Leak or ponding water on a Philadelphia rowhouse roof?

What should you do first when a Philadelphia ceiling starts to leak?

Protect the inside, not the roof. Move furniture, catch the water, and stay off a wet or iced membrane and away from a bulging ceiling. Photograph everything before you clear up. Then call, and say what room the water is in and what sits above it.

Photographs matter more than people expect. The Pennsylvania Insurance Department advises reporting damage to your insurer promptly, photographing the damage before cleaning up, making temporary repairs such as tarping and keeping the receipts. A phone picture of a wet ceiling, taken before anything is moved, is the cheapest evidence you will ever gather.

Resist going up for a look. Rowhouse roofs are reached through a hatch or from a neighbouring roof, their parapets are low, and a membrane holding water is slick. If the roof needs covering tonight, that is emergency roof repair and it is what the 24-hour line is for.

• Catch the water in a bucket and move what you can out from under the stain.
• Leave a sagging ceiling closed and keep people out from under it.
• Stay off the roof, especially a wet membrane or one with ice at the drain.
• Photograph the damage before you clear anything away, and keep receipts for any temporary work.
• Note what is above the stain: a drain, a parapet, a chimney, a skylight or the party wall.

Why do flat rowhouse roofs leak where they do?

Generally at the edges and the exits rather than in the middle of the field. Parapet and party-wall flashing, the seams around a drain or a scupper, and places where water ponds instead of running off are the usual trouble spots on a low-slope roof of this kind.

Think of the roof as a shallow tray with one way out. The quarter-inch-per-foot fall in the city's Rowhouse Manual only works while the exit is clear, so a blocked drain or a silted scupper turns a working roof into a pond, and standing water finds any seam that has lifted. That is why drain and scupper repair is so often the actual fix behind what looked like a membrane problem.

The edges are the other half of the story. A membrane has to turn up a parapet and stop somewhere, usually against a wall shared with the house next door, and that termination is the detail that fails quietly. Parapet and cornice flashing is its own job for that reason.

Age sets the background. Roughly four in ten homes here date from before 1940 by an older Census-based analysis, so many flat roofs started as built-up tar and gravel and have been covered over since; replacements today are generally a single-ply or modified bitumen membrane. What is on your roof decides whether a repair is sensible, and that is a look-and-see question, not a phone one.

What storm damage actually happens to roofs around here?

Wind, mostly. The National Weather Service office at Mount Holly confirmed eight tornadoes from Tropical Storm Isaias on 4 August 2020, including EF2 tornadoes in Philadelphia and Bucks County, alongside widespread tropical-storm-force gusts. Straight-line microbursts with gusts of 60 to 70 mph have also crossed West and South Philadelphia.

A regional newspaper report put the Philadelphia-area Isaias tornado at 115 mph and on the ground for about 20 miles, from Northeast Philadelphia toward Doylestown. Wind that strong lifts membrane at the edges, peels flashing off a parapet, strips slate and shingle from a pitched twin, and leaves a roof that looks intact from the street.

The microbursts are the quieter risk. The Mount Holly office described a series of at least four of them, with gusts of 60 to 70 mph, crossing far southern Montgomery County, West Philadelphia and South Philadelphia inside about half an hour, and said it was straight-line wind rather than a tornado. Damage like that is scattered, so one block is stripped and the next is untouched.

After any of it, the sensible order is cover first and claim second. Storm damage roof repair deals with the roof; what the insurer will want from you is set out in the Isaias damage guide.

Does roof work in Philadelphia need a permit or a historic review?

Most roof replacements in the city need a permit from Licenses and Inspections, which the roofer files. An EZ permit, filed without plans, is mostly processed within five business days. On a historic-district property, roof work visible from the street may need Historical Commission review before the permit issues.

The inspection sequence is worth knowing because it shapes the schedule. On minor permits the city inspects after the old roofing has been removed and the new material is on site, and the new membrane or coating should not go down until that inspection passes. A roofer who plans for it does the tear-off and the inspection on the same day rather than leaving a deck open.

Historic review is about what the street can see. The Historical Commission's Roofs Guideline favours work that is inconspicuous from the public right-of-way, and its reports treat slate replacement as something contemplated where deterioration requires it, with exceptions for mansards, turrets and other character-defining features. A flat roof hidden behind a parapet is generally treated more simply. The Commission confirms for a specific address.

Outside the city the rules change hands. Delaware and Montgomery County townships and boroughs issue their own permits, and in Camden County the municipality does, not Licenses and Inspections. The roof permit guide goes through it in order.