Possible causes
- Gutters and hoppers overflowing behind fascias
- Wind-driven rain forced under slates or flashings
- Valleys and parapet gutters too small or blocked
- Small defects that only show under heavy flow
Warning signs
- Leaks that appear only in storms
- Water marks near walls rather than mid-ceiling
- Overflowing gutters you can see from the street
Typical solutions
- Clearing and resizing gutters
- Re-forming valley and parapet gutter linings
- Repairing the specific slate or flashing defect