Roof replacement · pre-1940 houses

Asphalt Shingle Roof Replacement on Older Houses

A new asphalt roof on a prewar house is mostly about what sits under the shingles. Here is what we check, what we replace and what the permit offices expect.

  • Full tear-off, never a layover on an older roof
  • Deck boards repaired or replaced as found
  • 15-year workmanship warranty on asphalt shingle replacements

What does an asphalt roof replacement on a pre-1940 house include?

It includes a full tear-off to the deck, repair or replacement of rotted or gapped deck boards, new underlayment, drip edge, new flashing at chimneys, walls and valleys, ventilation corrections and asphalt shingles. On older houses the deck and flashing work is where most of the variation in price comes from.

Roofing crew tearing off and replacing asphalt shingles on a one-story house
Illustrative stock photo.

What we look for on an older roof

  • Board decking. Prewar roofs sit on 1x boards, sometimes with gaps. Asphalt needs a solid nailing surface, so gaps are sheathed over and soft boards are replaced.
  • Layers. A second or third covering hides deck damage and adds weight. Philadelphia's EZ re-roofing standard requires a full tear-off where there are two or more coverings.
  • Chimneys. Many chimneys here were flashed into mortar joints that have since eroded. New step and counter flashing is part of our scope, and we flag masonry that needs a mason first.
  • Built-in gutters. Box gutters hidden in the roof edge are common on houses from this era. We note their condition at the inspection, because a new roof over a leaking box gutter still leaks.
  • Ventilation. Attics on old houses were rarely vented for a modern roof. We size intake and exhaust so the new shingles aren't cooked from below.
Brick chimney with a metal cap rising from a red metal roof
Illustrative stock photo.

Does a roof replacement need a permit here?

Yes, in every municipality we serve. Philadelphia issues re-roofing permits through eCLIPSE, Cheltenham and Jenkintown require permits for roofing, and Narberth has a roofing permit form. Properties under historic protection need approval before the permit. We pull the permit as part of the job and list it on the estimate.

The details, fees and sources for each municipality are on our roof rules data page, with a CSV you can download.

Shingles we use

We install architectural asphalt shingles from GAF and other major manufacturers, chosen for the house and the budget. Philadelphia's EZ standard sets the minimum product test ratings and a Class B fire rating, and requires manufacturer installation instructions with the application, so the product sheet goes in with the permit.

For houses coming off slate, darker charcoal and weathered-slate colors are usually the best visual match, and in Philadelphia that match is part of what the Historical Commission staff weigh. See synthetic vs. natural slate for the higher-end options people ask about.

Close-up of brown asphalt roof shingles
Illustrative stock photo.

What the estimate spells out

  • Tear-off and disposal, by layer.
  • Deck boards to replace, and sheathing over gaps, as separate lines.
  • Flashing at each chimney, wall and valley.
  • Ventilation changes, if any.
  • Which permit applies and whether a historic approval comes first.
  • Asphalt shingle roof replacements, including slate-to-asphalt conversions, come with a 15-year workmanship warranty.
  • Financing is available, including a 12-month no-interest option. Subject to credit approval. Terms vary; ask for details.

Roof replacement questions

Can new shingles go over the old roof on an older house?
We don't do layovers on prewar houses. A second layer hides the deck, adds weight to old rafters and shortens the new roof's life. Philadelphia's EZ re-roofing standard also requires a full tear-off when a roof already has two or more coverings or is damaged.
How long does a roof replacement take on an older house?
Most single-family houses take a few working days once materials and the permit are in hand. Deck replacement, chimney work and weather add time. The written estimate gives a working-day range for your house after the inspection.

Sources and checked date

Last checked 2026-10-29.

Rules change. Confirm with the city, township or borough permit office before you rely on any permit or historic-district detail here.

Get a roof replacement estimate

Tell us where the house is, how old the roof is and what it is doing. If you have photos, say so and we will ask for them by email. Outside our core area? Send the form and ask.

We answer form requests Monday to Friday, 9am to 5pm. There is no phone line, so the whole conversation stays in writing.

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