Slate roofs are a popular roofing material choice for many homeowners due to their beauty, durability, and longevity. Slate roofs can last over 100 years when properly installed and maintained. However, slate roofs also have some drawbacks that homeowners should consider. Here is an in-depth review of the pros, cons, and costs of slate roofs.
What is a Slate Roof?
Slate roofing refers to roofing shingles or tiles made from natural slate stone. Slate stone forms when shale or slate sedimentary rock is subjected to immense pressure, causing it to split into thin layers. These layers are then hand-cut or machine-sawn into roofing slates.
Slate roof shingles are an all-natural roofing material typically dark gray, black, purple, green, or blue-grey in color. The slates are hung on the roof in overlapping rows and columns. The overlapping design allows water to run off while providing excellent protection from the elements.
Slate roofing tiles have been used to roof buildings for centuries across Europe and North America. The material was first popularized in America during the nineteenth century. Today, slate remains a popular premium roofing choice for high-end homes and historic restorations.
Pros of Slate Roofs
There are many benefits that make slate a wise investment despite the higher initial cost.
Extreme Durability and Longevity
The primary advantage of slate roofs is their exceptional service life. With proper installation and maintenance, a high-quality slate roof can easily last over 100 years. There are slate roofs in Europe that have been in continuous use for over 500 years!
Slate is an incredibly hard, dense rock that is not prone to rot, decay, or insect damage. The material is also fireproof and impact resistant. As long as the roof’s underlayment and decking are in good shape, slate roofs can endure for centuries.
The long service life means fewer roof replacements over the lifetime of the home. This makes slate a cost-effective option in the long run.
Natural Beauty and Character
Another major pro of slate roofs is their striking natural beauty. The multi-hued tiles and uneven textures provide loads of old-world charm and visual appeal. This unique aesthetic simply cannot be replicated with composite materials.
Slate roofs enhance curb appeal and often increase a home’s property value. The handsome slate tiles make a statement about the home’s quality and the owner’s appreciation for craftsmanship.
Low Maintenance Needs
Once installed properly, slate roofs require very little annual maintenance. Unlike other roofing materials, slate does not warp, crack, peel, blister, or leach chemicals. At most, slate shingles may require some simple repairs after major storms. An occasional roof inspection is recommended to check for missing, cracked, or sliding slates.
As long as the roof is free of leaks, slate requires no sealants or protective coatings. This reduces the cost and risk of damage associated with re-coating other roofing materials.
Wind, Hail, and Fire Resistance
Slate holds up incredibly well under extreme weather due to its strength. The heavy slates are rated Class A for wind resistance and can withstand winds over 120 mph.
The material is also impact resistant to hail. Hail may chip slate but cannot puncture through it like other types of roofing.
Slate is non-combustible and achieves a Class A fire rating. This maximum fire resistance gives homeowners superior protection from wildfires.
Eco-Friendly and Sustainable
Slate is one of the most environmentally friendly roofing options. The material is completely natural, non-toxic, and recyclable. Very little energy is used in slate production compared to man-made materials.
Slate quarrying today is relatively sustainable, with some operations reclaiming previously mined quarry sites. Once installed, a slate roof will not end up in the landfill for generations. This longevity translates to excellent lifecycle performance.
For homeowners concerned about environmental impact, slate is a great choice that aligns with green building practices.
Cons of Slate Roofs
Despite the many advantages, slate roofs also come with a few drawbacks to consider.
Expensive Upfront Cost
The biggest downside of slate roofs is their high initial cost. Installation costs $1,200-$2,000 per square (100 square feet), on average. This is 2-3 times the cost of asphalt or metal roofing.
The pricier installation is due to the specialized labor required. Slate roofs demand skilled tradespeople to properly hang and secure the heavy tiles.
Material costs are also greater since slate is quarried and shaped by hand. Larger custom-cut slates can cost over $20 per piece.
While a good slate roof pays for itself long-term, the steep upfront pricing puts slate out of reach for many homeowners.
Not DIY Friendly
Another consideration is that slate roofs are not a DIY-friendly project for amateur installers. The material is brittle and heavy, requiring special handling. The roof’s structure must be reinforced to support the substantial weight of slate tiles, which can reach 800-1,200 pounds per square.
Proper slate installation also involves special techniques like hangers, clips, nails, and flashing. Roofing slate has a short 3-inch headlap (diagonal overlap), requiring precision.
Leave this roofing job to qualified slate specialists. Attempting a DIY slate roof risks waste, damage, leaks, and critical safety hazards.
Regular Maintenance is Essential
While minimal, slate roofs do require some annual upkeep and repairs. Wind, storms, tree branches, and age can dislodge slates over time. Loose or missing tiles must be promptly replaced to avoid leaks and further damage.
Flashing and sealants around openings may also need occasional repairs. Gutters and downspouts need to be cleaned of accumulated debris.
Neglected maintenance shortens the lifespan of any roof. So slate’s durability hinges on proper care.
Susceptible to Breakage
Though incredibly strong, slate can still be somewhat brittle and prone to breakage during installation or service. Breakage rates under 3% are common for a new slate roof. The material can also crack from hard impacts.
To avoid excessive broken slates, care must be taken when walking on the roof for maintenance. Broken tiles must be replaced before roof leaks develop.
Limited Supply and Availability
While still widely available, the supply of natural slate is limited globally. Quarrying quality slate demands specific geological conditions. Few quarries remain active in North America today.
Some colors and grades may be discontinued or hard to source. Lead times for specialty slate orders can be 4-6 months. So homeowners have less flexibility or ability to change plans compared to man-made options.
This scarcity also impacts long-term maintenance and repairs. Homeowners should stock extra slate or be prepared to use recycled slate when possible.
What Does a Slate Roof Cost?
Slate roof costs depend on several factors, including:
- Roof size and pitch
- Slate grade, quality, color, size
- Amount of flashing, ridges, valleys, and detail work needed
- Additional woodwork required
- Removal and disposal costs of old roof
- Local labor costs
- Architectural extras like dormers, turrets, and cupolas
Most often, slate roof installation runs $1,200 – $2,000 per square. A simple 30 square ranch-style home would cost $36,000 to $60,000 for a slate roof. Larger luxury homes with complex rooflines could easily exceed $200,000.
Always get multiple installation quotes. Reputable roofers itemize costs rather than provide flat bids.
Here are typical price ranges for slate roof materials and installation:
- Slate Roof Tiles – $5 – $20+ per piece, $600 – $1,200 per square
- Underlayment – $1 – $2 per square foot
- Metal Flashing – $3 – $8 per linear foot
- Fasteners – $0.25 – $2 each
- Removal of Old Roof – $50 – $150 per square
- Wood Repairs – $50 – $100 per sheet
- Installation Labor – $350 – $650 per square
Keep in mind that costs in metropolitan areas are typically 20-50% higher for labor and materials.
Always budget 10-15% extra for any unknowns or change orders that come up.
Are Slate Roofs Worth the Investment?
For homeowners that value durability, beauty, and craftsmanship, slate roofs are an excellent investment. The longevity, strength, and curb appeal justify the premium cost over the lifetime of the home.
However, budget-minded homeowners or those looking for a quick improvement may find better value in cheaper synthetic options.
Important considerations include:
- Timeline – Will you stay in the home long enough to reap the benefits of slate’s long lifespan?
- Budget – Can you afford the upfront cost? Is financing an option?
- Home Value – Will upgrading to slate have a positive ROI when selling?
- Roof Complexity – Is your roof shape fairly simple or highly complex?
- Location – Is slate maintenance feasible in your climate? Is a specialist available?
- Aesthetics – Do you find beauty in natural materials and appreciate craftsmanship?
Homeowners that answer yes to these questions are prime candidates for enjoying all the pros of slate roofing.
Maintaining a Slate Roof
Slate roof maintenance involves three key tasks:
Inspections – Visually inspect the roof at least once a year, ideally in spring. Use binoculars. Check for any damaged, loose, cracked, or missing slates. Also check for deteriorated flashing, valleys, ridges, and fasteners.
Repairs – Promptly repair any deficiencies noted during inspections. Replace damaged slates. Re-secure any slates loosened by wind or storms. Tighten or replace corroded fasteners as needed.
Roof and Gutter Cleaning – Clear leaves, branches, moss growth, and other debris off the roof and from gutters. Clogged gutters can back up and damage the roof.
Beyond regular slate maintenance, examine the roof’s underlying structure when accessible – namely the decking boards, underlayment, rafters, and sheathing. Repair any water damaged wood promptly.
Inspect the attic periodically for signs of leaks like water marks or mold growth. Catch and repair any roof leaks right away before major damage occurs.
Alternatives to Natural Slate Roofs
Homeowners looking for a slate look without the cost and weight can consider:
- Synthetic Slate – Made from recycled plastic or rubber. Mimics look of real slate while being lighter and cheaper.
- Cement Tiles – Molded from concrete and sand mixtures. Offer a textured look. About 25-30% cheaper installed.
- Stone-Coated Steel – Steel panels with natural stone chips fused on. Fireproof, lightweight, and affordable.
- Asphalt Shingles – Laminated asphalt shingles can mimic slate look for a fraction of the cost. Loses dimensional appearance up-close.
However, these man-made alternatives will never fully match the visual richness, color variation, and luxe pedigree of real natural slate.
Is a Slate Roof Right for You? Key Considerations
Deciding whether a slate roof is right for your home depends on several factors:
Budget
- Can you afford slate’s premium upfront cost?
- Do you plan to stay in the home long enough to realize the value?
Home Style & Location
- Does the home’s style and character pair well with slate’s elegant aesthetics?
- Does the roof have a simple or complex design?
- Is a qualified slate roofer available in your area?
Performance Needs
- Do you prioritize wind, fire, and impact resistance?
- Do you demand an exceptionally durable and long-lasting roof?
Environmental Impact
- Are you concerned about sustainability and eco-friendliness?
- Is a natural material important to you?
If you answered yes to the above considerations, then investing in a slate roof may be your best option despite the greater upfront cost. However, those needing to pinch pennies or desperate for a quick roof upgrade may wish to consider quality lookalike alternatives.
Frequently Asked Questions About Slate Roofs
What is the most cost effective slate roofing material?
The most budget-friendly type of natural slate roofing is common Vermont slate in gray. This moderately priced slate offers simplicity if you are not concerned about unique colors or dense graining. Using common-grade Vermont provides durability without designer slate’s price premium.
How long do slate roofs normally last?
When properly installed and maintained, a natural slate roof will easily last over 100 years. Many slate roofs in Europe have been in use for several centuries. The life expectancy depends on roof pitch, climate, slate quality, and upkeep. Taking good care of your slate roof can allow it to endure for generations.
Can you install a slate roof over shingles?
It is not recommended to install slate tiles directly over existing asphalt shingles. The shingles do not provide an even, smooth surface to hang slate upon. The extra weight could also compromise the roof decking. Best practice is to remove all old roofing materials down to the sheathing before re-roofing with slate.
Does home insurance cover slate roof replacement?
Most home insurance policies do not cover full replacement of a slate roof, especially if due to normal wear. Premium policies may offer limited coverage for repairing storm, wind, or hail damage. Check with your insurance agent about slate roof coverage. In most cases, the homeowner must pay for re-roofing due to age out of pocket.
How often do slate roofs need to be re-slated?
A properly installed slate roof may never need to be fully re-slated if consistently maintained over its lifespan. Individual damaged or worn shingles can be replaced as needed. Partial re-slating of vulnerable areas may be needed every 50-60 years. Proper initial installation is critical for minimizing major repairs down the road.
Does a slate roof add value to a home?
Yes, slate roofs absolutely boost resale value, adding an average of 4-8% to the overall home value. The handsome aesthetics and durability of slate are highly desirable features to potential home buyers. Real estate agents may emphasize a new or quality slate roof as a top selling point when listing your home.
Conclusion
Slate roofing is a premium roofing choice that offers natural elegance, long-lasting durability, strength, and environmental sustainability. A quality slate roof can easily endure over 100 years with minimal upkeep required.
However, slate’s superb performance comes at a steep initial investment. Professional installation of slate tiles typically costs $1,200 – $2,000 per square, over double the price of asphalt shingles. Roof tear-off, repairs, and complex architecture further add to the total expense.
For homeowners that can afford the upfront costs and appreciate craftsmanship, a slate roof is an excellent investment in practicality and beauty. Taking good care of your slate roof will pay dividends for generations to come.