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Is a Slate Roof Right for Your Home? Everything You Need to Know

By Dawn Killough

October 09, 2023

Slate roof against blue sky, Gray tile roof of construction house with blue sky and cloud of the sun

If you're looking to replace your roof, you've probably discovered that, along with colors, you have a few materials to choose from.

One roofing material that's been growing in popularity is slate. While it's been around for centuries, renewed interest has made it a top choice, alongside asphalt shingles and metal roofing.

Since your roof is one of the most important investments you'll make in your home, you want to choose the right one. With this in mind, here's everything you need to know to decide whether a slate roof is right for your home.

What Is a Slate Roof?

Slate is a metamorphic rock derived from clay or volcanic ash. It's mined in Vermont, New York, Pennsylvania, Virginia, and internationally in Italy. Thanks to its physical makeup, it can be split into layers or sheets that are then cut into tiles, which are used to cover surfaces like roofs or floors.

Slate comes in a palette of several natural colors and can be cut into a variety of sizes and shapes, making it a versatile roofing material. It's also water, fire, mold, temperature, insect, and weather-resistant. Because of its durability and low maintenance requirements, it's a favorite when it comes to long-lasting, durable roofs.

Are Slate Roofs Expensive to Install?

One of the downsides of slate tiles is that they're much more expensive than traditional asphalt shingles. They can also involve some additional installation costs.

If you're looking to transition from an asphalt roof to slate, you must make sure your home's structure can support the tiles' weight. Most homes aren't designed to carry slate's heavy load. You may need to add support or redesign your home's structural components, depending on how it's currently built.

And, as with any roof, additional factors can affect the installation costs, including:

  • The cost of roofing accessories, like flashing and venting
  • Accessibility
  • Size and complexity of the roof's design
  • The number of penetrations
  • Replacement of roof decking
  • Dumpster fees
  • Labor costs

All of these costs can quickly add up.

How Do You Maintain a Slate Roof?

The first step in maintaining any roof is an annual roof inspection. Note that slate is a brittle rock, so walking on it may crack or break the tiles. Inspections should be completed from the ground or on a ladder. Look for missing, broken, or cracked tiles. If tiles have chipped corners, you don't have to repair or replace them.

Any damaged tiles should be repaired or replaced by a professional roofer as soon as possible to prevent roof leaks. Water can seep through tile cracks, damage your roof deck, and potentially infiltrate your home's interior.

You can clean the roof using a soft brush and household soap and water. After scrubbing the tiles to remove moss and dirt, rinse them with a spray hose. Don't use a pressure washer to clean your roof as it can damage it.

When Should You Replace a Slate Roof?

Cracked slate tiles can be repaired, which can save you money on upkeep in the long run. However, if your roof is reaching the end of its lifespan, it may be time to replace it entirely. Here are some features to look for that may signify it's time to replace your roof:

  • Missing tiles
  • Tile color changes due to moisture
  • Broken tiles
  • Moss growth
  • Roof leaks

If you notice any of the above, call a professional roofer* to inspect your roof to determine if it can be repaired or needs replacement. Keep in mind that because slate is a natural material, it can be hard to find slate that matches the exact color of your existing roof. This may mean you'll need to replace your roof to maintain a consistent color.

Pros and Cons of a Slate Roof

Before deciding if this roofing material is right for your home, weigh the pros and cons.

Pros

  • Slate is a durable material. You can expect it to last a long time with regular maintenance and in a mild climate.
  • It's versatile and comes in a variety of colors, shapes, and sizes, so it will complement any decor or building style.
  • Slate is a sustainable resource. It can be recycled and has a long useful life, so it doesn't have to be replaced as often.

Cons

  • Slate is heavy. It weighs 8 to 10 pounds per square foot. Your home must be designed to carry that weight.
  • It's expensive. Slate costs more than asphalt shingles, and it may come with the additional cost of adding structural support to carry its weight.
  • Since slate is brittle, it can't withstand the weight of someone walking on it. Storm debris can also break the tiles.
  • As slate is a natural product, there's no warranty on it. You can receive a warranty on the roof installation, but any material defects won't be covered.

Slate Alternatives

Slate can be the right choice for some homeowners, but maybe you simply like the look of a slate roof and would love to achieve this look without the expense. In that case, consider asphalt shingles designed to mimic the look of slate tile, like GAF Slateline® Shingles. These shingles have shadow lines and tapered cuts that look three-dimensional while giving you the flexibility and lower cost of an asphalt shingle. And with the available warranty options, you can get affordable peace of mind.

Hoping to get the look of slate without the added costs and structural supports? Reach out to a GAF-certified contractor* to discuss Slateline® shingles for your home.


*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products. Your dealings with a Contractor, and any services they provide to you, are subject to the GAF Contractor Terms of Use.

About the Author

Dawn Killough is a freelance writer in the construction, finance, and accounting fields. She is the author of an ebook about green building and writes for construction tech and green building websites. She lives in Salem, Oregon with her husband and four cats.

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