Journal of Engineering Research and Reports

This paper presents a case-based account of a composite waterproofing system applied to the basement slab of the Junpin Country Garden project in Nanhai District, Foshan City. The project includes a two-storey basement with a partially single-storey section, approximately 1,500 underground parking spaces and a total construction area of approximately 20 × 10⁴ m². The basement slab is located at a depth of approximately 8.5 m in an environment characterised by relatively high groundwater levels. The waterproofing design combines structural self-waterproofing with an external system comprising a 1.5 mm single-component polyurethane waterproof coating and a 1.2 mm high-density polyethylene (HDPE) self-adhesive film membrane. The study describes substrate preparation, priming, coating application, membrane laying, overlap and termination treatment, and additional reinforcement at construction joints, post-pouring belts, pile heads, corners and pipe penetrations. It also outlines material acceptance, witness sampling, concealed-works inspection and construction-stage quality-control measures. The reported site observations indicate that the basement slab and side walls remained dry, with no leakage observed more than two years after completion. The account suggests that the combination of coating and membrane, together with attention to detailing and inspection, can support satisfactory waterproofing performance under the conditions encountered at this project. These observations provide practical guidance for comparable basement waterproofing works, although longer-term performance cannot be established from the reported observation period.