Most slate roofs cost $4,389 to $22,377, with a reported average of $13,348, according to HomeAdvisor's survey of its customers. That range covers every kind of "slate", including synthetic and metal look-alikes. Natural slate is the costly end: $20 to $30 a square foot installed, according to HomeAdvisor. Fixr, another cost site, reports far higher totals for natural slate, $20,000 to $60,000. What you get for that price is a roof that can last a century or more if the slate is good, the fasteners and flashing are right, and a slater who knows the material looks after it.
What a slate roof costs
| Source | Typical total | Average | Per square foot, installed |
|---|---|---|---|
| HomeAdvisor, updated June 19, 2026 | $4,389 to $22,377 | $13,348 | $20 to $30 for natural slate |
| Fixr, updated January 21, 2026 | $20,000 to $60,000 | $40,000 | $9 to $30 across all types; about $20 on average |
The two sources measure different things. HomeAdvisor averages what its customers reported paying, for jobs of every size and every slate type. Fixr prices a set roof size in natural slate. For a real roof covered in natural stone, the Fixr figures are the closer guide; HomeAdvisor's lower totals include cheaper look-alike products.
Price by slate type, per square foot installed:
| Type | HomeAdvisor | Fixr |
|---|---|---|
| Natural slate, hard | $20 to $30 (natural, not split by hardness) | $20 to $30 |
| Natural slate, soft | as above | $15 to $20 |
| Synthetic slate | $10 to $15 | $9 to $15 |
| Hybrid slate | not given | $10 to $18 |
| Concrete "slate" | $10 to $20 | not given |
| Bituminous "slate" | $10 to $15 | not given |
| Metal "slate" | $15 to $25 | not given |
Our guides to synthetic roofing and to roofing materials compare the look-alikes with the real stone.
What else goes on a slate estimate
- Labor. HomeAdvisor puts it at 40% to 50% of the total, and Fixr at 40% to 60%. HomeAdvisor says one square of natural slate (100 square feet) takes 10 to 12 hours to lay. The National Park Service's guidance on slate roofs gives a similar pace: a slater and a helper cover about two to three squares a day on a clear, open roof, and below one a day where chimneys, dormers and valleys crowd it.
- Removing the old roof. HomeAdvisor gives $1,000 to $5,000; Fixr gives $50 to $150 per square.
- Strengthening the frame, if needed. Both sites put it at $1,000 to $10,000.
- Upkeep. Fixr suggests an annual inspection at about $250.
Ask each roofer to price the slate by its grade and thickness, the copper or stainless nails, the flashing metal and weight, and any sheathing replacement as separate lines. Our guide to comparing roofing estimates shows how to line them up.
How long slate lasts depends on its grade
Slate is not one material. Its life depends mostly on how much water the stone absorbs and how well it resists weathering, which varies from one quarry to the next.
ASTM C406, the standard specification for roofing slate, sorts it into three grades after laboratory tests of absorption, weather resistance and strength. InterNACHI, the home inspectors' association, gives the service life of each:
| ASTM C406 grade | Expected service life |
|---|---|
| S1 | more than 75 years |
| S2 | 40 to 75 years |
| S3 | 20 to 40 years |
Other published figures:
- InterNACHI's life expectancy chart: 60 to 150 years for slate, and InterNACHI adds that S1 slate may last from 75 to 200 years or more.
- The National Park Service: 60 to 125 years or longer for a properly installed slate roof, depending on the slate, the shape of the roof and the climate; some have lasted more than 200 years.
- HomeAdvisor: 100 to 200 years for natural slate and 50 to 125 years for soft slate.
- Fixr: up to 200 years for hard slate and 75 to 100 years for soft.
- The National Slate Association, the trade group: a good-quality slate roof lasts about 75 years on average, some much longer.
Ask for the ASTM C406 grade of the exact slate in writing. A cheap slate can be a short-lived one.
Weight and your roof frame
Slate is heavy, and its weight rises with its thickness. One slate quarry publishes these weights for a square of slate laid with a 3-inch headlap:
| Slate thickness | Pounds per square |
|---|---|
| 3/16 inch | 700 |
| 1/4 inch | 935 |
| 3/8 inch | 1,405 |
| 1/2 inch | 1,870 |
| 3/4 to 1 inch | 3,275 |
The same quarry says 1/4 to 3/8 inch is the most common thickness. Fixr gives 1,000 to 2,000 pounds per square, and InterNACHI says a slate roof can weigh up to 8,000 pounds per square, with 3,500 pounds already counted as heavy. For comparison, one major maker's architectural asphalt shingle weighs 211 to 225 pounds per square.
What that means for your house:
- A roof framed for shingles may need strengthening for slate. Budget for a structural check before you commit.
- The deck matters. InterNACHI says slate needs sheathing at least 3/4 inch thick; 1/2-inch sheathing is not suitable and can lead to broken slates.
- Slope matters. InterNACHI says modern codes require a slope of at least 4 in 12 for slate, and a waterproof underlayment below that.
- When a slate roof is replaced, the old slate comes off first. The Park Service says to remove it so the roof timbers are not overloaded, and to have an engineer who knows older buildings look at any rafters that sag, crack or twist.
Repair or replace a slate roof
Slate often outlives what holds it on. The Park Service and InterNACHI point to three common causes of failure that are not the slate itself:
- Rusting nails. Plain steel and galvanized nails usually rust out long before good slate wears out. Many slates sliding out of place can mean the nails have failed while the stone is still sound.
- Worn flashing. Metal flashing often wears out before the slate does, and a pinhole can let in a lot of water.
- Old underlayment. InterNACHI notes that felt underlayment loses its oils and breaks down over time.
The 20% guideline. The Park Service's rule of thumb: if fewer than about 20% of the slates on a roof or a slope are broken, cracked, missing or sliding, and the roof is otherwise sound, evaluate it for repair. At 20% or more, replacing the roof is usually cheaper than repairing it slate by slate, especially on an old roof, because even a skilled slater breaks a few neighboring slates while working.
Other points from the same guidance:
- Repair one slope at a time if you can. Slate often weathers unevenly, so one slope may need replacing while the others can be repaired, spreading the cost over years.
- Test the slate. Sound slate gives a full, deep sound when tapped and does not crack under firm hand pressure; weak slate gives a dull thud and feels brittle.
- Salvage what you can. When the nails or flashing failed rather than the slate, sound slates can be taken off and laid again, and spares kept for future repairs.
- Do not seal slate with mastic. Roofing cement works at first, then hardens and cracks, makes later repairs harder, and speeds up corrosion of the flashing.
What repairs cost. HomeAdvisor's average slate repair is $1,800, the highest of any material it lists. Fixr puts slate repairs at $300 to $1,600. A broken slate is usually pulled with a slate ripper and a matching new or salvaged slate slid in, held by one nail with a copper strip over it, or by a hook or strap. Our roof repair cost guide compares repairs across materials, and our guide to whether to repair or replace a roof covers the decision for any roof.
Finding a slate specialist
Laying and repairing slate is a separate skill from shingle roofing. The Park Service says slate installation and repair should be left only to experienced slaters, and the National Slate Association says hiring a specialist helps ensure you have the right team. Both slate trade groups keep member directories: the National Slate Association and the Slate Roofing Contractors Association, which also publishes its installation guidelines free to the public.
Questions to ask a roofer about slate:
- How many slate roofs have you installed or repaired, and can I see some?
- What grade and thickness of slate will you use, and can you show its ASTM C406 test results?
- What nails will you use? The Park Service calls for copper or stainless steel.
- What metal and weight will the flashing be?
- How will your crew move on the roof without breaking slate?
- Will you salvage sound slate, and will you leave spares?
Check any roofer's license and insurance as well; our guide to what to check before you hire a contractor covers the basics, and questions to ask a roofer has more.
Keeping people off the roof
Slate breaks underfoot. The Park Service advises keeping foot traffic off a slate roof, inspecting it from the ground with binoculars or from a lift, and having anyone who must go up, such as a chimney sweep or painter, work from a ladder hooked over the ridge. If someone has to step on the slate, soft-soled shoes and the lower middle of each exposed slate are the least risky. The same guidance suggests an inspection every year and after severe storms, and cleaning the gutters at least twice in the fall and once in spring.
Frequently asked questions
Is a slate roof worth the cost?
It can be, on a house you plan to keep and a frame that can carry it. Good slate is rated to last more than 75 years, several times the life of an asphalt roof, and a well-kept roof can often be repaired instead of replaced. The high price and weight are the reasons against it.
How long does a slate roof last?
It depends on the slate's grade. ASTM C406 grade S1 is rated for more than 75 years, S2 for 40 to 75 and S3 for 20 to 40. InterNACHI's chart gives slate 60 to 150 years overall.
Can a slate roof be repaired, or must it be replaced?
Usually repaired if fewer than about 20% of the slates are damaged, according to National Park Service guidance. Leaks often come from worn flashing or rusted nails, not the slate.
How much does a slate roof weigh?
One quarry lists 700 pounds per square for 3/16-inch slate and 1,405 pounds for 3/8-inch. One maker's architectural asphalt shingle weighs 211 to 225. Have your roof frame checked before you choose slate.
Is synthetic slate a good substitute?
It costs less per square foot, $10 to $15 installed according to HomeAdvisor, and weighs less. The Park Service notes that labor, flashing and tear-off cost the same either way, so the total saving is smaller than the material price suggests. Lifespan estimates for synthetic slate vary widely by source.
How we got these numbers
HomeAnvil does not yet publish price data of its own. Every figure on this page comes from a published source, read on September 26, 2026:
- HomeAdvisor, slate roof cost, updated June 19, 2026: the typical and average totals, prices by slate type, labor share and hours per square, removal, reinforcement and lifespans. HomeAdvisor says its figures come from a survey of its customers and other published research.
- HomeAdvisor, roof repair cost, updated June 19, 2026: the average slate repair.
- Fixr, slate roof installation cost, updated January 21, 2026: its totals, prices by type, labor share, removal, reinforcement, inspection, repair range, weight and lifespans.
- National Park Service, Preservation Brief 29, The Repair, Replacement, and Maintenance of Historic Slate Roofs, by Jeffrey S. Levine: lifespan, causes of failure, the 20% guideline, repair methods, salvage, installation pace, walking on slate, inspection and gutter cleaning.
- InterNACHI, Mastering Roof Inspections: Slate Roofs, part 2 (ASTM C406 grades and service life) and part 5 (weight, sheathing, slope and felt underlayment).
- InterNACHI, standard estimated life expectancy chart: slate life.
- North Country Slate, thickness and weights: weight per square by thickness. We cite it as a quarry's published figures, not as a recommendation.
- National Slate Association, for homeowners: average lifespan and hiring a specialist. Slate Roofing Contractors Association, home page: its directory and free installation guidelines. Both are slate trade groups.
- CertainTeed, Landmark shingle data sheet: the architectural shingle weight used for comparison.
We will update this page when these sources publish new figures, and the date above will say when.
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