A broader, macro-level perspective is essential to truly understand the issue. Sometimes, a few well-chosen words can clarify matters more effectively than lengthy reports.
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