What Is Asphalt?
Asphalt is a roof covering of overlapping fiberglass-mat shingles surfaced with mineral granules, laid over underlayment, flashing, and drip edge into a water-shedding system. It comes in flat 3-tab and dimensional architectural profiles.
What Is Slate?
Slate is a roof covering of quarried natural-stone tiles set on non-ferrous copper or stainless-steel fasteners over a sound deck. Natural slate is among the longest-lived roof coverings.
Which Roof Suits an Essex County Home, Asphalt Shingles or Natural Slate?
Asphalt shingles are the budget asphalt-mat covering that lasts 20 to 30 years per the InterNACHI chart, while natural slate is the quarried-stone covering that lasts 60 to 150 years; asphalt installs cheaper, slate lasts a homeowner's lifetime.
Asphalt shingles install across northern New Jersey at $5.50 to $9.50 per square foot for 3-tab and $6.50 to $11.00 for architectural, per Josten Roofing's NJ figures, defining the entry tier for an Essex County reroof.
Natural slate installs at $10 to $30 per square foot, roughly $1,500 per square, per NJ roofing guides, and is the highest-priced covering on the historic homes of Montclair, Glen Ridge, and Newark's landmark districts.
Asphalt vs Slate
| Feature | Asphalt | Slate |
|---|---|---|
| Lifespan (InterNACHI chart) | 20–30 years | 60–150 years |
| NJ installed cost | $5.50–$11.00/sq ft | $10–$30/sq ft (~$1,500/square) |
| Material weight | Light (no structural upgrade) | Heavy (structural load reviewed before install) |
| Fasteners required | Standard roofing nails | Non-ferrous copper or stainless (Brief 29) |
| Freeze-thaw resistance | Cracks and curls on lower-grade 3-tab | Stone unaffected; failures are fasteners/flashing — NRCA/NSA |
| Repair method | Patch or section R&R, $360–$1,550 | Tile-by-tile, $50–$300 per slate |
| Replace-the-roof threshold | >25–30% of area damaged | >20% of slates failed (Brief 29) |
| Historic-district fit | Not in-kind on a slate roof | In-kind match (Standard 6) |
Detailed Analysis
How Long Does Each Roof Last, Asphalt or Slate?
Asphalt shingles last 20 to 30 years and natural slate lasts 60 to 150 years, per the InterNACHI Standard Estimated Life Expectancy Chart; the National Slate Association rates ASTM S-1 slate at a 75-year minimum.
Asphalt shingles split by type: 3-tab lasts about 20 years and architectural about 30 years per the InterNACHI chart, with the NRCA noting actual asphalt life varies up to 40% with climate, installation, and maintenance.
Natural slate outlasts its own fasteners and flashing, so failures trace to corroded fasteners or degraded valley flashing rather than the stone, per NPS Preservation Brief 29; individual slates are replaced indefinitely while the deck stays sound.
Which Roof Costs Less to Install and to Repair in NJ?
Asphalt shingles install cheaper in New Jersey at $5.50 to $11.00 per square foot, while natural slate runs $10 to $30 per square foot, roughly $1,500 per square, per Josten Roofing and NJ roofing guides.
Asphalt shingles repair at $360 to $1,550 for minor patch or flashing work per Angi, and a New Jersey roof leak repair runs $400 to $1,000 per HomeAdvisor, since NJ pricing sits about 10 to 15% above the national average.
Natural slate repairs tile-by-tile: a single broken slate replaces for $50 to $300 per HomeGuide, and slate repair averages near $1,400 within a $500 to $2,100 band, because the stone is sounded, flipped, and reset rather than patched.
When Does Damage Force a Full Replacement on Each Roof?
Natural slate reaches replacement when 20% or more of its slates are broken, missing, or sliding, per NPS Preservation Brief 29; asphalt shingles reach it when damage exceeds 25 to 30% of the roof area, per contractor consensus.
Natural slate carries a non-ferrous fastener rule: solid copper or stainless steel nails are specified because plain or galvanized steel rusts out long before the slate, per NPS Preservation Brief 29, and the slate is never walked on or coated to seal moisture.
Asphalt shingles fail through wind-driven granule loss, edge and tab curling, and thermal-shock cracking along the cutouts, per NRCA and InterNACHI guidance, with the 50% rule favoring replacement once one repair approaches half the replacement cost.
How Do Asphalt and Slate Handle the NJ Freeze-Thaw Climate?
Natural slate outlasts its own fasteners and flashing, so New Jersey freeze-thaw failures trace to corroded fasteners and degraded valley flashing rather than the stone, while asphalt shingles crack and curl after years of freeze-thaw, per NRCA and InterNACHI guidance.
Natural slate weathers to surface sugaring on lower-grade stone rather than structural cracking, per NRCA and the National Slate Association, so a sound slate field stays intact while its non-ferrous fasteners and valley flashing remain the components that age.
Asphalt shingles depend on an ice-and-water shield at the eaves, required at eaves with an ice-dam history and extending at least 24 inches inside the exterior wall line, per IRC R905.1.2 as enforced under the NJ Uniform Construction Code (N.J.A.C. 5:23), to block the ice-dam backup that freeze-thaw drives under the field shingles.
Which Roof Fits a Historic vs Budget-Conscious NJ Home?
Natural slate fits a historic or slate-clad home as a multi-generational roof, while asphalt shingles fit a budget-conscious or near-term-sale home, installing at one-third to one-half slate's per-square-foot cost.
Natural slate is the in-kind material on a contributing structure in a designated local historic district, where Standard 6 of the Secretary of the Interior's Standards directs that a deteriorated slate roof be repaired or matched in kind rather than swapped for asphalt.
Asphalt shingles carry the weight advantage on the residential framing question: asphalt is a light covering that loads any properly sheathed roof, while natural slate is a heavy quarried-stone covering whose structural load is reviewed before installation rather than assumed.
Where Does Each Roof Make Sense on a Commercial Building?
Natural slate suits image-driven commercial buildings such as law offices and historic storefronts, while asphalt shingles suit functional buildings where pure return on investment governs the steep-slope sections.
Natural slate on a landmark commercial property in Newark's James Street Commons or Lincoln Park district triggers a Certificate of Appropriateness from the Historic Preservation Commission, per N.J.S.A. 40:55D-107, before a roofing-material change.
Asphalt shingles cover steep-slope commercial sections economically, though flat commercial roofs use single-ply membrane systems rather than either steep-slope material, matching the low-slope geometry.
Our Verdict
Asphalt shingles win on cost; natural slate wins on multi-generational lifespan
Asphalt shingles over natural slate when the ownership horizon is under 15 years or the budget caps near the $10,000 to $11,000 national asphalt-replacement benchmark, since asphalt installs at $5.50 to $11.00 per square foot.
Natural slate over asphalt shingles when the home already carries slate or sits in a designated local historic district, where Standard 6 of the Secretary of the Interior's Standards directs an in-kind match rather than an asphalt substitute.
Not sure which is right for you? Call for a free consultation.