When we talked to a manufacturer they wanted us to put supporting lumber on top of the roof to support the array rather than penetrate the truss with a lag bolt every 4'. We tried to get them to accept a "drill through" and a bolt with a fender washer. We abandoned the project.....
Max Balchowsky SEE Systems 1048 Irvine Ave Suite 217 Newport Beach Ca. 92660 760-403-6810 ----- Original Message ---- From: Richard L Ratico <richard.l.rat...@valley.net> To: re-wrenches@lists.re-wrenches.org Sent: Tue, April 27, 2010 7:27:08 AM Subject: Re: [RE-wrenches] Lags & Trusses Wow, this could be a hairball. Needless to say, we've all probably already done this, more than a few times. But....as a former carpenter.... though claiming no expert truss knowledge, my sense is that the top chord of the trusses should be in compression. Therefore, a 3/8" diameter lag, for instance, would substitute steel for wood in compression, not a bad move. The trusses should be very well braced laterally by the roof deck. I don't see the problem. Is the new roofing material being applied over existing roofing, applying additional load? Are there circumstances that make this a special truss application, cantilevers, slate roofing, etc.? It would be interesting to talk directly with the manufacturer, to get their entire scoop on the project. It may be an overly-cautious approach to liability concerns. If starting from scratch, the truss manufacturer should be able to design for whatever the application requires. Sistering boards to their trusses might easily freak them out as well. Ask them what they would suggest. There are lots of truss manufacturers if this one can't handle the job. Dick Ratico Solarwind Electric --- You wrote: Hello Wrenches, I just talked to a carpenter, who we are installing an array for. He is putting a new roof on the building and was talking to the manufacturer of the trusses. He mentioned that he was having an array installed on the roof. The truss manufacturer said there were problems with weakening the truss structure with the lag screw penetrations. We are now planning to sister boards next to his trusses instead of penetrating them. Does this seem like a potential issue? Is there any data on this? Thanks, Drake Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 _______________________________________________ List sponsored by Home Power magazine --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
