How to Identify Prefabricated Panel Houses

The identification of prefabricated panel houses can be comprehensively judged by observing structural features, construction age, wall construction, pipeline laying methods, drilling tests, and safety appraisal reports. The specific methods are as follows:

1. Observe the structural features of the house The floor slabs of prefabricated panel houses are composed of long, strip-shaped panels spliced together, with obvious gaps between the panels. The splicing joints may exhibit misalignment or cracks due to settlement or construction errors. If the surface of the floor slab shows regularly arranged splicing marks and the gap widths are uneven, it can be preliminarily determined to be a prefabricated panel structure.

2. Verify the construction age According to the development pattern of domestic construction technology, houses built more than 15 years ago mostly used prefabricated panels, while those built after 15 years generally use cast-in-place slabs. However, it should be noted that in some areas, due to technological lag or cost factors, the use of prefabricated panels may extend to 10 years ago; in the renovation of old residential areas, some prefabricated panel houses may continue to be used through reinforcement and renovation, requiring comprehensive judgment in combination with other features.

3. Inspect the wall construction

• Connection construction: There may be special structures at the joints between the prefabricated panels and the walls, such as reserved steel bars or concrete pouring nodes, used to enhance the overall structural integrity.
• Load-bearing system: If the internal walls of the house have no beams and there are no columns at the corners, it indicates that the floor slab is a prefabricated panel (relying on the walls for load-bearing); if there are beams above the walls and columns at the corners, it is a cast-in-place slab (with an independent load-bearing structure).

4. Observe the pipeline laying method Pipelines (such as drainage pipes and electrical conduits) in prefabricated panel houses are usually laid along the walls or columns, and holes need to be reserved in the floor slabs; in cast-in-place slab houses, the pipelines can be directly embedded in the concrete, and there are no obvious holes on the surface of the floor slabs. If regularly arranged reserved holes are found on the floor slab (such as in bathroom and kitchen areas), it can assist in determining that it is a prefabricated panel.

5. Drilling test method During the production of prefabricated panels, holes with a diameter of about 8 centimeters are reserved every 3 centimeters or so (used to reduce weight or for threading). Use an impact drill to make 3 holes in the floor slab at intervals of 5 centimeters:

• If holes are hit: it indicates a prefabricated panel;
• If all are solid concrete: it is a cast-in-place slab. Note: Before drilling, confirm the thickness of the floor slab (prefabricated panels are usually 12-15 centimeters thick, while cast-in-place slabs are 10-12 centimeters thick) to avoid damaging the structural safety.

6. Refer to the safety appraisal report According to the "Standards for the Appraisal of Dangerous Houses", prefabricated panel houses can be divided into four levels:

• Level A: The structure is intact with no dangerous points;
• Level B: Individual components are slightly damaged but do not affect use;
• Level C: Some load-bearing structures have failed and need reinforcement;
• Level D: The overall load-bearing structure has failed and needs to be demolished and rebuilt. The appraisal report issued by a professional institution is an authoritative basis, but it needs to be verified in combination with on-site features.

Identification precautions:

• A single method may have errors, and multiple features need to be comprehensively judged;
• Old houses may have been renovated (such as cast-in-place layers covering prefabricated panels), and the surface decorative layers need to be stripped off for observation;
• Drilling tests should be carried out in non-load-bearing areas to avoid damaging the structural safety.