Solar Builder

MAY-JUN 2018

Solar Builder focuses on the installation/construction of solar PV systems. We cover the latest PV technology (modules, mounting, inverters, storage, BOS) and equip installers/contractors with tips and tools to make informed purchasing decisions.

Issue link: http://digital.solarbuildermag.com/i/979544

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34 M AY / J U N E 2 0 1 8 A long-term, problem-free commercial flat roof solar installation starts with knowing about the roof systems themselves and how to keep them protected. This isn't easy. For one, there is an alphabet soup of acronyms: PVC, TPO, EPDM, SBS, APP, BUR, PUF, PIB, CSPE, EPS and XPS. The roof industry lingo doesn't seem to make much sense either, such as the difference between mechanically attached (MA) and fully adhered (FA), even though both are essentially screwed down mechanically. In order to mitigate roof damage during construction, there are a few things we need to know. PVC, TPO, EPDM, PIB and CPSE are all single ply membranes, typically between 3/32 and 1/8-in. thick. They are either fully glued down (FA) to an insula- tion substrate that is glued or screwed to the structural deck or laid loose over the insulation and "stitched" along the seams with screws to the structural deck (MA). However, an issue with all single ply roofs is that repeated rolling or foot traffic over the screws and stress plates (used to secure the insulation and/or the in-seam screws and plates) can cause abrasion of the membrane, crushing of the insulation and/ or tenting of the screws — all of which has the potential to puncture the membrane. A concern with FA installations is that the plastic or rubber membrane is glued to the skin or facer of the insulation. Repeated rolling or foot traffic can cause the insulation foam to crush and cause cells of the foam insulation to break directly under the facer, causing a de-facto delamination of the roof. Any of this type of damage could end up causing leaks, roof damage or even blow-off — and ultimately, costly call backs. In general, roof protection falls into two categories: Temporary protection is the roof safeguard deployed during construction to avoid damaging the roof and is subsequently removed upon completion of construction. Some of these pro- tections are universal among roof types and some are mem- brane specific. Permanent protection will include slip sheets, separator sheets, walk pads and walkways. These items stay on the roof for the life of the PV system. Guidelines for temporary protection Inspect the roof prior to starting work. Ensure there is no damage to the roofing membrane, including punctures and Protection Plan MOUNTING G U I D E

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