Slate Roofing Guide

Photo source: Interlock

Slate Roofing Guide

Overview of Slate Roofing

In the U.S., slate roofing dates back to early colonial times around the early 17th century. It’s been used even longer than that in Europe. Slate is not only an aesthetically pleasing choice for roofing, but it is also one of the most durable roofing materials on the planet.

In addition to all-natural quarried slate, synthetic slate roofing material is also available. Major manufacturers like GAF and CertainTeed offer slate roofing constructed from lightweight polymers and composite materials designed to resemble the look of slate but at a fraction of the cost.

Synthetic slate roofing from GAF

Synthetic slate roofing resembles the real thing. Photo source: DaVinci

Because natural slate is a relatively heavy roofing material, it may not be a suitable choice for all roofing structures. Synthetic slate may be the better option in cases where weight is a major concern. GAF manufactures a slate product that is 100% natural slate but weighs up to 50% less than traditional slate tiles. So, even when weight is a serious concern, it still may be possible to go with a natural slate roofing product.

Whether you prefer the fine-grained crystalline rock that is natural slate or the more cost-effective synthetic slate roofing material available today, there are plenty of options out there to satisfy your needs.

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 to 125 years if installed correctly.

Slate is a quarried material mechanically shaped into roofing tiles. Because it’s an all-natural material, the quality of slate 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 or longer

S2

40 to 75 years

S3

20 to 40 years

Pros and Cons of Slate Roofing

Pros:

  • 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

Cons:

  • One of the most expensive roofing choices
  • Heavy
  • Finding an experienced slate roofing contractor can be challenging in some cases
  • Slate – being a rock material – can shatter from strong impacts
  • Not suitable for low-slope roofing applications

Cost of Slate Roofing

The cost of installing a new slate roof can vary significantly depending upon the complexity of the installation. The prices below depict the average price for tearing off a single layer of roofing material and installing new slate tiles. The slate roof price per square foot can range from as little as $7 up to $13.

Slate Roof Pricing:

City

Cost Includes Tear-Off (Single Layer)/Materials/Installation (2,000 sqft roof)

Chicago

$16,600 - $26,000

Atlanta

$16,000 - $24,300

New York

$17,200 - $27,700

Los Angeles

$16,500 - $25,700

(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 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, resistant to wind (110 mph+) and are Class A fire-rated.

Warranties on Slate Roofing

There are two warranties to consider when working with slate roofing: Manufacturer’s warranty and workmanship warranty. The manufacturer’s warranty protects the product against factory defects. These warranties are typically long-term, ranging from 50-years to lifetime for natural slate products and 20 to 50 years for synthetic slate.

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, you can expect 75 or more years of usable service life. It’s unlikely you’ll ever end up exercising the manufacturer’s warranty.

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.

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 warranty and what isn’t.

Eco-Friendly Roofing Material

Roofing material waste makes up an estimated 5% of all waste entering landfills in the United States. Asphalt shingle roofing waste makes up the majority of this waste since approximately 4 out of 5 homes in the U.S. have asphalt shingle roofs. Shingles are inexpensive and becoming increasingly durable; however, these roofs only last an average of 12 to 17 years before needing to be replaced.

Slate roofs, on the other hand, can last for 75 or more years, or about five times longer than the average shingle roof. This greatly decreases the amount of roofing waste trucked off to landfills.

Slate Roof Maintenance and Repairs

Natural slate roofing requires periodic inspections and basic maintenance. 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.

Slate roofs are repairable in most cases. An experienced slate roofer can replaced individual slate tiles without having to remove a large section of roof. Due to the longevity of slate roofing, it’s almost inevitable that repairs will be necessary at some point.

Sometimes slate roofing repairs aren’t the best option, particularly when a large portion of the roof is damaged. If 20% or more of the roof is damaged, it’s often more cost-effective to replace the entire slate roof rather than repairing the damaged areas, says the U.S. Department of the Interior’s Technical Preservation Services.

Finding a Qualified Slate Roofing Contractor

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 aims to simplifying the process of finding the right contractor for the job.  We list the roofer’s specialties and verify 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 comes from an actual customer or we don't publish it.  Now you can read real reviews from your neighbors to help determine the right roofer for your project.