Old Prefabricated Panel Factory Building Roof
The old prefabricated panel factory building roof has structural defects such as joint leakage, complex base layer damage, dynamic deformation damaging waterproofing, and vulnerability in the gutter area, and its usage rate has significantly declined due to safety and comfort issues.
Joint Structure Leading to Leakage Issues
The old prefabricated panel roof is assembled from multiple independent concrete panels, with through-joint gaps between them. Over time, affected by temperature-induced expansion and contraction, building settlement, and minor roof loads, these joint gaps continuously open and close. Ordinary waterproof materials (such as thin waterproof coatings and non-standard membranes) have insufficient tensile strength and are prone to cracking or delamination, forming persistent water infiltration channels. For example, in winter, when temperatures drop and the panels contract, the joint gaps narrow; in summer, when temperatures rise and the panels expand, the joint gaps widen. This repeated deformation causes the waterproof layer to fail within a short period, leading to recurring leakage problems.
Scattered and Complex Base Layer Damage
The surface of the prefabricated panels is prone to issues such as unevenness, sanding, peeling, and fine honeycomb cracks due to construction techniques or material aging. After prolonged water immersion, the base layer becomes loose and aged, allowing rainwater to freely flow beneath the waterproof layer along the panel joints or base layer gaps, resulting in hidden leakage. For instance, during the maintenance of a factory building, it was found that the local leakage point on the roof was several meters away from the actual water infiltration location, caused by rainwater spreading to other areas through the loose base layer, making local repairs ineffective in solving the problem.
Dynamic Deformation of the Structure Affecting Waterproof Performance
Seasonal temperature variations cause continuous thermal expansion and contraction of the prefabricated panels, leading to frequent dynamic displacement of the panel gaps. Ordinary waterproof materials (such as non-elastic membranes or thin coatings) have insufficient deformation resistance and are prone to cracking and failure in the short term. For example, a survey shows that the re-leakage rate of prefabricated panel roofs is more than three times that of cast-in-place roofs, mainly because the waterproof layer cannot adapt to the repeated deformation of the panels, resulting in crack propagation or delamination.
Harsh Working Conditions in the Gutter Area
The roof gutter is an area where water, dust, and fallen leaves accumulate, constantly exposed to rainwater scouring and ultraviolet radiation. Conventional waterproof materials are prone to aging, pulverization, peeling, and脱落 (should be 'detachment'), becoming high-risk areas for leakage. For example, maintenance records of an old factory building's gutter show that 80% of the leakage problems are concentrated in the gutter area, as the waterproof layer has been degraded by ultraviolet radiation and mechanically worn over time, allowing rainwater to directly infiltrate the structural layer after the protective layer fails.
Decline in Usage Rate and Industry Trends
With the development of building technology, traditional hollow prefabricated panels have seen a significant decline in usage in newly built rural houses due to leakage, safety, and comfort issues. Industry survey data for 2026 shows that their market usage rate has dropped below 1%. Modern buildings are more inclined to use cast-in-place roofs or new composite materials to enhance waterproof performance and structural durability.
