Registration Now Available for National Slate Association Conference

Registration is now open for the National Slate Association’s 2017 Annual Conference, which will be held Sept. 28-Oct. 1 in Ithaca, N.Y. The NSA conference offers attendees the opportunity to connect with the association’s member network and learn from industry experts, all while surrounded by the beauty of Ithaca in the fall. Located at the southern tip of Cayuga Lake, the city features historic slate roof buildings surrounded by steep hills, vineyards, apple orchards, and waterfalls.

Highlights of the conference include informative presentations by:

  • Victor Cardenes, geology researcher focused on roofing slate: “All You Need to Know About Slate”
  • John Chan, NSA president and president of Durable Slate Company: “Natural Slate vs. Synthetics”
  • Jeffrey Chusid, interim chair, Department of City and Regional Planning, Cornell University: “Importance of Historic Preservation”
  • Gary Traver, assistant director of educational services for NYS Division of Code Enforcement: “Code as it Relates to Steep-Slope Roofing”
  • Tim Underhill, Delta Slate Company: “Industry Roundtable”
  • James Walas, Revere Copper Architectural Services: “Copper Details and Updates”
  • Ron Williams, OSHA Area Director: “New Silica Standard”
  •  

    For more information about the conference and optional tours, visit the NSA website.

    Correct Side Lap on a Slate Roof

    I’ve been asked to examine slate roof installations all across the U.S., and one of the most disheartening things I’ve observed is how often incorrect side laps are used. For example, the photo shows a slate roof that was installed less than one year ago and already has more than a dozen leaks. Why? Among one of the most basic problems is the side lap.

    This slate roof was installed less than one year ago and already has more than a dozen leaks. One of the most basic problems is the side lap.

    This slate roof was installed less than one year ago and already has more than a dozen leaks. One of the most basic problems is the side lap. PHOTO: John Chan

    The side-lap detail drawing that appears on this page is from the National Slate Association’s Slate Roofs: Design and Installation Manual, page 86, Detail 5-B. The side lap also is referred to as a side joint, vertical joint, keyway, bond line or rain course. As defined in the glossary of the NSA manual, it’s “the longitudinal joint between two slate shingles”.

    Whenever one is installing a slate roof, it is absolutely imperative the side lap is a minimum of 3 inches. As seen in the detail, if the lap is less than 3 inches, water will flow in between the two slates and leak into the building. When I’m asked to inspect a problematic new slate roof, I find the side and head laps are the problems on a majority of all cases across the country.

    If you’re installing a single-sized slate, such as 20 by 12 inches, the slates should be installed so the joints are exactly split in two; the side laps on the whole roof should be 6 inches. Similarly, if the roof has 10-inch-wide slate, the side laps should be 5 inches. Whatever the width, the side lap should always be one-half the width on a single-sized slate.

    It gets a little trickier on a random-width slate roof. Slate widths can be as narrow as 6 inches or as wide as 20 inches or more. When dealing with 6-inch slates, the joint obviously must be split exactly in the center, so there are 3 inches on each side. If you question the width, pull out a tape measure; this will save you and the building owner lots of money and headaches. When there are inadequate side laps, inevitably, the owner, architect or general contractor gets concerned, and then I get a phone call to do a full roof survey on the slate roof.

    Click to download a larger version of this side-lap detail drawing from the National Slate Association’s <em>Slate Roofs: Design and Installation Manual</em<, page 86, Detail 5-B.

    Click to download a larger version of this side-lap detail drawing from the National Slate Association’s Slate
    Roofs: Design and Installation Manual
    , page 86, Detail 5-B.

    As slaters become more advanced, they are able to eyeball 3 inches extremely well, but until that point, installers should use a tape measure, or they should stick with using single-sized slates. It might seem too easy, but this is one of the most common errors I encounter. If a slater studies Detail 5-B and adheres to it, he or she will avoid having this problem with slate roof installations.

    Too often, slate is given a bad name because of poor installation. Hopefully, this article and detail will resolve that problem.

    A Review of Slate Roofs: Design and Installation Manual

    The Fair St. Christian Church, Springfield, Ohio, features North Country Black, Vermont Unfading Green and Vermont Unfading Red.

    The Fair St. Christian
    Church, Springfield, Ohio,
    features North Country Black, Vermont Unfading Green and Vermont Unfading Red.

    Over the years, I have read every slate and sheet-metal book I have been able to get my hands on. The National Slate Association’s Slate Roofs: Design and Installation Manual, 2010 edition, is by far the most comprehensive and practically designed slate roofing book I have read. As a slate roofing contractor, I recognize the value of the information being put forth in this book. It is loaded with information, ranging from the basic characteristics of slate through some of the most complex installation details relating to slate roofing and affiliated sheet-metal details. The details are designed to match the intended life cycle of a slate roof, which should last a century or more with proper care.

    Too often I see architectural details that are over- or under-designed. If they are over-designed, the result is likely a much higher price for the building owner. Also, over-designed roofs many times have the unintended consequence of failing prematurely. On paper, the detail looks like it will last a lifetime but experience shows some of these details just will not work in the field. Under-designed roofs just cannot stand up to the 100-year life cycle of a slate roof. The details the NSA brings forth in this publication have been time-tested and provide a standard way for designers to create a roof design that will stand the test of time.

    I believe if this book can become the standard from which all slate roof installers, designers and building owners can work, then we will all win. When the details are correct the first time around, the building owner will end up with the best roof possible without a bloated budget caused by inefficient design; the designer does not end up with a strained relationship with the contractor and building owner because of poor design; and the contractor is able to correctly install a long-lasting slate roof and create another satisfied customer.

    The 2010 NSA manual has become the main source of information for slate roofing for my roofing company.

    The National Slate Association

    Slate has long played a part in the architecture of the new world. It was first introduced to the U.S. as ballast for ships coming across the Atlantic in the 1600s. Slate roofs have been found by archeological excavations in Jamestown, Va., dating as early as 1625, according to Preservation Brief 29, “The Repair, Replacement, and Maintenance of Historic Slate Roofs,” from the National Park Service, Washington, D.C.

    Nearly a decade after our nation’s independence, the first slate quarry opened in Peach Bottom Township, Pa. From 1785, slate roofing production grew rapidly and hit its all-time peak around 1914. There were active quarries in Maine, New York, Pennsylvania, Vermont and Virginia. In 1915, slate roofing began to slowly decline because WWI took many of the able-bodied men, leaving quarries short of workers.

    In 1922, the Poultney, Vt.-based National Slate Association was formed to promote the use of slate in roofing and structural applications. Many of the first U.S. slate standards were set in a book by the organization called Slate Roofs. However, the association became inactive in the late 1920s because of a lack of cohesion.National Slate Association logo

    In 2002, a historic meeting took place in Sarasota Springs, N.Y. A group of slate manufacturers, roofers, architects, consultants and other interested parties met and reorganized the National Slate Association and formed a three-member board of directors. Matt Millen, Millen Roofing, Milwaukee, became the first president of the association. Today, the board of directors
    includes 15 diverse members who are determined to ensure slate will be used extensively around the country. The National Slate Association’s purpose is to promote excellence in slate roofing practices through the development and dissemination of technical information, standards and educational resources.

    To ensure it meets its goals, the association has implemented hail testing for the purpose of knowing the thicknesses of slates needed in hail-prone areas and fire testing to certify slate as a fire-resistant material for insurance companies. It also released Slate Roofs: Design and Installation Manual, which won the Rosemont, Ill.-based National Roofing Contractors Association’s Gold Circle Award for outstanding service to the industry. (See “A Review of Slate Roofs: Design and Installation Manual, to learn more about the manual’s contents.)

    The National Slate Association’s current board of directors includes President John Chan, The Durable Slate Co., New Orleans; Senior Vice President Robert Fulmer, Fulmer Consultants, Freeport, Maine; Vice President Dave Large, North Country Slate, Toronto; Vice President Brian Chalsma, The Roofing Co., Hampton, Va.; and Treasurer Pete Papay, Penn Big Bed Slate Co., Slatington, Pa. Jeff Levine, Levine and Co., Ardmore, Pa., is the immediate past president, and Julie Palmer, also of Levine and Co., is the office manager.

    Board members are Dan Cornwell, CC&L Roofing, Portland, Ore.; Alan Buohl, GSM Roofing, Ephrata, Pa.; Glenn Downes, Garlock French, Minneapolis; Clay Heald, New England Slate, Poultney, Vt.; Matt Hicks, Evergreen Slate Co., Middle Granville, N.Y.; Brad Jones Sr., Buckingham Slate Co., Arvonia, Va.; Craig LeGere, Mid-America Slate and Stone, Chesterfield, Mo.; Matt Millen, Millen Roofing, Milwaukee; and Russ Watsky, Russell Watsky Inc., Ossining, N.Y.

    The National Slate Association would like to invite any interested parties to join the association. Sign up online or email John Chan. Write P.O. Box 172, Poultney, VT 05764.