House Renovation with Prefabricated Panels

When renovating houses with prefabricated panels, it is essential to focus on structural characteristics and common issues, achieving long-term waterproofing and structural reinforcement through systematic treatment.

I. Core Issues with Prefabricated Panel Roofs

Prefabricated panel roofs are composed of multiple prefabricated concrete panels joined together, and their structural characteristics lead to the following common problems:

1. Panel Joint Cracking: Natural gaps exist between panels, which can expand due to temperature variations, building settlement, and other factors, compromising structural integrity.
2. Substrate Loosening: Over time, concrete at the joints may deteriorate due to weathering and water infiltration, leading to powdering and detachment, reducing the load-bearing capacity of the substrate.
3. Waterproofing Layer Failure: Aging of original waterproofing materials or construction defects can cause rainwater to penetrate along panel joints or through a loosened substrate, resulting in roof leaks and dampness or mold on interior walls.
4. Limited Service Life: Prefabricated panel houses are typically designed for a lifespan of about 40 years. Older houses often exhibit issues such as peeling wall finishes, wall cracks, and reduced sound insulation and thermal insulation performance, necessitating an assessment of whether partial repairs or complete reconstruction are needed.

II. Key Steps in the Renovation Plan

To address the above issues, systematic renovation should include the following steps:

1. Full Roof Clearance: Thoroughly remove the original waterproofing layer, damaged substrate, and debris to ensure a flat and clean construction surface for subsequent treatment.
2. Precision Repair of Substrate Defects: Use high-pressure grouting or cement-based materials to fill loose or cracked areas, restoring substrate density and enhancing adhesion to the waterproofing layer.
3. Rigid Joint Filling and Reinforcement of Panel Joints: Fill panel joints with high-strength polymer mortar or specialized joint-filling materials to create rigid connections and suppress cracking caused by temperature-induced deformation.
4. Full-Coverage Waterproofing with National Standard Thickened Membranes: Lay thickened waterproofing membranes (such as SBS modified bitumen membranes) that comply with national standards, covering the entire roof and panel joint intersections to form a continuous waterproof barrier.
5. Enhanced Waterproofing for Gutters with Specialized Exposed Coatings: For roof drainage gutters and other areas prone to water accumulation, use weather-resistant exposed-type waterproofing coatings for reinforcement, extending service life.

III. Construction and Material Requirements

1. Standardized Precision Construction Process: Strictly adhere to construction specifications, such as ensuring substrate treatment meets dry and dust-free standards, controlling lap width and hot-melt temperature during membrane laying to avoid blistering or leakage risks.
2. Genuine Waterproofing Main Materials: Select waterproofing membranes, joint-filling materials, and coatings that have passed national testing to ensure materials meet requirements for aging resistance and tensile strength, guaranteeing renovation quality from the source.

IV. Recommendations for Renovating Old Houses

If a house is nearing its design lifespan or has severe structural damage (such as cracks in load-bearing walls or foundation settlement), it should be evaluated by professionals to determine if partial repairs are suitable. If repair costs are excessively high or safety cannot be guaranteed, complete reconstruction may be advisable to thoroughly address the inherent defects of prefabricated panel structures.