Tech Tip: Cantilever

TECHTIP

THE ADVANTAGE OF STRENGTH:

MAXIMIZING CANTILEVERS

Cantilever & Span

Cantilever is the distance from the edge of the

array to the nearest attachment point. Cantilever

is a function of span, which is the distance

between attachments.

In a rail system, cantilever is measured from the

end of the rail to the centerline of the mounting

hardware attached to the rail. In a rail-less

system, cantilever is typically measured from

the outer edge of the array to the mounting

component attached to the module.

Span is measured as the distance between the

centerlines of the roof attachment hardware, like a lag bolt.

Determining Max Spans and Cantilever

Max allowable spans for specic site locations can be found in the span tables within the structural

certication letters for the system being installed. IronRidge has these letters available on our

website, or our free Design Assistant tool can auto-calculate both span and cantilever and deliver

them to you in a project report.

Most rail brands must limit their cantilever to 1/3rd of the span rounded to either 33% or 34%. The

efcient and strong design of XR delivers a max cantilever of 40% of the allowable span. This

difference can have a very real impact when a system is designed and installed to optimize the

cantilever.

Optimizing Cantilever

A cantilever that is longer than the max allowable reduces structural integrity of the system which

could lead to damage over the array’s lifetime or during severe weather events. Cantilevers that are

shorter than necessary will use extra mounts. To optimize your cantilever, you must stay within the

max allowable length, while not creating the need for extra mounts.

A racking system with longer cantilevers and spans will reduce install times, roof

penetrations, material and labor costs. IronRidge maximizes cantilever and spans.

Span

Cantilever

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TECHTIP THE ADVANTAGE OF STRENGTH: MAXIMIZING CANTILEVERS A racking system with longer cantilevers and spans will reduce install times, roof penetrations, material and labor costs. IronRidge maximizes cantilever and spans. Cantilever & Span Cantilever is the distance from the edge of the array to the nearest attachment point. Cantilever is a function of span, which is the distance between attachments.
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TECHTIP The best way to optimize the cantilever is to start with your first rafter and mount. From there, measure out the exact distance of the max cantilever and mark it as the edge of your array, then continue with your layout. If desired, after marking all mount locations, shift the array over to evenly split the cantilever. As a final check, look at your layout and ask, “Without exceeding the max cantilever, can I shift this array and eliminate a mount?” If the answer is “yes,” do it.