For bathroom or kitchen ceiling leak repair (often from upstairs flat leakage), experts use non-destructive methods: identify overflow points, seal pipe penetrations with silicone/PU sealant, apply hydraulic cement for active flow, then coat the affected slab underside with crystalline waterproofing slurry that penetrates concrete pores. Terrace treatment includes cleaning, crack fill... https://shakuraconstruction.sg/ceiling-leak-repair/