How to Distinguish Prefabricated House Panels

Distinguishing whether a house uses prefabricated panels can be done through the following methods:

1. Observe the floor slab structure
Prefabricated panels typically exhibit a regular block-like structure, with noticeable gaps between panels and possible slight irregularities or seam marks on the surface. In contrast, cast-in-place slabs are poured as a whole, resulting in a smooth, flat surface without obvious seams, offering greater structural integrity. By directly observing the surface features of the floor slab, you can make a preliminary assessment of the structural type.

2. Check the construction year
The construction year of the house is an important reference. Houses built earlier (approximately 15 years ago or more) often used prefabricated panel structures, especially multi-story brick-and-concrete buildings. In recent years, newly constructed houses generally employ cast-in-place concrete structures due to the advantages of cast-in-place techniques in terms of earthquake resistance and overall structural integrity. However, it should be noted that some older houses that have been renovated or refurbished may use a mix of structural types, so verification through other methods is necessary.

3. Tap the floor slab to listen for sounds
Using a hard object (such as a metal rod), lightly tap the floor slab. Prefabricated panels, due to their internal hollow spaces or seams, will produce a clear, long-lasting echo. In contrast, cast-in-place slabs, filled densely with reinforced concrete, will emit a dull, short sound. This method requires testing at multiple points to avoid misjudgment due to local装修 (renovation) coverings.

4. Inspect the areas where pipes are laid
Prefabricated panel structures require pre-drilled holes for pipes or support from columns, so areas where pipes are laid often show regularly arranged holes or columns. Cast-in-place slabs, being poured as a whole, allow pipes to be directly embedded in the concrete without the need for additional holes or columns. Inspecting areas with dense piping, such as kitchens and bathrooms, can aid in judgment.

5. Observe the interior walls of the house
The load-bearing system of a prefabricated panel house relies on the walls, so there are usually no obvious beams above the walls, and no columns at the intersections of walls. In contrast, a cast-in-place slab house, using a frame structure, will have visible beams above the walls and columns at the corners to reinforce overall structural integrity. This method should be combined with the house's structural drawings or guidance from a professional for observation.

6. Drill holes in the floor slab for verification
Prefabricated panels are typically manufactured with holes spaced every 3 centimeters and with a diameter of about 8 centimeters (used to reduce weight or for wiring). Using an impact drill, make three holes spaced 5 centimeters apart in the floor slab. If the drill enters a hollow space, it indicates a prefabricated panel. This method is destructive and requires permission from the property management and operation by a professional to avoid damaging structural safety.

7. Check the house's design drawings
If the original design drawings of the house can be obtained, you can directly check the floor slab structure description. The drawings will clearly indicate whether it is a "prefabricated panel" or "cast-in-place slab" and will include parameters such as panel thickness and reinforcement, providing the most accurate basis for judgment.