How to Identify Prefabricated Panel Houses
Identifying prefabricated panel houses can be done through the following methods:
1. Observe the floor slab structure Prefabricated panels typically exhibit a regular block shape, with noticeable gaps between panels and lower surface flatness. In contrast, cast-in-place concrete floor slabs are formed as a whole, with a smooth and flat surface and no obvious拼接 (splicing) marks. By directly observing the surface characteristics of the floor slab, you can make a preliminary judgment on the structural type.
2. Check the construction year According to the evolution of building codes, older houses (especially those built more than 15 years ago) mostly used prefabricated panel structures. After 2003, the state prohibited the use of prefabricated panels in newly built commercial housing, so commercial housing built after 2003 is basically cast-in-place slabs. If the house was built before 2003, especially in old residential areas, the likelihood of using prefabricated panels is higher.
3. Tap the floor slab to listen for sounds Tap the floor slab lightly with a hard object (such as a key). Prefabricated panels, due to the presence of internal cavities, will produce a clear and long-echoing sound when tapped, with a single direction of vibration transmission. Cast-in-place slabs, being dense and cavity-free, produce a dull sound, and the vibration spreads in all directions. This method should be combined with other characteristics for a comprehensive judgment.
4. Examine the house design drawings If you can obtain the original design drawings of the house, you can directly check the floor slab structure annotations. If the drawings clearly indicate “prefabricated panels” or “assembled floor slabs,” it can be confirmed as a prefabricated panel house; if it indicates “cast-in-place concrete floor slab,” it is a cast-in-place structure.
5. Observe the pipeline installation areas Prefabricated panels require reserved pipeline holes or column supports, so regular arrays of holes or columns can be seen at pipeline installation areas. Cast-in-place slabs are formed as a whole, and pipelines can be directly embedded in the concrete without the need for reserved holes, resulting in no irregular openings on the surface.
6. Check the internal wall structure Due to span limitations, prefabricated panel houses typically have no beams inside the walls and no columns at the intersections of walls. Cast-in-place slabs can achieve large-span structures, with beams often present above the walls and columns at wall intersections. Observing the relationship between walls and beams and columns can assist in judgment.
7. Drill holes in the floor slab for verification Prefabricated panels have holes with a diameter of 8 centimeters reserved every about 3 centimeters during production, while cast-in-place slabs do not have such holes. Use an impact drill to make three holes 5 centimeters apart on the floor slab. If you drill into a cavity, it indicates a prefabricated panel. This method may damage the floor slab structure and should be used with caution, prioritizing non-destructive testing methods.
8. Observe the characteristics of ceiling cracks Cracks on the ceiling of prefabricated panel houses are mostly distributed in parallel straight lines, resembling regular marks made with a ruler. Cracks on cast-in-place slabs have irregular directions, appearing in a mesh or chaotic pattern. The characteristics of cracks should be analyzed in combination with the service life of the house to avoid misjudgment.
