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Slate to asphalt · the main question

Can You Replace a Slate Roof with Asphalt Shingles?

Usually yes. The exceptions are historic properties, where a commission or board decides, and roofs where the slate still has decades left.

Ask about your slate roof How estimates work
  • Answer first, then the detail
  • Philadelphia, Cheltenham, Lower Merion, Narberth
  • Sources checked Oct 29, 2026

Can you replace a slate roof with asphalt shingles?

Yes, in most cases you can replace a slate roof with asphalt shingles. The slate is stripped, the deck is repaired and sheathed, and new underlayment, flashing and shingles go on. If the house is on a historic register or inside a local historic district, a commission or review board has to approve the change first.

Workers stripping old shingles from a roof
Illustrative stock photo.

When does a slate-to-asphalt switch need historic approval first?

It needs approval first when the house is individually listed or inside a local historic district. In Philadelphia that is the Philadelphia Historical Commission; in Cheltenham's La Mott and Wyncote districts, the township's BHAR; in Lower Merion's districts, a Certificate of Appropriateness; in Narberth, only certain roof changes need one.

In Philadelphia, staff can approve slate replacement without a hearing when the slate is deteriorated enough to need replacing and the substitute closely matches the color and shape of the slate, except on mansards, turrets and other character-defining features (Rules & Regulations §6.10.c(4)). Our historic approvals guide covers each municipality with citations.

What changes on the roof when slate comes off

  • Weight. Slate is far heavier than asphalt, so the rafters carry less afterward. Philadelphia's EZ standard excludes jobs that increase gravity load by more than 5%, which a slate-to-asphalt job does not.
  • The deck. Slate is often nailed to boards that are fine for slate but too gapped or too brittle for shingle nails. Expect sheathing over the boards or board replacement in places.
  • Tear-off. Philadelphia's EZ standard requires a full tear-off of slate; you can't shingle over it.
  • Flashing. Slate roofs often carry copper or terne flashing built for slate. It is replaced with flashing sized for shingles, and chimney counter-flashing is reset.
  • Look and pitch. Asphalt is allowed only on slopes of 2:12 or steeper under the EZ standard; most slate roofs here are far steeper. The edge line and ridge look thinner than slate, which is why dark, slate-toned shingles are the usual pick.
  • Lifespan. An asphalt roof will not last as long as good slate did. That is the trade for a lower upfront cost.
Close-up of a slate roof laid in overlapping rows
Illustrative stock photo.

When should you not switch a slate roof to asphalt?

You should not switch when the slate itself is sound and the leaks come from flashing, nails or a few broken pieces. The National Park Service says a roof with fewer than about 20% damaged slates should be evaluated for repair. In that case a slate specialist, not an asphalt roofer, is the right call.

We will tell you that at the inspection. Our fix-or-replace guide shows the checks, and the cost guide compares the numbers.

If you go ahead with us

  • A free inspection, including the attic side of the deck.
  • A written estimate that separates slate removal, deck work, flashing and shingles.
  • The historic approval application prepared with you where one is needed, before the building permit.
  • 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.

Slate-to-asphalt questions

Will asphalt shingles look out of place on a stone house that had slate?
They look different up close, mostly at the edges and ridge. Dark, heavy architectural shingles in a slate gray or black read closest from the street. On historic properties in Philadelphia the color and shape match is part of what staff weigh before approving.
Can the old slate be saved or sold?
Sometimes. Sound slates have salvage value and slate specialists use them for matching other roofs. Whether yours are worth saving depends on type and condition, which the inspection notes. Removal costs more when slates are taken off carefully for reuse.
Is it legal to take slate off a house that isn't historic?
Yes. Outside historic designations, a slate-to-asphalt job is an ordinary re-roof that needs the normal building permit. The permit office may still want product specifications and, in Philadelphia, follows the EZ re-roofing standard's tear-off and decking rules.

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.

Is your slate roof ready to go?

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.

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