Asphalt vs Metal vs Slate: The Real Numbers for a Westchester Home

A 50-year cost comparison for a 2,400 sf colonial — including replacement cycles, resale lift, and the hidden cost of scaffolding.

Every salesperson will tell you their material is the best. The honest answer is: it depends on how long you plan to own the house.

Architectural asphalt shingles average $7.50–$11 per square foot installed in Westchester in 2026. Warrantied 30 years but realistically delivering 22–25 in our freeze-thaw climate. Call it a 24-year lifespan.

Standing-seam metal lands at $15–$22 per square foot. Warranty 40–50 years, delivers close to it. The install is twice as complicated — most of the cost is labor, not material, and most of that labor is at the eaves and valleys.

Slate is $28–$42, and a properly-installed slate roof on a well-built deck will outlast the family. The catch is that every future repair costs 3x what an asphalt repair does because the crew that can do it is harder to find.

Amortized over 50 years including one asphalt replacement versus zero slate replacements, slate wins by roughly 15% in total cost — but only if you plan to own the house long enough to benefit. Selling in year 12? Asphalt is the better financial move.

The part most quotes leave out is scaffolding. For a 2,400 sf colonial in the Rivertowns, scaffolding adds $4,000–$9,000 depending on pitch and access. That cost applies once per replacement — which is why the lifespan math matters more than the per-square-foot math.

Our rule of thumb: architectural asphalt if the house will be sold within 15 years. Metal if the owners plan to stay and care about energy performance. Slate only on homes that were built for it — we will not put slate on a deck that cannot carry it.