Roofing in Wilmington starts on the fall line, with older roofs on the hills and lower, wetter roofs toward the Christina and the Delaware. Slate and early shingles still cover some brick houses above the Brandywine. Additions and porch roofs fail on their own schedule. Limbs from hillside trees open valleys that a bare lot would never see. Say whether the house is up on the rock or down on the flat before you describe the stain.
Flashing cut into old brick is the usual suspect, especially at a chimney or where a later wing meets the main house. Ice on a north slope of the hills backs up under the covering. Down on the river side, a low roof stays damp and grows dark streaks because the air never quite dries. Tell us if the leak arrives with wind, with a thaw, or only after a day of rain has soaked the brick. The timing points at the joint.
Access changes with the street. A steep hill lot, a narrow side yard, and a roof over a finished attic all change how the work happens. Several layers may already be on an older deck. A patched valley under an oak is not a whole-roof story until someone looks, but you should mention the patch. Do not climb a slate slope to be helpful. Say what you can see from the ground and from the attic hatch.
Note soft fascia, missing pieces, and gutters full of hillside leaves. If the stain is near an outside wall, say so. If it is under a bath, say that too so the call does not chase the wrong trade. Party walls are less universal here than in a pure row city, but attached houses near the rivers still share the problem of a seam you cannot see from the front sidewalk.
Say repair or replacement, and name slate, shingle, or a low rear roof if you know it. Roofing in Wilmington is the fall line: ice and limbs on the hills, lingering damp toward the Christina, and flashing into brick that has been there a long time. Call the number on this page.