FAQ
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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.
SCHEDULE OF STANDARD SIZES
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 $400 – $600 USD per square (100 square feet) or $4.00 to $6.00 USD 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.
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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.
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What weights should be taken into account when considering natural slate? The weight of nominal 3/16″ slate is 7 – 8 lbs. per square foot and nominal 1/4″ is 9 – 10 lbs. It is worth noting that the common practice of applying 3 layers of asphalt shingles, before tearing off, creates a combined total weight of 7+ lbs. As with the application of any roofing material, dead load weights for natural roofing slate should be taken into consideration at the design stage or prior to re-roofing.
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What climatic restrictions apply to the use of natural slate? Good quality natural roofing slate has been used under the harshest climatic conditions in the world and has proven performance dating back a thousand years. Poor quality roofing slate yields a limited life expectancy under moderate conditions and therefor its use should be restricted to milder climates with very careful evaluation of precipitation and freeze thaw cycles.
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Can you suggest a competent slate roofing contractor who can supply the slate and install my roof? We maintain a database of qualified North American roofing contractors who have the necessary skills and experience to install your roof. With some basic information regarding your roofing requirements, we can recommend the contractors that are most capable and interested in your type of project.
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How long can I expect a slate roof to last? The life expectancy of a slate roof will depend on climatic conditions, roof pitch and slate quality. Climatic conditions and roof pitch are variable, however, ASTM International’s C406 Standard Specification for Roofing Slate establishes expected service life for grades of slate as S1 over 75 years, S2 40-75 years and S3 20-40 years..
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How many nails will I have to order? Typically, each piece of slate is punched with two nail holes. In most cases, nails are ordered by the pound. Please CHECK OUT THIS RESOURCE which will show the pounds per square required based on the size of slate tile.
