A branch in a roof valley, lifted flashing near a vent, or debris
piled behind a chimney can direct water where it shouldn’t go. Most
homeowners can spot the clue from the ground with binoculars and a good
photo. Getting on the roof to test it is a different matter.
After strong wind or a heavy leaf drop, look for displaced shingles,
debris, a sagging gutter, and unusual staining at roof penetrations.
Check the attic or top-floor ceiling for new stains, but don’t enter an
unsafe attic or touch wet electrical components. Record the date and
location. A photograph from the same place after the next rain can show
whether a stain is changing.
A qualified roofer can remove debris and inspect flashing, seals, and
any damaged covering. Roof sealant smeared over a leak can hide the
actual path and make a proper repair harder. Moss or algae is not a
reason to use a high-pressure washer on shingles; ask the roof material
manufacturer or roofer about an appropriate cleaning method. Gutter
guards also need checking where leaves collect at their edge.
If water is actively entering, protect the interior where safe and
arrange prompt professional service. I list local trade contacts on Helpful
Resources. My Homeowner
Tools & Supplies page has ground-level drainage ideas; no gadget
there is a reason to work at a dangerous height.