Inspection of Prefabricated Slab Structure Houses

The inspection of prefabricated slab structure houses should focus on three core dimensions: structural integrity, key components, unauthorized modifications, and usage environment. The specific key points are as follows:

I. Structural Integrity and Foundation Inspection

1. Foundation: Focus on checking for obvious settlement marks on the ground around the house and whether there are height differences between indoor and outdoor floors. Observe whether the bottom of the walls has diagonal cracks caused by uneven foundation settlement. Such cracks are usually triggered by insufficient foundation bearing capacity and may threaten structural safety.
2. House Tilt: Stand at a distance and visually inspect whether the house as a whole shows visible tilting or warping. Tilt may be caused by foundation settlement or structural force imbalance, and further testing is required to determine whether the tilt rate exceeds the standard limits.

II. Special Inspection of Key Components

1. Prefabricated Floor Slabs:
   • Slab Bottom Cracks: Check the ceiling for horizontal through-cracks or slab joint cracking. Such cracks may be caused by excessive floor slab stress or material aging.
   • Deflection Deformation: Observe whether the middle of the floor slab shows significant downward bending. Long-term deflection may pose a risk of floor slab fracture.
   • End Damage: Inspect the parts of the prefabricated slabs that rest on the walls to confirm whether the concrete is loose or crumbling and whether the steel bars are exposed and rusted. End damage can reduce the load-bearing capacity of the floor slab.
2. Load-Bearing Walls:
   • Stress Cracks: Focus on checking for vertical and diagonal cracks on the load-bearing walls, as well as cracking and downward pressure deformation above the lintels of door and window openings. Such cracks may be caused by excessive wall stress or foundation settlement.
   • Wall Weathering: Check whether the bricks or masonry at the bottom of the walls are severely weathered and flaking. Weathering can weaken the wall cross-section and reduce structural stability.
   • Structural Measures: Confirm whether the house is equipped with ring beams and constructional columns. For brick-concrete prefabricated slab houses of three stories or more, the overall seismic resistance and safety will be significantly reduced without such structures.
3. Node Connections:
   • Lap Length: Check whether the support length of the prefabricated slabs on the brick walls complies with the standards (should not be less than 80mm). Insufficient support may cause floor slab slippage.
   • Tie Conditions: Observe whether the corners and junctions of the walls are separated or cracked. Failure of node connections can weaken the overall structural integrity.

III. Inspection of Unauthorized Modifications and Usage Environment

1. Removal or Modification of Load-Bearing Walls: Verify whether there has been unauthorized removal of load-bearing walls, creation of door and window openings in load-bearing walls, or enlargement of opening sizes. Such actions can directly disrupt the structural force transmission system.
2. Unauthorized Additions (Increased Load): Check whether additional floors have been privately built on the roof, mezzanines have been added, or heavy equipment and large water tanks have been stacked on the floor slabs. Overloading may cause damage to the floor slabs or walls.
3. Change of Use: If a house originally designed as a residence is converted into a crowded place (such as a restaurant or KTV), a significant increase in live load may trigger safety accidents.

IV. Post-Inspection Handling
Preliminary inspections cannot replace professional appraisals. General hidden dangers found should be verified by professional technicians. If the house has dangerous hidden dangers, a qualified appraisal unit should be commissioned to classify the level according to the "Standards for the Appraisal of Dangerous Houses" (JGJ 125-2016) (Level A: Safe, Level B: Individually Dangerous, Level C: Partially Dangerous, Level D: Overall Dangerous), and reinforcement or demolition measures should be taken based on the appraisal results.