Slate to asphalt · materials
Synthetic Slate or Natural Slate: Which Is Better?
A neutral comparison of the three materials owners of slate-roofed houses weigh. We put on asphalt only, so we have no stake in which slate you pick.
- Natural slate, synthetic slate, asphalt
- Historic approval wording quoted
- Not a quote
Is synthetic slate better than natural slate?
Natural slate is better for lifespan and for historic approval; synthetic slate is lighter and usually cheaper upfront. The National Park Service calls artificial slate not recommended for restoration work and notes its total initial cost is only marginally less, because tear-off, flashing and labor cost about the same.
For many owners the real choice is between keeping natural slate and going to asphalt, with synthetic as a middle option. The table below sets them side by side.
Natural slate, synthetic slate and asphalt compared
| Natural slate | Synthetic slate | Architectural asphalt | |
|---|---|---|---|
| Published cost (third-party) | $15.50–$31 per sq ft (Angi, Philadelphia) | $10.25–$15.50 per sq ft (Angi, Philadelphia) | $5.30–$7.42 per sq ft (RoofVista, PA) |
| Expected life | About 60 to 200 years by stone type (NPS) | Varies by product; check the maker's terms | Shorter than slate; varies by product |
| Weight | Heaviest | Lighter than slate | Lightest |
| Philadelphia staff approval for slate replacement | Matches by definition | Possible if it closely matches color and shape | Possible if it closely matches color and shape |
| Who puts it on | Slate specialist | Roofer trained on that product | Asphalt roofer (our trade) |
These are published third-party estimates and public fee schedules, dated where the publisher dates them. Not a quote; your price comes after a free inspection.
Will a historic commission accept synthetic slate or asphalt?
In Philadelphia, staff can approve a substitute for deteriorated slate if it closely approximates the color and shape of the historic slate, except on mansards, turrets and other character-defining features. That standard applies to synthetic slate and asphalt alike. In Lower Merion districts the board favors matching material, texture and color.
Approval is decided case by case, so a product sample and dated photos of the roof's condition help any application. Our historic approvals guide quotes each rule.
Where each one makes sense
- Natural slate when the house is a landmark, the roof is a defining feature such as a mansard or turret, or you plan to stay for generations.
- Synthetic slate when you want a slate look with less weight and the reviewing body has accepted the product.
- Asphalt when the slate has failed, the budget is the deciding factor and the review body, if any, approves a slate-toned shingle. That is the job we do.
Material questions
Does synthetic slate cost less than natural slate overall?
Do you put on synthetic slate?
Sources and checked date
- National Park Service, Preservation Brief 29 (Levine, 1993) artificial slate and lifespans
- Philadelphia Historical Commission Rules & Regulations, §6.10.c(4) color and shape standard
- Lower Merion Township Code, Chapter 88, §88-9
- Angi, How much does a slate roof cost in Philadelphia (updated Oct 5, 2026) accessed Oct 29, 2026
- RoofVista, Historic slate roofing in Pennsylvania (Mar 26, 2026) accessed Oct 29, 2026
- Adilay Roofing, Philadelphia slate cost guide (Sept 20, 2026) accessed Oct 29, 2026
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.
Weighing your options? Ask us
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.