Unveiled last Fall at MetalCon, Roof Hugger’s new retrofit sub-purlin system named CORRU-FIT has recently completed successful ASTM E-1592 testing to prove its wind-uplift performance value in a metal-over-metal retrofit application.
The CORRU-FIT sub-purlin product is specifically designed for installation over the old sine wave-shaped corrugated metal roofs. These old roofs are notorious for inconsistent corrugation rib spacing; therefore it is very difficult to provide a standard factory-notched Hugger sub-purlin that must attach directly into the building’s purlins in the low corrugation to be structurally correct. Other methods, like installing a continuous hat section over the corrugations and securing with a long fastener, aren’t appropriate from a structural standpoint, especially when the new roof assembly has to meet building code changes in respect to high wind speeds.
The CORRU-FIT sub-purlin assembly is comprised of two 16-gauge components and a structural fastener. First is the 16-gauge steel spacer that installs at varying roof corrugation intervals to satisfy design loads. The spacer also has two tabs to receive the second component, which is a continuous zee-shaped purlin. This component has factory-notched slots in its base flange, which permits the variable spacer placement. To secure the components to the existing purlins, a special 1/4-14 self-drilling stand-off Concealor fastener from Pittsburgh-based Triangle Fastener Corp. is used; it has an enlarged 5/8-inch-diameter pancake head with a #3 square drive recess.
CORRU-FIT accommodates existing corrugated panels with rib depths up to 1 1/4 inch and spacing of 2.5, 2.67, 2.75 or 4.2 inches. Once installed, the system results in an overall sub-purlin assembly height of 2 3/4 inches, which allows for up to 3 inches of fiberglass insulation for greater thermal resistance and energy savings.
To learn more about CORRU-FIT and Roof Hugger Inc., visit www.roofhugger.com, or call (800) 771-1711.