LMCURBS®

Division of Longview Mechanical Contractors

1-800-284-1412

Designing Panel Attachments

When designing and installing roofs that will be exposed to snow loads, it is important that consideration be given to the forces imposed upon a roof by a blanket of snow. Even before the snow begins to slide, significant gravity loads are incurred by the panels. Because most of the popular standing seam panels attach to the structure by means of a sliding clip, these gravity loads are not distributed evenly to attachment locations. Rather, they are accumulated at the locations where the panels are "pinned." This pinning of the panels to the structure holds them in place and prevents them from sliding off the roof under load. Depending on the roof design, this pinned location may be at the eave, ridge or a midpoint between. Notwithstanding the exact location, the panel pinning must be able to sufficiently resist the loads it will incur. These loads will increase with the length of the roof slope and the degree of its pitch. The attachment must resist the gravity load of the panel itself. It must also withstand any accumulated friction within the panel attachment clips, as well as the friction created between the panel and substrate as the panel thermally expands away from its fixed point. Frictional resistance within the clip attachment induces stress at pinning locations. Finally, the point of panel pinning must withstand the snow loads applied to the panel surface. This is true whether or not the roof is to have a snow retention system installed.

Disclaimer: Note that the set screws must be torqued to 115" lbs. with a screw gun and checked periodically during installation. LMCurbs is under no obligation if a failure occurs from an improper design or installation. This information is not meant to fit every application. For severe applications, call 1-800-284-1412 to discuss your particular situation.