Flat Roof Repair and Replacement for Philadelphia Rowhomes

Most South Philly homes have the same roof: a flat, low-slope roof sitting between two party walls, draining to the back of the house. It's a simple design that's worked for a century, but it fails in predictable ways. Water ponds in low spots, flashing pulls away from the parapet, and seams open up after a few hard winters.

Top Tier Roofing is based at 200 Jackson Street in South Philadelphia, and flat rowhome roofs are most of what we work on. We repair leaks, recoat roofs that still have life in them, and replace roofs that don't, across South Philly, Center City, and the surrounding neighborhoods.

Get a Free Flat Roof Estimate  |  Call (215) 330-2664 (24/7 leak response)

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Why Rowhome Flat Roofs Leak

When we're called out for a leak in South Philly, it almost always comes back to one of these:

• Ponding water. A flat roof isn't truly flat. It needs a slight pitch toward the rear drain or scupper. Over decades the deck sags, and water sits in the low spots for days. Standing water breaks down the membrane and finds every weak seam.
• Party wall and parapet flashing. The joint where your roof meets the brick party wall is the most common leak point on a rowhome. Mortar cracks, old flashing shrinks or was just caulked, and water runs down inside the wall. Often you'll see the stain on an interior wall rather than the ceiling.
• Clogged drains, scuppers, and pole gutters. Leaves, grit, and roof deck debris block the drain at the back of the roof. Once water can't leave, it backs up under the membrane. (We also handle gutters and downspouts.)
• Failing seams. Rubber (EPDM) roofs are installed in sheets. After years of summer heat on a dark roof and winter freeze-thaw cycles, seam adhesive lets go.
• Old patches and too many layers. Many Philly roofs have been patched with tar or coated several times over. Each layer hides the real problem, and once a roof has two coverings, city code requires a full tear-off at replacement.
• Roof decks, HVAC units, and satellite mounts. Every bolt and foot traffic path is a chance for a puncture. Roof decks in particular need the membrane and flashing done right underneath them. Putting in a roof deck? See our EPDM roof page.

If your neighbor's roof is in bad shape, it can affect yours too, because the two roofs meet at the party wall. We'll tell you honestly if the source of the leak is next door.

Flat Roof Repair

A lot of flat roofs we inspect don't need replacing. If the membrane is mostly sound, a targeted repair can buy years:

• Re-flashing the party walls and parapets
• Sealing or re-seaming open EPDM seams
• Patching punctures and blisters
• Clearing and rebuilding drains and scuppers
• Repairing small sections of rotted deck
• Emergency tarping and leak stops, 24/7

We'll show you photos of what we found on the roof before we recommend anything, so you can see the problem yourself.

Emergency leak? Call (215) 330-2664 any time. We can usually have someone out the same day. See our emergency roof repair page for more.

Roof Coatings: When They Make Sense

A silicone or acrylic coating over an existing roof can extend its life for several years at a fraction of the cost of replacement. It works best when the roof is dry underneath, the seams are still mostly intact, and there's no widespread ponding.

A coating is the wrong call when water is already trapped under the membrane or the deck is soft. Coating a wet roof seals the moisture in and makes the problem worse. We'll check before we recommend it.

Flat Roof Replacement

When a roof has reached the end of its life, patching becomes a monthly expense. Signs it's time to replace:

• Leaks in more than one spot, or leaks that come back after repairs
• Soft or spongy spots when you walk the roof (rotted deck)
• Widespread cracking, blistering, or shrinking membrane
• Two or more roof layers already on the house
• The roof is 20+ years old

What a Top Tier replacement includes:

1. Full tear-off down to the deck, with debris cleared at the end of each day
2. Replacing any rotted deck boards
3. Correcting low spots so water drains to the back of the roof
4. New insulation where needed
5. New roof membrane
6. New flashing at party walls, parapets, chimneys, vents, and skylights, rebuilt to the manufacturer's specs
7. New or rebuilt drain, scupper, and downspout connection
8. 10-year workmanship warranty

Most South Philly rowhome replacements are done in one day. We work on narrow streets every day and plan material drop-off and debris removal around parking and your neighbors. Your estimate will be in writing and itemized before any work starts, and financing is available.

Choosing a Flat Roof Material

	Rubber (EPDM)	Modified bitumen	TPO	Coating (over existing)
What it is	Large rubber sheets, glued or fastened, seams taped	Asphalt-based rolls, torched or self-adhered in layers	White single-ply sheets with heat-welded seams	Liquid silicone or acrylic applied over a sound roof
Typical lifespan	20 to 25+ years	15 to 20 years	20 to 25 years	5 to 15 years, depending on product
Good for	Most rowhomes; easy to repair	Roofs with foot traffic	Keeping the top floor cooler in summer	Extending a roof that's still dry and sound
Watch out for	Seam failure if poorly installed	Torch work near old wood framing needs care	Installer skill matters with seam welds	Doesn't fix wet insulation or rotted deck