The Use of Prefabricated Panels in House Construction

The use of prefabricated panels in house construction was a common practice in the early 20th century. Below are the core principles, types, application scenarios, and modern alternatives of prefabricated panels:

Core Manufacturing Principles of Prefabricated Panels

Prefabricated panels are concrete components produced through standardized processes in prefabrication yards. During manufacturing, a hollow mold is first made using wooden planks. After arranging steel bars in the hollow part of the mold, cement is poured and allowed to solidify. Once dry, the wooden planks are knocked off, forming a concrete panel with a steel bar framework. This process ensures uniform component dimensions and controllable quality through factory production, while also reducing the amount of wet work on-site.

Types and Structural Advantages of Prefabricated Panels

Prefabricated panels come in two types: solid and hollow. The hollow structure reduces concrete usage by reserving holes in non-load-bearing areas, achieving a lightweight design. Their core advantages include:

• Reduced Weight: The hollow part does not bear loads, and pouring concrete there serves no practical purpose. Leaving it hollow reduces the component's self-weight, facilitating transportation and installation.
• Cost Savings: Reducing concrete usage directly lowers material costs, while also shortening the construction period, resulting in lower overall costs.

Typical Application Scenarios of Prefabricated Panels

1. Floor Panels and Roof Insulation Layers: Prefabricated panels can serve as load-bearing components between floors or enhance roof insulation by filling the hollow structure with insulating materials.
2. Infrastructure Coverings: For example, covers for ditches beside highways utilize the standardized dimensions and load-bearing capacity of prefabricated panels for quick covering and maintenance.
3. Damp-proofing in Rural Self-built Houses: By constructing an elevated layer of prefabricated panels on the ground ring beam, the principle of "trading space for dryness" is applied to block the rise of underground moisture, effectively solving the problem of damp floors on the ground floor.

Modern Construction Techniques Replacing Prefabricated Panels

With technological advancements, cast-in-place concrete and prefabricated buildings are gradually replacing traditional prefabricated panel houses:

• Cast-in-place Concrete: Formed through on-site formwork and pouring, it enhances structural integrity but has a longer construction period.
• Prefabricated Buildings: Utilizing factory-prefabricated modules (such as CMC composite modules), they enhance earthquake resistance through steel-concrete integrated pouring, with a construction period 30% shorter than traditional methods.

Limitations of Existing Prefabricated Panel Houses

Existing prefabricated panel houses generally have the following issues:

• Weak Earthquake Resistance: The connection nodes between components are prone to loosening, making them susceptible to overall collapse during earthquakes.
• Poor Sound and Heat Insulation: Hollow structures or single-layer concrete make it difficult to effectively block sound and heat transfer.
• Limited Service Life: Approximately 30-50 years, far shorter than the over 70-year lifespan of cast-in-place concrete structures.

Policy Orientation and Renovation Directions

Since 2022, China has implemented renovation policies focusing on repairing and renovating prefabricated panel houses, with only those meeting hazardous building standards being demolished. Renovation priorities include reinforcing structures, adding insulation layers, and updating pipelines to extend the building's service life and enhance living safety.