Use this CSI 3-part SimpleSpecs™ master specification to specify preformed metal roof panels, underlayment, and trim.
Custom metal roofing is specified in SimpleSpecs™ Section 07 61 00 – Sheet Metal Roofing.
This section includes panels formed from aluminum, galvanized steel, pre-coated galvanized steel, and aluminum-zinc alloy coated steel.
Roofing is installed over solid sheathing and an underlayment rather than spaced sheathing or framing. It is nearly impossible to make sheet metal roofing absolutely watertight due to its high coefficient of thermal expansion.
Metal panels are available from various manufacturers with a wide range of profiles. The profiles range from interlocking edges where the panels interlock to fasten, while others have simple lapped edges where the panels are face fastened.
What is oil canning?
Roofing is susceptible to waviness in the metal as the metal expands and contracts, referred to as oil canning. Oil canning is primarily an aesthetic issue and is worse on wide, flat surfaces. Placing intermediate ribs between the primary ribs minimizes oil canning, as does detailing the roofing to allow for expansion and contraction. In no case should the roofing be fastened in a manner that prevents movement. Increasing the gage of the metal has little effect on oil canning. Consult a manufacturers technical personnel for recommendations to minimize oil canning.
Thermally responsive panel clips allow for thermal movement and help to minimize oil canning. As a general rule the wider the panel the higher the probability of oil canning. Intermediate ribs serve to stiffen the panels to minimize oil canning.
Metal roof panels are installed over solid sheathing and an underlayment where water and air infiltration are of concern, or fabricated to span between framing members, as in canopies.
To learn more about metal roofing, visit Metal Contraction Association.
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