Roof and Wall Removal in Prefabricated Slab Houses

Caution must be exercised when removing roofs and walls in prefabricated slab houses, and professional standards must be strictly followed. Otherwise, structural instability or even collapse risks may arise.

1. Wall Nature Assessment

In rural self-built houses, the central walls are often load-bearing walls, with prefabricated slabs directly placed on them to bear the weight of the upper structure and transfer it to the foundation. Removing these walls would result in the loss of support for the floor slabs, leading to overall structural instability. It is essential to entrust a professional agency to assess the nature of the walls, clearly marking the function of each wall (load-bearing/non-load-bearing). Unauthorized construction without assessment is strictly prohibited.

2. Inspection of Prefabricated Slab Characteristics

Prefabricated slabs in houses over 30 years old may experience a decrease in load-bearing capacity due to aging, significantly increasing the risk of removal. Before renovation, a comprehensive inspection of the prefabricated slabs is required:

• Focus on inspecting the crack width at the manufacturing points. If the width exceeds 0.3 millimeters, special treatment is needed (such as carbon fiber reinforcement or partial replacement).
• Evaluate the rust and looseness at the connection points between the prefabricated slabs and the walls to ensure reliable joint connections.

3. Essential Reinforcement Measures

If renovation is indeed necessary, the following measures must be taken to ensure safety:

1. Roof Beam Installation: Install steel beams on the roof to transfer loads. The cost of steel beams is approximately 200-400 yuan per meter, and appropriate specifications should be selected based on the span.
2. Connection Between New and Old Structures: Use chemical anchors for reliable connections. Each anchoring point must bear a load of ≥1 ton to ensure the integrity of the renovated structure.
3. Temporary Support System: Before construction, install steel pipe supports every 1.2 meters along the length of the prefabricated slabs. For key nodes, use H-shaped steel beam underpinning (with a beam section of ≥200*200 millimeters) to prevent the prefabricated slabs from falling during removal.

4. Construction Precautions

1. Removal Sequence: Follow the principle of "middle first, then sides," removing in segments symmetrically. The daily removal amount should not exceed 30% of the total floor area.
2. Real-time Monitoring: Monitor the stress changes in the support system during removal. If abnormalities are detected, construction should be stopped immediately.
3. Prohibition of Impact Removal: It is strictly prohibited to use heavy hammers to impact walls or prefabricated slabs to avoid impact damage to the foundation.

5. Alternative Solution Suggestions

If the renovation risk is too high, consider the following non-destructive solutions:

• Retain the lower part of the wall as a half-wall partition (height of 1-1.2 meters) to balance spatial transparency and structural safety.
• Create arched doorways (span ≤1.8 meters) to reduce damage to load-bearing structures.
• Use lightweight partitions (such as gypsum board partitions, approximately 80-120 yuan/㎡) to redivide the space.
• Optimize the spatial layout using non-structural means such as glass partitions and movable furniture.