Precautions for Precast Panel Houses
When using precast panel houses, it is necessary to handle with caution in terms of purchase, installation, earthquake resistance, waterproofing, renovation, property rights planning, and insurance to ensure safety and compliance.
Purchase and Materials: Choose precast panels produced by reputable large manufacturers, ensuring that the steel bars are prestressed, the concrete strength is not less than C30, and the specifications and quantity of steel bars comply with national standards. During purchase, inspect the appearance to avoid defects such as cracks, honeycombs, and holes. Use a magnet to check the diameter of the steel bars (those less than 8 mm are unqualified) and check the cement grade (packages not labeled with C25 or above are not recommended).
Installation and Construction: When placing precast panels on concrete components (such as ring beams), the length should be no less than 80 mm; when placing them on walls, the length should be no less than 100 mm. When installing, leave a gap of 20-40 mm between two panels, and apply mortar at the bottom ends of the panels (pour cement mortar to enhance adhesion). The holes at both ends of the precast panels on the wall should be filled with concrete. It is strictly prohibited to randomly cut holes or slots, or use them in kitchens or bathrooms. The panel joints should be cleaned of debris and then poured with cement mortar and vibrated densely. For larger gaps, use concrete for on-site pouring and curing; the use of bricks for filling is prohibited. Check the original construction records to confirm whether the panel joints are filled with high-strength grout and whether earthquake-resistant columns are added at the corners of beams and columns.
Earthquake Resistance and Safety: Precast panel houses have poor integrity and weak earthquake resistance. When using precast panels for self-built low-rise brick-concrete houses in non-earthquake-resistant areas, ensure correct usage. Before purchase, require the seller to provide an earthquake resistance report and focus on checking whether the floor connections are reinforced with steel plates.
Waterproofing and Maintenance: Kitchens and bathrooms should undergo a 72-hour closed water test. It is recommended to use an endoscope to inspect the interior of the wall panels to prevent water accumulation in cavities leading to mold. Set aside 0.5% of the house price annually for maintenance costs, inspect cracks every six months, and report for repair if they exceed 3 mm; if the earthquake resistance rating is Class C, spend 120-200 yuan for reinforcement.
Renovation Restrictions: It is strictly prohibited to modify load-bearing walls. If non-load-bearing walls need to be modified, a professional institution should calculate the load, and the weight of items stacked per square meter should not exceed the weight of two bags of cement.
Property Rights and Planning: Carefully verify the property rights term. Houses with a designed lifespan of 30 years that have been in use for more than 18 years require annual inspections. When purchasing, check the safety appraisal report and require the seller to sign a reinforcement agreement if the remaining lifespan is less than 60%. Query local demolition plans; if the house is located in a renovation area from 2025 to 2035, the compensation distribution method should be clearly specified in the contract.
Insurance: It is recommended to purchase structural insurance with an annual fee of 0.3% to cope with potential risks.
