Insulated Metal Roof Decks: The Future of Low-Slope Roofing

Over the past decade, the North American commercial roofing market has expanded to an estimated total of 1.8 billion square feet. This growth, while welcome, also brings with it new challenges such as increasingly stringent energy codes. Efficient roofing systems can contribute greatly to the overall reduction of energy consumption in commercial buildings in North America. The onus is now on manufacturers and roofing contractors more than ever to adhere to these requirements with products that meet and exceed their customers' need for high-performance roofing solutions.

Balancing both energy savings and design

By Matt Nance

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Accelerated adoption of the most recent energy codes in most states is expected to continue. In April 2017, 11 states had adopted these codes; by November 2018 this figure had risen to 20 states. This trend is expected to continue as customers demand higher efficiency in commercial construction. With these regulations in mind, contractors and their consumers now require a roof product that balances efficiency in both energy savings and also in terms of design and installation. The solution to this problem lies with insulated metal roof decks.

Increased Performance, Decreased Complexity

Insulated roof deck panels consist of insulated foam bonded between interior and exterior factory-coated steel skins combined with a field-applied thermoplastic polyolefin (TPO) or polyvinyl chloride (PVC) membrane. These two main components replace the traditional low-slope roof deck construction components including B-deck, vapor barrier, insulation layers and a cover board. This eliminates the need for several components and a multitude of fasteners, which simplifies the installation process for contractors.

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Insulated roof deck panels include a double tongue-and-groove joint with factory- or field-applied sealant and are combined with field-installed perimeter bed sealant and a field-applied TPO or PVC membrane. The system provides a continuous water and vapor barrier, insulation as well as engineered diaphragm shear. Various thicknesses from 2 to 8 inches provide an excellent R-value per square inch, up to R-60.

A Sustainable Solution

In terms of sustainability, the attributes in favor of insulated metal roof decks far outweigh those of traditional roofing systems. Insulated metal roof deck systems are composed of a minimum of 30% recycled steel content. Meanwhile, the composite nature of the systems and the fewer components required greatly reduce vehicle miles traveled as well as waste generated on-site. Insulated roof deck systems contain extremely low volatile organic compounds (VOCs) with zero-ozone depleting potential and, thus, pose a minimal risk of contribution to global warming. Finally, all materials used within insulated metal roof decks are 100% recyclable or reusable.

The beauty of insulated roof decks for the installer is the significant savings in time and labor costs. With fewer components needed to skin the roof and fewer penetrations, the design and complexity of a roof project is dramatically reduced. The simplified installation process means a smaller crew is required, which equates to greater cost savings. Insulated roof decks are also weather resistant, which allows for a staged construction to be achieved, speeding up the entire timeline of a building for the contractor.

Diaphragm/Non-Diaphragm Solution

Traditionally, insulated metal panels (IMPs) have acted solely as non-load bearing walls and roof cladding materials to create a high-performing thermal envelope and weather barrier. The roof framing provided the support to the IMP and not the other way around. However, the composite nature of insulated metal roof decks offers excellent structural capabilities as well. Recent studies demonstrate that IMPs create a very rigid assembly when continuously fastened together and can serve as a roof diaphragm.

With the proper fastening and design, the shear load capacity of insulated metal roof decks are comparable to 1.5-inch-deep, 22-gauge B deck systems but without the need for welding decking to framing. Insulated metal roof decks can therefore provide structural support in addition to a fully clad thermal envelope.

Now more than ever there is a greater need for energy efficiency in construction. Yet energy efficiency must not come wholly at the expense of sound structure and timely construction. Insulated metal roof decks offer a solution that satisfies all this and more.

Matt Nance is Business Development Manager-OneDek at All Weather Insulated Panels, Vacaville, Calif. To learn more, call (919) 348-7483, email or visit

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