By Fern Goddard, Roofing Guides EditorUpdated September 2026
In 2026, published Philadelphia figures put a typical residential roof replacement at $5,192 to $10,986, a rowhome architectural shingle roof of 10 to 15 squares at $5,500 to $10,000, and rowhome flat roofs at $6 to $11 per square foot installed. Extra layers, rotted decking, permits and access move a quote within those ranges.
The Published Ranges, Roof by Roof
Several 2026 cost guides cover Philadelphia specifically. Across typical homes, the range for a full replacement runs $5,192 to $10,986. For the most common pitched job, a rowhome or twin with architectural shingles covering 10 to 15 squares, published figures run $5,500 to $10,000.
Flat roofs are priced by area. A recent Philadelphia guide puts rowhome flat roofs at $6 to $11 per square foot installed, with EPDM at $6 to $9 per square foot and TPO at $7 to $10 per square foot. Since most rowhome roofs cover roughly 800 to 1,400 square feet, the membrane choice changes the total by a few thousand dollars at most.
Historic slate is its own category: full slate roof work in the city is published at $30,000 to $50,000 and up, which is why slate repair is almost always priced first.
Layers and Decking: The Two Biggest Swings
Philadelphia requires a full tear-off once a roof carries two layers, and older houses often carry more. Published figures add $1,000 to $2,000 for an extra layer on a shingle job and $1.50 to $3 per square foot for a full tear-off on a flat roof.
The deck is the unknown until the old roof is off. Soft or rotted boards have to be replaced before anything new goes down, and published sheathing replacement runs $2 to $7 per square foot. A good estimate names a per-sheet or per-foot price for decking so the change is not a surprise. See our roof replacement page for what a full job includes.
Permits, Access and the City Premium
A replacement needs a permit from Licenses and Inspections, published at $150 to $350. City jobs also cost more than suburban ones for practical reasons: rowhome access, parking for a dumpster or truck, disposal, and materials carried up three stories.
Rear additions and porch roofs add their own line. A rear flat section added to a shingle replacement is published at $2,000 to $4,000, and it is worth doing at the same time, since the joint between old and new roofs is where leaks start.
How to Compare Two Estimates
Put the estimates side by side and check the scope, not just the total. Does each include tear-off to the deck, and at how many layers? Is decking priced per sheet? Is underlayment across the whole roof, with ice and water barrier at the eaves and valleys? Are flashing, pipe boots and drip edge new or reused? Is the permit included?
A lower number that reuses old flashing, skips ice barrier or leaves the permit to you is not cheaper; it is a different job. Ask each roofer to write their scope in the same terms so you can see what you are actually buying.
Want a measured number for your roof?
Call and we measure it, count the layers and price it in writing.
A Worked Example on a Rowhome
Take a rowhome with a 1,000 square foot flat roof and two old layers on it. At the published rowhome range of $6 to $11 per square foot installed, the new roof lands somewhere around $6,000 to $11,000. Because two layers are already on, a full tear-off is required, and at the published $1.50 to $3 per square foot that adds roughly $1,500 to $3,000. The permit adds $150 to $350.
Where the job lands inside those ranges depends on the membrane, how much decking is soft, how the parapets and the neighbor's roof are tied in, and access. This is an illustration built from published ranges, not a quote, but it shows why the layer count and the deck matter as much as the membrane.
What Should Be Written on Your Estimate
A good estimate reads like a scope, not a single number. Look for these lines:
- Tear-off to the deck, with the number of layers stated
- Decking replacement priced per sheet or per square foot
- Underlayment or insulation and cover board across the whole roof
- Ice and water barrier at eaves and valleys on pitched roofs
- New flashing at walls, chimneys and parapets, plus new pipe boots
- Drip edge, coping or edge metal
- Permit, dumpster and cleanup
Where Repair Still Makes Sense
Not every old roof needs replacing. One failed boot, a flashing joint or a few storm-damaged shingles on an otherwise sound roof are repairs, and published Philadelphia leak repairs run $300 to $3,500. The case for replacement is leaks in several places, brittle material across the roof, soft decking, or a second layer already on. Our repair or replace guide walks through that decision.
Common Questions
Usually because the scopes differ: layers, decking, underlayment, flashing and permits. Compare line by line.
Per job, rowhome flat roofs are often similar to or below a shingle roof, because the roof area is small.
Published figures put the L&I permit at $150 to $350, a small part of the total.
If they are old or sagging, yes. New drip edge and gutters work best installed together.
Ask each contractor what they offer; financing terms vary widely and are separate from the roof price.
Material prices move, so most written estimates carry an expiry date. Check it before you sign.