How to Detect Prefabricated Panel Houses

To detect prefabricated panel houses, it is necessary to first determine the structural type and then inspect for potential safety hazards. The specific methods are as follows:

I. Determining Whether It Is a Prefabricated Panel Structure

1. Examine the Construction Year: Houses built more than 15 years ago are mostly prefabricated panel structures, while those built in the last 15 years generally use cast-in-place slabs.
2. Observe the Floor Panel Characteristics: Prefabricated panels are regular in shape with visible gaps between them; cast-in-place slabs have a smooth surface without any joints.
3. Tap and Listen: Gently tap the floor panel with a hard object. If the sound is clear and the echo is long, it may be a prefabricated panel; if the sound is dull, it may be a cast-in-place slab.
4. Inspect the Pipe Installation Areas: Prefabricated panel structures usually have columns or reserved holes, while cast-in-place slabs do not have such features.
5. Observe the Wall Structure: If the walls have no beams and no columns at the intersections, it is mostly a prefabricated panel structure; if there are beams above the walls and columns at the intersections, it is a cast-in-place structure.
6. Drill for Verification: During the production of prefabricated panels, holes with a diameter of about 8 centimeters are reserved every 3 centimeters. If an empty space is encountered during drilling, it can be confirmed as a prefabricated panel.
7. Consult the Design Drawings: If the original design drawings of the house are available, the type of floor panel structure can be directly checked from the annotations.

II. Inspecting for Safety Hazards in Prefabricated Panel Houses

1. Overall Structural and Foundation Inspection:
   • Check the foundation and observe whether there are any settlement marks on the ground around the house, whether there are height differences between the indoor and outdoor floors, and whether there are diagonal cracks at the bottom of the walls.
   • Visually inspect whether the house is tilted or shows signs of 'warping' or 'twisting'.
2. Special Inspection of Core Components:
   • Prefabricated Floor Panels: Check the ceiling for horizontal through cracks or joint cracks, whether the middle of the floor panel is sinking or bending, and whether there is concrete looseness or exposed and rusted steel bars at the ends where the panel rests.
   • Load-Bearing Walls: Check for vertical or diagonal cracks in the walls, whether the lintels above door and window openings are cracked or deformed, whether the bricks at the bottom of the ground floor walls are weathered and spalling, and confirm whether ring beams and constructional columns are set.
   • Node Connections: Check whether the support of the prefabricated panels on the walls is firm, and whether the corners and intersections of the walls are separated or cracked.
3. Inspection for Unauthorized Renovations and Usage Environment:
   • Verify whether load-bearing walls have been unauthorizedly removed, whether door and window openings have been added or enlarged on load-bearing walls.
   • Check whether additional floors have been built on the roof, whether mezzanines have been added, or whether heavy objects have been stacked on the floor panels.
   • Confirm whether the originally designed residential house has been converted into a densely populated business premises.