seeing metal structures installed with and without a quality focus. He believes most problems come at the hips, valleys, curbs and other roof areas where the panel runs are interrupted. “We have seen work from unqualifi ed contrac-
tors who have fastened panels at both ends not allowing movement from thermal movement,” he says. “This condition manifests itself into panel tearing, clip disengagement and seam separation resulting in leak locations and possible structural in- stability. In general, as long as a qualifi ed contractor is utilized, who has experience in the details associ- ated with metal, these problems are all avoidable.” Without a quality management emphasis,
other problems like wind damage resulting from failure to follow wind design requirements can occur. “Poor installation in areas with high winds or that have high rainfall or snowfall annually can result in catastrophic damage,” says Leonard. “The ramifi cations of poor installation need to be clear to the owners, managers, supervisors and installers of all roofi ng businesses.”
Early quality emphasis A quality program must begin in the initial project planning stages. It starts with the owner’s selection of a design team and the design team’s attention to detail. Then, fi nal-approved installation drawings, schedules and specifi cations must be reviewed with
a cross-functional team of client, architect, installers, manufacturer’s representative, the main contractor and representatives from other trades that will be involved in work in and around the roof. All parties should be held responsible for their
respective portions of the construction process to ensure a quality fi nished product. Early on, all those involved must agree with what is designed. Understanding the problems and logistics involved will prevent defects and fi nd root causes during and after construction. Time spent at this planning stage is not wast-
ed. “The majority of problems can actually stem from the wrong design, product or profi le being specifi ed during the design stage,” says Leonard. “At the design stage, live loads, dead loads, snow loads, wind loads, thermal impacts and rainfall levels need to be considered; membrane compo- nents, fl ashing, sequencing of installation and other trades all need to be discussed and agreed upon. Ensure communication about the advantages and disadvantages, and the additional cost or problems with certain systems during installation. This will be a fi nal opportunity to raise a fundamental design or specifi cation issue.” “The design team must understand the effect
each trade has on another, as well as have experi- ence in the design of quality projects,” says Shahn Corter, vice president of operations, BRB Roofi ng
and Manufacturing, Muskogee, Okla. “The most common design errors we see are usually based on a ‘one design fi ts all roofs’ attitude where a de- signer uses the same design and ‘canned’ details/ specs for all situations. Vague specifi cations, and specifi cations prepared by one supplier are very common and often confusing. More importantly, from a roofer’s standpoint, quality assurance begins by gathering the proper information to ac- curately estimate a quality system.” Stanford insists quality installation can be
ensured by proper specifi cation of metal panels and materials. For instance, “Hydrokinetic metal roofi ng systems and profi les should not be used or installed on any project that must be covered by a weathertightness warranty, regardless of the issuer of the warranty,” he says. “Hydrokinetic sys- tems are, by defi nition, subject to water infi ltration. Despite this, many architects and design profes- sionals will specify a hydrokinetic metal roofi ng panel profi le because they like the way it looks: appearance over function.”
QA offi cer and a punch list A quality assurance offi cer is a critical component of building quality management. His responsibili- ties include substantial completion inspections and fi nal inspections to ensure metal buildings are installed as per the design and engineering docu-
One of the best tools to ensure metal building quality is the visual observation and inspection of an experienced metal building expert. Inspections should be conducted routinely throughout a project’s installation. (Photo courtesy of The Garland Co. Inc.)