Prefabricated Panel Roofing Method

The prefabricated panel roofing method mainly includes three core steps: laying prefabricated panels, waterproofing treatment, and thermal insulation. It is necessary to strictly follow the construction sequence and pay attention to quality control. The details are as follows:

I. Laying Prefabricated Panels

1. Material Selection and Inspection: Select prefabricated panels with matching specifications according to the design drawings and roof dimensions. Each panel should be inspected before laying to ensure there are no cracks, damages, or honeycomb-like surfaces, so as to avoid potential leakage or structural safety hazards caused by material problems in the later stage.
2. Laying Requirements: The prefabricated panels should be neatly arranged in the designed direction, with the gap width controlled between 10 - 20mm to ensure uniformity. The connection between panels should be firm. Cement mortar or special adhesive can be used for joint filling, and a brick trowel should be used to compact the filling in layers to avoid hollowing. The holes at both ends should be sealed with fine aggregate concrete for 300 - 400mm to prevent rainwater backflow.

II. Waterproofing Treatment

1. Material Selection:
   • Flexible Waterproofing: SBS modified asphalt waterproofing membrane or polyurethane waterproofing coating are preferred, which are suitable for areas with large deformations (such as panel joints and pipe openings).
   • Rigid Waterproofing: Fine aggregate concrete (with Φ4@100 two-way steel mesh) or waterproof mortar can be used, which are suitable for roofs with large slopes.
2. Construction Steps:
   • Base Layer Treatment: Clean the dust and oil stains on the surface of the prefabricated panels to ensure they are dry and flat. For joint parts such as panel joints and pipe openings, first apply two coats of elastic K11 waterproofing coating, then apply a 2cm thick layer of waterproof mortar, and fill the separation joints with sealant.
   • Overall Waterproof Layer: The flexible waterproofing membrane should be laid from the low to the high place, with an overlap width of not less than 100mm. The rigid waterproof layer should be provided with separation joints (with a spacing of not more than 6m) to avoid cracking.
   • Drainage Design: The roof drainage slope should be not less than 2%, and the longitudinal slope of the gutter and eaves gutter should be not less than 1% to ensure smooth drainage and avoid water accumulation.

III. Thermal Insulation

1. Material Selection: Select materials with low water absorption according to the climatic conditions, such as expanded polystyrene (EPS) board, rock wool board, or extruded polystyrene (XPS) board, to avoid the failure of the thermal insulation layer due to water absorption.
2. Construction Methods:
   • Conventional Method: First lay the thermal insulation layer (such as perlite), and then do the waterproof layer. It is suitable for dry areas, but attention should be paid to the protection of the waterproof layer.
   • Inverted Method: First do the waterproof layer, and then lay the thermal insulation layer. The service life of the waterproof layer is longer, but the cost is higher.
   • Elevated Thermal Insulation: Build bricks 10 - 20cm high on the roof and install prefabricated panels to form an elevated layer. It is suitable for hot summer areas, and attention should be paid to insect prevention and ventilation.

IV. Precautions

1. Construction Sequence: Strictly follow the process of "structural layer acceptance → base layer cleaning → leveling layer → additional layer → waterproof layer → thermal insulation layer → protective layer → curing" to avoid quality hazards caused by reversed sequences.
2. Quality Control: Focus on inspecting the waterproofing treatment of joint parts such as panel joints, pipe openings, and parapet corners to ensure there are no omissions. The materials should comply with national standards (such as GB 18445 - 2012 Cementitious Capillary Crystalline Waterproofing Materials).
3. Maintenance Management: Regularly inspect the roof after construction is completed, and promptly repair cracks or damages to prevent small problems from developing into large leakages.