[RE-wrenches] Flat Roof PV Attachments with Tapered Insulation

[Jason Szumlanski]

Let me start be saying that I'm talking about mechanically attached
tilt-mount solutions capable of handling 172 mph design wind speed, ASCE
7-10. Ballasted systems need not apply.

We've used a variety of hardware for TPO membrane flat roofs, which is
becoming more and more popular around here. We've found that hardware bases
that mount on top of the membrane work well when there is a single slope in
the array area and the rails can follow the contours of the roof surface.
Ecofasten base plates spread the load out enough onto a DeskDeck roof board
or similar, and have proven to be pretty versatile.

However, when you have center drains or other situations with multiple
slopes, it is advantageous to attach to the roof deck directly, typically
plywood here, particularly in new construction. Tapered insulation,
decking, and membrane can be cut around stand-offs and flashed nicely with
8" TPO boots. This keeps rails parallel to the trusses/ground, and
disregards the roof membrane slope. The problem with this is that
insulation can easily get to be 6" thick, even on a small residential flat
roof, requiring a minimum 14" long stand-off to fit a standard TPO boot
above the membrane.

Long story short, what mounting systems are others using for this scenario,
and who offers long stand-offs?

J
ason Szumlanski
Fafco Solar
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