Dating back to the early 17th century, slate roofing is one of the most beautiful and durable roofing materials around.
Learn more about this century-old roofing material with the help of our guide to commercial roofing. Below, we outline the most common types of slate roofing available today, the advantages and disadvantages to a slate roof, and the cost of installation and repair.
On this page, we discuss...
- Thickness & Weight
- Expected Lifespan
- Materials Comparison
- Pros & Cons
- Maintenance & Repairs
- Find the Right Contractor
Slate Roofing Thickness & Weight
Genuine roofing slates are split by hand using a hammer and chisel, revealing a naturally uneven surface that varies slightly in thickness.
These thicknesses are grouped into different groups, which can vary in weight:
|Slate Thickness||Average Weight|
|3/16" - 1/4"||800 lbs per square|
|1/4" - 3/8"||1,000 lbs per square|
|3/8" - 1/2"||1,400 lbs per square|
|1/2" - 3/4"||2,500 lbs per square|
|3/4" to 1"||3,000 lbs per square|
Expected Lifespan of Slate Roofs
If you’re looking for a long-lasting roofing material, slate should definitely be at the top of your list.
There are documented cases of slate roofs in Europe that have withstood the elements for more than two centuries. A good-quality natural slate roof can be expected to last 60 - 125 years if installed correctly.
Because slate is an all-natural material, its quality varies. The ASTM grades slate roofing material on a scale ranging from S1 to S3. S1-grade slate is the highest quality and most durable choice.
|Grade||Expected Lifespan / Durability|
|S1||75 + years|
|S2||40 - 75 years|
|S3||20 - 40 years|
Slate Roofing Materials Comparison
Historically, slate roofs have always been extremely heavy and quite expensive, but that's no longer the case.
Slate is naturally heavy, but modern manufacturers are finding ways around all this unnecessary weight. For example, GAF's TruSlate is made of genuine slate; however, instead of overlapping slate-on-slate—as is traditionally done—they've used a high-tech waterproofing material to help lighten the load.
There are other slate roofing options available, too, so be sure to compare your options before committing.
|Traditional Slate||GAF Truslate||Synthetic Slate||Slate-look Asphalt|
|Easy to install||No||Yes||Yes||Yes|
|Easy to repair/replace||No||Yes||No||No|
|Made from real slate||Yes||Yes||No||No|
|Does not warp or curl||Yes||Yes||No||No|
|Individual slates can be adjusted after installation||No||Yes||No||No|
|Realistic slate appearance||Yes||Yes||No||Some|
|Lifetime limited warranty available on roofing system||No||Yes||No||Yes|
Slate Roofing Pros & Cons
Advantages of a Slate Roof
- Highly-desirable appearance
- Available as a natural slate or composite slate
- Produces a one-of-a-kind roof
- Fire resistant
- Eco-friendly roofing choice
- Very low maintenance
- Weather resistant
- Can last 75+ years
Disadvantages of a Slate Roof
- One of the most expensive roofing choices
- Finding an experienced slate roofing contractor can be challenging in some cases
- Natural material can shatter from strong impacts
- Not suitable for commercial or low-slope roofing applications
Slate Roofing Cost
Natural slate roofing typically costs between $7 and $13 per square foot, but can reach as high as $25 per square foot installed.
The cost of installing a new, natural slate roof can vary significantly, and it depends on a number of factors, like the size and complexity of your roof, your geographic location, the slate material you're using, and more.
The prices below depict the average price for tearing off a single layer of roofing material and installing new slate tiles in various locations across the United States.
|Chicago, IL||2,000 sq. ft.||$17,000 - $26,500|
|Atlanta, GA||2,000 sq. ft.||$16,500 - $25,000|
|New York City, NY||2,000 sq. ft.||$17,500 - $28,000|
|Los Angeles, CA||2,000 sq. ft.||$17,000 - $26,000|
(This pricing does not include costs associated with installing added ventilation or gutters. Contact your local slate roofing contractor for a customized quote.)
Synthetic slate roofing tiles may cost less, but they vary in quality and durability. The best quality synthetic slate roofing products have a thickness of ½-inch or more, carry a 50+ year warranty, are UL rated for impact resistance, are resistant to wind (110 mph+), and are Class A fire-rated.
Slate Roof Maintenance and Repairs
Natural slate roofing requires basic periodic inspections and minimal maintenance.
Due to the longevity of slate roofing, it’s almost inevitable that repairs will be necessary at some point. However, slate roofs are almost always repairable.
It’s important to have cracked or missing slate tiles repaired as soon as possible. This helps limit water damage and potential damage to the surrounding roof. Luckily, an experienced slate roofer can replace individual slate tiles without having to remove a large section of the roof.
Warranties on Slate Roofing
There are two warranties to consider when working with slate roofing: manufacturer’s warranty and workmanship warranty.
Manufacturers' warranties protect against factory defects and are typically long-term, ranging from 50 years to a lifetime for natural slate products and 20 - 50 years for synthetic slate products.
It’s important to never purchase roofing based exclusively on the length of its manufacturer’s warranty. If you go with an S1 graded slate, it’s unlikely you’ll ever end up exercising the manufacturer’s warranty since you can expect to get 75+ years of usable service life.
In addition to a manufacturer’s warranty, most roofing companies offer workmanship warranties designed to protect your roof against damage directly related to the installation. Some workmanship warranties may also contain “leak-free guarantees” or similar language. Always read the fine print to make sure you understand what’s covered under your warranty and what isn’t.
The roofer’s expertise and knowledge of slate roofing is far and away the most important factor to consider.
An experienced slate roofing contractor can recommend the optimal roofing material for your installation based on the local weather patterns and their experience installing and repairing a particular slate product.
It's challenging to find an experienced slate roofing contractor due to the fact it’s such a specialized type of roofing product and a high level of skill is required to get the job done right.
Hometown Roofing Contractors aims to simplify the process of finding the right roofing contractor for the job. We list the roofers' specialties and verified credentials, so you can find a qualified slate roofer quickly and efficiently.
We also publish roofing contractor reviews, ratings, and project costs. Hometown verifies every review to ensure that it comes from an actual customer, or we don't publish it.