The line where the roof slab meets the parapet wall is a classic weak spot. Temperature changes and slight movement often create hairline cracks right along this junction. If left untreated, water can sneak in through these lines and travel down inside walls.
If you see visible cracks, crumbling plaster, or old, peeling patchwork in this area, it’s a hint that seepage either already is or soon could be a problem. A proper repair job—cleaning, sealing, re-coating—will be needed at some point.
Noticing this early helps you ask the right questions about past leaks in top-floor flats.
