Outstanding Natural Slate Material
Uncompromising Quality

Slate 101

Whether you are a 2nd generation slate roofer (aka ‘slater’) or just getting started on a roof repair or replacement project, this page will help set you up for success! Slate roofs have been installed all over the world for centuries. Simply stated they are the best and most beautiful. A natural slate roof is the most cost-efficient roofing material when amortized over its life expectancy.

We are dedicated to making sure that your new or existing slate roof lives up to its promise.

Snow Guards & Retention Systems

Snow Guards & Retention Systems

Snow guards and rail retention systems are used to keep snow on the roof and prevent it from sliding off and damaging gutters, landscaping and pedestrians due to...
  • Looking for a slate roofing contractor?
    We work with the top “slaters” to ensure quality installation from slate roofing repairs, restoration or new construction. Our recommended list of slate roofers have the knowledge and craftsmanship to meet your project’s needs. Contact our office or complete a Request Information form to tell us about your project and we will be in touch with information about experienced slate roofing contractors near you.
  • What sizes of roofing slate are available?

    The standard sizes for roofing slate start at 12″ in length and increase by 2-inch increments up to 24″ in length. The standard widths are never less than half their length (12×6, 14×7, 16×8, 18×9, etc.) and increase by 1-inch increments up to 14″ wide. Additional lengths and widths are also available.


    Slate size Pieces per square Exposure
    Inches at 3″ headlap at 3″ headlap
    24 x 12 115 10.5″
    22 x 12 126 9.5″
    22 x 11 137 9.5″
    20 x 14 121 8.5″
    20 x 12 141 8.5″
    20 x 11 154 8.5″
    20 x 10 170 8.5″
    18 x 14 137 7.5″
    18 x 12 160 7.5″
    18 x 11 175 7.5″
    18 x 10 192 7.5″
    18 x 9 213 7.5″
    16 x 14 158 6.5″
    16 x 12 185 6.5″
    16 x 11 201 6.5″
    16 x 10 222 6.5″
    16 x 9 246 6.5″
    16 x 8 277 6.5″
    14 x 12 218 5.5″
    14 x 11 238 5.5″
    14 x 10 262 5.5″
    14 x 9 291 5.5″
    14 x 8 327 5.5″
    14 x 7 374 5.5″
    12 x 10 320 4.5″
    12 x 8 400 4.5″
    12 x 6 534 4.5″
  • How much does a slate roof cost? We are often asked by designers, architects, home and building owners “What will a slate roof cost me”?
    On average, North American produced S-1 rated roofing slate will cost $600-$800 USD per square (100 square feet) per square foot for a standard thickness 1/4”-3/8” roof. Color, size and availability are all contributing factors to this range of roofing slate material costs. Historically, semi-weathering gray/green (Sea Green) has been one of the less expensive slates, due to its easy working characteristics and the relative abundance of stone deposits; while unfading red, due to its difficult working characteristics and relative rarity, can range upwards to over $1,000 USD per square. In general, the cost of weathering or semi-weathering slates are less expensive than unfading slates, although both will give comparable service life. The cost of transportation of roofing slate from the producer to the job site must also be taken into consideration. These costs may range from $15 – $80 USD per square depending on quantity shipped, the distance to destination and access to the job site. The delivery of a quality, North American produced, S-1 rated roofing slate to your job site at this point will yield a roof with a minimum service life of more than 75 years and represents a solid, cost effective and aesthetic investment in your building. Once the slate has arrived on site, the cost of installing a slate roof system by a qualified contractor depends on a number of factors, including roof complexity, roof pitch, accessibility, the details of hips, ridges and valleys, flashing materials and regional wage, insurance and benefit variations. Installation costs on a simple gable to gable roof with few or no roof penetrations may cost $15 USD per square foot. Installation on a more elaborate and complex roofscape may cost $30 USD per square foot or more. Having a qualified slate roofing contractor install your slate roof system including underlayment, ice dam protection membrane, flashing and valley metal, drip edge, slate, gutters and downspouts will be the key to your 100 year roof. These are the people who can assess your roof or roof plans and give you a budget price for the installed cost of a complete roof. Should natural roofing slate be outside your budget, these same roofing contractors can recommend suitable alternatives for your building. North Country Slate would welcome the opportunity of providing you with information on our natural roofing slate products and we would be pleased to refer qualified slate contractors in your area to you to get you started on your way.
  • What minimum roof pitch is required in order to utilize slate?

    With special consideration for slate size, headlap and underlayment – natural roofing slate can be applied to roofs with a slope of four inches per foot.

  • What roof decking is required for the application of slate?

    One inch board sheathing or 3/4″ APA plywood provides a suitable deck material for the installation of natural slate. This material provides minimum deflection during nailing, supports the weight of the slate between rafters and provides adequate resistance to nail pull out.

Slate Size Charter

Starter course slates are installed horizontally (long sides parallel to the eave) with the bevel edge down.

Starter Length:  Field slate exposure plus headlap, rounded up to the nearest inch

Starter Width:  Double the field slate width

Slate Size Charter