What is a Prefabricated Panel in a House

A prefabricated panel is a module or slab used in engineering, referring to a pre-fabricated concrete component produced and processed in a factory in advance. It is made by nailing a wooden model, arranging steel bars, and pouring cement, and is divided into two types: solid and hollow.

Structure and Types

The core structure of a prefabricated panel consists of a steel bar framework and concrete. During production, a wooden model is first nailed to define the shape, steel bars are arranged inside to enhance load-bearing capacity, and then cement is poured to solidify the form. Based on differences in internal structure, there are two types: solid and hollow:

• Solid prefabricated panels: These have solid concrete inside, offering high overall strength but are relatively heavy, often used in scenarios with high load-bearing requirements.
• Hollow prefabricated panels: These reduce non-load-bearing concrete by pre-forming holes inside, achieving lightweight construction while lowering material costs. They are commonly used in non-critical load-bearing parts such as floor slabs.

History and Application

Prefabricated panels originated in the early 20th century and were initially used in scenarios such as floor slabs and roof insulation layers. Due to their low cost and high production efficiency, they were widely used in early 20th-century construction. Among residential buildings constructed in China before 1985, about 80% adopted prefabricated panel structures. During the 1970s and 1980s, approximately 1.2 billion square meters of prefabricated panel houses were built nationwide, covering 12 million households.

Advantages and Disadvantages Analysis

Advantages:

• Economy: Mass production in factories reduces material and labor costs, suitable for large-scale construction needs.
• Construction efficiency: Direct assembly and installation on-site without on-site pouring, shortening the construction period by more than 50%.

Disadvantages:

• Durability: With a lifespan of about 30-50 years, aged concrete is prone to powdering and shedding, similar to "cookie crumbs falling off."
• Seismic resistance: Poor overall integrity, with joints prone to breaking during earthquakes, increasing the risk of panel disintegration.
• Waterproofing: Joints between panels are prone to cracking and leaking due to settlement or thermal expansion and contraction.

Current Status and Policies

With advancements in construction technology, cast-in-place concrete (on-site integral pouring) and prefabricated buildings (factory-produced components assembled on-site) are gradually replacing traditional prefabricated panel houses. Since 2022, China has implemented renovation policies for old buildings, focusing on repair and reinforcement of prefabricated panel houses, and only demolishing buildings identified as dangerous to avoid resource waste caused by large-scale demolition.