Prefabricated Slab Building Roof

The roof of prefabricated slab buildings has characteristics such as easy leakage due to the spliced structure, poor thermal insulation, weak earthquake resistance, and a limited service life, requiring targeted renovation and attention to policy guidance.

Structural Characteristics and Leakage Risks

The roof of a prefabricated slab building is assembled from multiple prefabricated concrete slabs, which come in two types: solid and hollow. The spliced structure results in natural gaps between the slabs, which are the core channels for water infiltration. Over time, affected by temperature differentials, building settlement, and slight roof loads, these gaps continuously open and close, causing ordinary waterproofing materials to crack or delaminate, forming persistent water infiltration channels. Additionally, base layer defects (such as crack openings and loose, sandy leveling layers) and the aging and failure of old waterproofing layers further exacerbate leakage issues, manifesting as widespread roof leakage, dampness and mold on the interior walls of the top floor, and peeling of the ceiling. Rainwater may freely flow beneath the waterproofing layer through gaps in the slabs or the base layer, resulting in a mismatch between the leakage points and the water infiltration points, making local repairs difficult to cure the problem. The gutter area, due to its harsh working conditions, is prone to the aging and pulverization of conventional waterproofing, becoming a high-risk node for leakage.

Shortcomings in Thermal Insulation and Earthquake Resistance

The roof of a prefabricated slab building has poor thermal insulation, failing to effectively block heat in summer and retain warmth in winter. Rural self-built houses often require a secondary covering of roofing materials to compensate. Its earthquake resistance is also weak, as the spliced structure lacks overall integrity, making it prone to collapse in earthquake-prone areas, a common issue in existing prefabricated slab buildings.

Service Life and Renovation Plan

The designed service life of the roof of a prefabricated slab building is approximately 30-50 years. To address common issues such as easy deformation, slab gap cracking, and frequent hidden water channeling, a systematic renovation plan can be adopted: including full roof clearance,精细化 (fine) repair of base layer defects, rigid filling and reinforcement of slab gaps, full-area waterproofing with thickened national standard roll materials, and specialized exposed waterproofing reinforcement for gutters. This plan abandons traditional local gap-filling techniques, using only national standard genuine waterproofing materials from Oriental Yuhong throughout the process, with standardized construction and providing a 5-year formal written warranty.

Development and Policy Guidance

Prefabricated slab buildings originated in the early 20th century, with most residential buildings constructed in China before 1985 adopting this structure. With the development of building technology, cast-in-place concrete and prefabricated buildings have gradually replaced traditional prefabricated slab houses. Since 2022, China has implemented a policy of renovating old buildings, focusing on repairing and renovating prefabricated slab houses and only demolishing those that meet the criteria for dangerous buildings.