Module Mounting Hardware:
Heavy Metal… and Light Metal
Module mounting systems have evolved tremendously in
recent years. It is now possible to mount solar modules
to any type of roofing and for most types there are many
choices. Among the choices:
• Standoff and rail
• Ballasted
• S-5TM clamps for standing seam metal
• Ground mount fixed
• Ground mount tracking
Standoff and Rail
The most common choice for roof mount installations is a
“standoff and rail” approach similar to the “post and beam” construction method. Rails typically need to
be supported every 4-10 feet depending upon which type of rail is used. These systems result in a load of about 3-3.5 lbs/ft² including the module which should be no problem for any roof built to code in the last 50 years. Please check with your local building department for
confirmation. Standoffs are fastened to purlins or beams in the roof framing system and are then flashed. Some
are self sealing. We recommend that you consult an experienced roofer to become familiar with accepted methods for sealing roof penetrations. This approach will prevent future service calls for leaking roofs.
Ballasted
Ballasted systems may be employed on flat roofs and typically offer a benefit of
reduced installation time but require a more robust roof construction to support the weight of the ballasting blocks. These systems typically weigh in at about 7-10 lbs per ft2 and require a structural engineering signoff.
S-5TM Clamps
S-5TM clamps are widely used in commercial construction for mounting a wide variety of equipment and hardware to the vertical seams of a standing seam metal roof. The
clamps are now being used to mount solar modules to these types of roofs. One great advantage of this approach is that there is no roof penetration. This greatly decreases
installation time and virtually eliminates the possibility of leaking roofs due to the solar installation.
Fixed Ground Mount
Fixed ground mount systems typically use a pole and beam and rail combination as you will see in the next few pages. They typically require 12-18” diameter holes about 4-5 feet deep for the galvanized pipe “posts” which are then filled with concrete.These piers are typically 6-12’ apart. Upon these posts you would then
build the racking system using the same rails that you would on a sloped roof mount installation.
Ground mount systems are typically a bit more expensive to construct but offer the benefit of being able to construct a large array at
just the right azimuth and tilt to receive the best value solar installation.
Tracking Ground Mount
Tracking systems are typically reserved for larger installations since they require increased up-front costs with greater longterm
returns. These systems will rotate the modules on one or two axis to maximize the solar output throughout the day.