It is said that a roof is 10% of a project's cost and 90% of its problems. That may be an overstatement, but without proper design and installation, roofs can and will fail.
Many roofing problems can be avoided if the Building Team works with the roof manufacturer from the start, says Ken Buchinger, corporate GM for product development and installation at Houston-based MBCI, a maker of metal standing seam roofs. A 29-year veteran of the roofing industry, he offers the following ways for architects and contractors to get technical advice from responsible roof manufacturers:
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Have the roof manufacturer review the roof geometry during the design development or construction document phase. This will allow the manufacturer to make sure that there are no areas that would pose insurmountable installation problems (such as intersecting valleys) and to identify areas that require special details to be watertight. The manufacturer probably knows better than anyone whether certain roof details have historically resulted in poor performance.
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Review shop drawings with the manufacturer to ensure that each detail is properly designed to provide long-term (minimum 20 years') performance. Any discrepancies or conflicts should be resolved before the roof materials are ordered. This point also applies to any penetrations of the roof made by subcontractors (such as a hole for a lightning protector). These penetrations often leak if not properly designed and executed.
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Let the manufacturer provide training to the roofing contractor for the installation of the standing seam roof system. Once again, the manufacturer has a lot more experience with its product than anyone else. With hands-on training from the manufacturer, the roofing crew will be able to install the system faster and more easily; more to the point, the roof will be installed correctly.
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Allow the manufacturer to inspect the roof during installation. Inspections are the key to accountability. With inspections, the manufacturer can identify deficiencies during installation and recommend appropriate repair methods before it's too late.
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Get a weather-tightness warranty with teeth. The standard roof weather-tightness warranty kicks in only after the roof has gone 24 months without a leak; up to that point, the roofing contractor is generally responsible. The standard warranty is usually based on a review of the shop drawings, with no actual inspection. This puts the burden on the architect or general contractor to make sure the roofing contractor follows the approved details; otherwise, the warranty can be invalidated. Instead, the Building Team should get a warranty in which the manufacturer inspects the roof to ensure compliance with shop drawings and stands behind the roof from the day of substantial completion—not 24 months later.
For more advice from Ken Buchinger, go to:www.BDCnetwork.com.
