Roof Leaking After Rain — Find the Source
A ceiling stain, wall drip, or attic wet spot that appears during or after rain almost always indicates a roof or envelope breach — but the location of the water inside is rarely directly below where it entered. Water travels along sheathing, rafters, insulation and wall framing before appearing. Finding the actual entry point requires systematic testing, not guesswork.
Possible Sources
Failed step or counter flashing at a wall, chimney or dormer
→ Roof Flashing InspectionFlat roof membrane breach — seam, penetration or drain connection
→ Flat Roof Leak DetectionSkylight frame or flashing failure
→ Skylight Leak DetectionWindow or door head flashing failure (especially in wind-driven rain)
→ Window & Door Leak DetectionBuilding envelope cladding failure (stucco, Hardie, curtain wall)
→ Building Envelope InspectionWhat You Can Check Yourself
- 1
Check the attic (if accessible) immediately after rain — look for active drips, staining or wet insulation
- 2
Note whether the leak appears during wind-driven rain only (suggests envelope/window rather than roof)
- 3
Check gutters and downspouts — blocked gutters cause overflow that stains soffits and enters at eave vents
- 4
Look for visible lifted, cracked or missing shingles or open membrane seams directly above the stain
- 5
Check chimney and skylight flashings for gaps, rust or open joints
How a Specialist Finds the Exact Source
- Attic inspection to identify staining, wet insulation and entry paths
- Thermal imaging from inside maps the moisture extent without opening walls
- Sequential water testing of suspected roof zones — each zone isolated and tested separately
- Drone thermal survey (for flat roofs) identifies wet insulation after sunset
- Written report with the located entry point and repair scope for your contractor
When to Call a Professional
- You've had the area above the stain patched and the leak recurred
- The leak is in a commercial or strata building affecting multiple tenants or units
- You need a documented report for an insurance claim
- You cannot access the attic safely
- The leak appears in wind-driven rain only (harder to reproduce and locate without controlled testing)
Other Common Problems
Frequently asked questions
Why does the stain appear far from the roof penetrations?
Water entering through a flashing gap at a dormer or chimney runs along the top surface of the insulation or the underside of the sheathing, sometimes for several metres, before it finds a low point and drips. The stain marks where it fell, not where it entered.
My roofer says everything looks fine from outside — should I still call?
Yes. Most flashing failures are not visible from a casual visual inspection — the flashing may appear seated but have a failed lap or sealant joint that only allows water in under specific rain intensity or wind direction. Systematic water testing isolates the zone and confirms the source.
Found Your Source — Now Let's Confirm It
LeakInspections.ca — a division of Anyleak.ca and Leak.ca — serves homeowners, strata councils and property managers across BC since 1999.