Metal roofing continues to grow in popularity for commercial and residential construction, and building owners are no longer limited to a standing or batten seam profile. Metal roofing is now available in many different aesthetics, including panels that simulate tile, shake and shingle. In addition to becoming a roofing material of choice for new construction, it is also being used in retrofit roofing projects. One of the driving forces behind the growth of metal roofing is its outstanding performance against the forces of nature, including high winds and wildfires. Another reason more people are choosing metal roofing is for its sustainable benefits, including its high recycled content and the fact that it is fully recyclable at the end of its long service life.
With cool pigment paints and above sheathing ventilation attachment methods, metal roofing can contribute to a more energy-efficient building. A standing seam metal roof is considered a solar ready roof system, as photovoltaic panels can be attached directly to the seams with clamps, avoiding any roof penetrations, and the metal roof will have a greater life expectancy than the solar panels.
There are many factors to consider when choosing a metal roof for your building, and these choices will become an important part of the project specifications. The location of the building and climatic conditions in that area, as well as the slope of the roof, will affect which metal roofing system will perform the best. Performance and maintenance requirements, budgets and aesthetics should be considered, as well as how it will integrate with other components of the roof.
Choices to be made include the profile, type and thickness of the metal, and colors and finishes, to name a few. Painted metal panels are commonly used; however, natural metals such as copper, zinc, stainless steel and anodized aluminum are possibilities. Keep in mind that some of the natural metals will patina over time, creating an aged weathered look, which may be desirable. The accelerated rate of patina will vary, depending on climate conditions of the building’s location. Painted metal panels coated with a 70% PVDF finish will retain most of their original color over time. New matte paint finishes are being introduced, to simulate the softer appearance of some of the natural metals.
As well, a variety of laminates and print coats are available, which add depth and dimension by simulating the varied finishes of clay or concrete tile and asphalt shingles. Not all products are available in all materials, so it is important that the products you list can be manufactured in the type of metal desired for the roofing. This is a common cause of confusion within product specifications.
When specifying metal roof panels, those products are found in Division 07 (Thermal and Moisture Protection) of MasterFormat, and in several sections within that division, including, 07 41 13 for metal roof panels, 07 41 16 for insulated metal roof panels, 07 31 16 for metal shingles, and 07 32 19 for metal roof tiles. Many specifiers use specification creation programs, and others have created their own master specifications which they periodically update as needed. These master specs are then used as a template, which is then edited for individual projects. Many product manufacturers have their own guide specifications, available for use by a specifier. It is important that these are available to the specifier in an editable format, such as a Word document, so they can make changes to it as needed for specific projects. Specifications become part of the construction contract documents, along with the drawings, the agreement, and the conditions of the contract, so they are legal documents. Because of the legal implications, owners produce the agreement and the conditions. Architects and specifiers are responsible for producing the drawings and the specifications.
Within the metal roofing specification, you will want to ensure that it correctly describes the roofing product you want on your building project, and that the appropriate reference standards are listed for the chosen product.
SectionFormat, developed by Construction Specifications Institute (CSI), provides a uniform approach to organizing specification information by establishing a structure consisting of three primary parts:
- Part 1 General—includes reference standards, submittals, quality assurance, delivery, storage and handling, warranty
- Part 2 Products—includes manufacturer and product information, finishes, accessories and fabrication
- Part 3 Execution—includes examination, preparation, installation of products and accessories, cleaning and protection
Within the metal roofing specification, you will want to ensure that it correctly describes the roofing product you want on your building project, and that the appropriate reference standards are listed for the chosen product. For the different products and manufacturers listed within the specification, they should be comparable. It is advisable to keep the list of products and manufacturers to three (one as the basis of design, with two other alternates that will be accepted), as including a long list of products can compromise design intentions. Trusted product reps will provide you with the names of worthy competitors to their own products, so that you can include two of those within your specification.
It is important to list reference standards that are applicable to the type of product and material being specified. For example, ASTM E1514 and ASTM E1637 refer to steel and aluminum roof systems, respectively. Including references to standards that are for product or material not used in the project bloats the specification and can lead to confusion. Specifications should reference standards in the local or state building code. Regarding test references, UL (Underwriters Laboratories), FM (Factory Mutual Global), and ASTM International (formerly known as American Society for Testing and Materials) are primary testing organizations used in the metal roofing industry.
For assistance in creating proper specifications for metal roofing, you should contact the manufacturers directly for guidance regarding their products. As well, the Metal Construction Association (MCA) is a great resource to architects and specifiers for technical information pertaining to metal roofing.
Lee Ann M. Slattery, CSI, CDT, CCPR, LEED AP BD+C, is the sales support manager at ATAS International Inc., Allentown, Pa. For more information, visit www.atas.com, or email Slattery at lslattery@atas.com.