Slate Roofing Manufacturers List & Website Directory

By Roof Online Staff • Last updated April 18, 2024

To learn more about slate roofing, see our articles:

Roofing Slate Colors and Where They Come From

See Synthetic Composite Shingle Manufacturers for synthetic slate manufacturers.

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Close up of roofing slates on a slate roof. — Close-up of a slate roof (image courtesy American Slate Company)

Natural slate has been used as a roofing material for well over a thousand years. Slate forms from the metamorphosis of sedimentary rock under high pressure and temperature conditions. Its geological precursor is called shale, and the end product of these geological processes is a dense, durable, and naturally water-resistant stone that can be quarried, split, and processed into an excellent roofing material.

Sources of Natural Roofing Slates

North American Slates: Quarried primarily in the northeastern United States and parts of eastern Canada, these slates are known for their long service life and come in a very wide variety of colors and grades. Gray, green, black, purple, mottled, and even the very uncommon red slate (which can look somewhat like terra cotta) are among the available colors.
Welsh Slates: Northern Wales is one of the very first known centers of slate production, delivering very high quality slate continuously since the Middle Ages. Varieties of Welsh slate are particularly noted for their color and durability, They are often considered among the best in the world.
Spanish Slates: Around 90% of the roofing slate used in Europe today comes from Spain. Spanish slate is known for its consistency and respectable performance. Spanish slates tend to cost less than slate produced elsewhere in Europe.
Brazilian Slates: Brazil is a more recent entrant in the slate market. Brazilian slates are recognized for their affordability and variety of colors, including grays and greens, and are often used in both roofing and flooring. You need to be a little more careful when vetting Brazilian roofing slate producers.
Chinese Slate: China has been supplying slate to the rest of the world since around the year 2000. Chinese slate can be high-quality like slate from anywhere else, but it’s important to find a supplier with a very good reputation before you buy. You want to make sure the grade and type of slate has been verified by a trusted, reputable middle man. There have been issues in the past.

Each type of slate has its own distinct qualities that relate to the place it came from (kind of like wine). These local variables affect its appearance, expected service life, and its suitability for different climates and architectural styles.

Important Considerations Before Buying

Quality: The quality of roofing slate can vary significantly, which affects its lifespan and appearance. In the United States, you should look for S1-grade hard slate. High-quality slate should not have any iron pyrite (fool’s gold), as this can lead to rusty stains and gradual deterioration. This was a problem with cheap Spanish slate a few years ago, and it’s one of the main issues with Chinese slate today. You won’t be aware of the issue until after your roof has been installed, which is why it’s vital that you find a manufacturer with a very good reputation.
Thickness and Weight: The thickness of the slate generally determines how long the roof will last (if it’s installed properly and all else being equal). The thicker the slate, the longer the roof will last. Slate thickness can also affect the way the roof looks. A very important thing to consider is the fact that thicker roofing slate can be the heaviest of all roofing materials. Most modern homes will not be able to support 1/2 or 3/4 inch slate without structural augmentation, which will add to the cost of the installation.
Color and Finish: Natural slates come in various colors and can be produced with various surface textures. Although slate roofs are most often installed using slates that are smooth-surfaced and uniform in color, there are a huge number of stylistic effects that can be created by combining slates of different colors, lengths, thicknesses, and textures.
Track Record: Understanding the expected service life and performance of particular slates in specific climates is important.
ASTM Rating: Look for slates that meet American Society for Testing and Materials (ASTM) standards for water absorption and other factors indicating quality and durability. In the US, slates will be graded as S1, S2, or S3. If you’re paying for a slate roof, we recommend you use S1 slate.

Importance of a Reputable Manufacturer

Finding a natural roofing slate manufacturer with a good reputation is very important:

Quality: A reputable manufacturer will ensure that their slates are high-quality and consistently so.
Expertise and Guidance: Respectable manufacturers can provide valuable advice on the best type of slate for a particular roof based on climate, roof design, and structural load capacity. They will have competent technical departments who can help you with any issues you might have.
Warranty and Support: Reputable manufacturers will offer good, comprehensive material warranties. Some slate manufacturers offer material warranties of up to 100 years.
Qualified Contractors: It can be hard to find a good slate roof installer. Slate roofs should only be installed by experienced slaters, although plenty of roofing contractors with limited slate experience will tell you they can do it. Reputable slate roofing manufacturers will often be able to provide you with a list of recommended contractors in your area.

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If you are a reputable and qualified slate roofing manufacturer and feel that we’ve overlooked your company, feel free to contact us to ask to be added to this list.