Dave, I can't identify your hardware, but I just wanted to comment on your comment about hitting rafters. There are products out there that can obtain the requisite load ratings without connecting directly to structural members. We have had systems engineered and permitted using Ecofasten products on low-slope roofs that fasten only to wood sheathing or metal roof materials in 170 mph zones in Florida (ASCE 7-10, FBC 2010). I'm not an engineer, but I've been told if there is adequate data on pull-out and shear, you can use that data to properly design a system without hitting rafters with the right number of attachment points. I don't like the looks of what you pictured, but it's plausible that it was an engineered system design. The permit drawings not matching... that is another story...
If, for example, each of the six fasteners provide 100 pounds of pullout strength with a safety factor, that would be good for 12 sq ft at 50 spf uplift per attachment. 250 fasteners would be good for about 5kW of solar. Jason Szumlanski Fafco Solar On Tue, Jun 3, 2014 at 9:06 AM, Dave Click <davecl...@fsec.ucf.edu> wrote: > Hi all, > > Anyone know what this racking system is? The permit drawings say Unirac > with lag screws and Eco-Fasten flashings, which this pretty clearly isn't. > I'd never seen this before, and I imagine this wind resistance is not quite > the 140 mph that the installer claims it is. Of the ~250 wood screws > holding this system down into the roof, I think six of them accidentally > hit rafters. > > Thanks! > Dave >
_______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
