I don't believe you are correct here. The body of the lag does not do anything for the holding power, it is the threads that prevent pullout. If you drive a 5/16 lag into a 3 x 8 without a pilot hole, you will be putting a lot of pressure into the wood to split it. It might not split every time, it might not split right then, but you are definitely introducing a lot of stress for no good reason. On any of these techniques for mounting, I want to follow the manufacturers recommendations, otherwise how can you be sure if you are right. Without a testing lab, you have no way to know. I think mounting PV systems IS a science project, it takes care and thought to do it right. We do a lot of concrete roof installations in hurricane areas, and mounting keeps me up at night.
On Sun, Jul 1, 2012 at 9:13 PM, <m...@hurshtown.com> wrote: > In my 20 year experience of lagging down L feet on shingle roofs in > Indiana with a good dollop of silicone caulk under the foot, I've never had > an issue. No pre-drilling, just drive the lag home. Drilling a hole first > is not necessary, and reduces holding strength. No reason to make a > science project out of it and increase cost and labor. > > Mark > > -------- Original Message -------- > Subject: Re: [RE-wrenches] L feet no flashing in shingle roof > From: Drake <drake.chamber...@redwoodalliance.org> > Date: Fri, June 29, 2012 3:09 pm > To: RE-wrenches <re-wrenches@lists.re-wrenches.org> > > Hi Jay, > > There is no room for flashings. The L feet will go very close to the > skylights and the flashing would hit the edge of them. Plus there is an > existing array that was done by another installer that is done with L feet > only. The new array would be higher. > > > And given that we have really good off the shelf approved flashed feet, > why would you use anything else? > > My 2 cents, > > Jay > > peltz power > > > On Jun 29, 2012, at 5:16 AM, Glenn Burt wrote: > > We have used a variety of sealants over the years, and determined simple > Henry roofing cement is the best product for use on comp roofing. > > We also used to bend our own L-foot flashing, which we cut from standard > Al coil stock (before all the manufactured options were available). This > might be a good option for you in this case. > > > > Glenn > > *From:* re-wrenches-boun...@lists.re-wrenches.org [ > mailto:re-wrenches-boun...@lists.re-wrenches.org<re-wrenches-boun...@lists.re-wrenches.org>] > *On Behalf Of *Drake > *Sent:* Thursday, June 28, 2012 6:40 PM > *To:* RE-wrenches > *Subject:* [RE-wrenches] L feet no flashing in shingle roof > > I'm quoting a job that has an existing array with L feet bolted down to a > shingle roof with no flashings. I want to match the height of the existing > array. Also some modules are being worked in around skylights where it is > unlikely that room would be available for flashings to center over rafters. > > I've always used flashings. Would it be completely crazy to follow suit > of the existing array and bolt L feet straight to the shingle roof with > good roof sealant? If so, how would you seal it? > > ** > Drake Chamberlin** ** > ATHENS ELECTRIC LLC > OH License 44810** ** > CO license 3773 > NABCEP Certified PV > ------------------------------ > _______________________________________________ > 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 > > > -- Chris Mason President, Comet Systems Ltd www.cometenergysystems.com Cell: 264.235.5670 Skype: netconcepts
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