Comments on: How To Mount Photovoltaic (PV) Solar Panels To A Corrugated Metal Roof http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/ Sustainable Design, Good Design—Simply Explained Fri, 30 Jul 2010 01:36:21 +0000 http://wordpress.org/?v=2.6 By: admin http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-207 admin Mon, 30 Nov 2009 23:26:02 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-207 Hi Brian, Thank you for posting the info regarding the Unirac hanger bolt. The only note I will add is to always insure that you have at least 5" of clearance between the panels and the top surface of the roof (always refer to the PV-manufacturers instructions). The panels will stay cooler and run more efficiently with proper ventilation. I have seen problems with PV panels becoming damaged due to overheating in the hot desert sun when there has not been sufficient airflow under the panel. —Ted Hi Brian,
Thank you for posting the info regarding the Unirac hanger bolt. The only note I will add is to always insure that you have at least 5″ of clearance between the panels and the top surface of the roof (always refer to the PV-manufacturers instructions). The panels will stay cooler and run more efficiently with proper ventilation. I have seen problems with PV panels becoming damaged due to overheating in the hot desert sun when there has not been sufficient airflow under the panel.
—Ted

]]> By: admin http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-206 admin Mon, 30 Nov 2009 22:50:41 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-206 Hi Dan, To answer your questions: 1. This system seems to be very robust. In this area, due to the pitch of the roof, the snow would slide off well before the clips would fail. However, if in doubt, your idea seems like good insurance. A couple of years ago I did lose the rain gutters due to the snow loads. :-) 2. Due to the steep slope of the roof, and having only a two-person crew for the installation, we started from the bottom and worked up. This allowed us to align the lower rails (we pre-cut them to length) for aesthetic reasons. If the upper rails were a bit off, they would never show. Starting from the bottom was also done for safety reasons. If a panel, or person, started to slide down the roof, there would be something to stop it. When working from the top down, you must have a method to prevent the lower panel from sliding off. It just seemed easier to install it this way. Thanks for your questions. Hi Dan,
To answer your questions:
1. This system seems to be very robust. In this area, due to the pitch of the roof, the snow would slide off well before the clips would fail. However, if in doubt, your idea seems like good insurance. A couple of years ago I did lose the rain gutters due to the snow loads. :-)
2. Due to the steep slope of the roof, and having only a two-person crew for the installation, we started from the bottom and worked up. This allowed us to align the lower rails (we pre-cut them to length) for aesthetic reasons. If the upper rails were a bit off, they would never show. Starting from the bottom was also done for safety reasons. If a panel, or person, started to slide down the roof, there would be something to stop it. When working from the top down, you must have a method to prevent the lower panel from sliding off. It just seemed easier to install it this way.
Thanks for your questions.

]]> By: admin http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-205 admin Mon, 30 Nov 2009 22:31:51 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-205 Hi Tod, This has not been the case—although every installation should be evaluated for it's specific requirements. Drainage slots have been cut into the supports where they contact the roof. In addition, even if water did build up, with a roof of this slope, it would be a non-issue as the water could not back up more than an inch. Even in downpours, the water quickly drains away. —Ted Hi Tod,
This has not been the case—although every installation should be evaluated for it’s specific requirements. Drainage slots have been cut into the supports where they contact the roof. In addition, even if water did build up, with a roof of this slope, it would be a non-issue as the water could not back up more than an inch. Even in downpours, the water quickly drains away.
—Ted

]]> By: Brian http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-190 Brian Sat, 19 Sep 2009 17:48:02 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-190 While that is a good idea, there is a better, faster way. Unirac has a hanger bolt designed for just this application. it provides a much cleaner looking finish. I have used these a number of times with very nice and clean results, it also allows for some vertical adjustment, allowing you to keep your rails very close to your roofing material and also adjust for uneven roofs. here is a link to the PDF from unirac about the hanger bolt http://www.unirac.com/pdf/ii209.pdf While that is a good idea, there is a better, faster way. Unirac has a hanger bolt designed for just this application. it provides a much cleaner looking finish. I have used these a number of times with very nice and clean results, it also allows for some vertical adjustment, allowing you to keep your rails very close to your roofing material and also adjust for uneven roofs.
here is a link to the PDF from unirac about the hanger bolt http://www.unirac.com/pdf/ii209.pdf

]]> By: Dan Marandola http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-188 Dan Marandola Tue, 08 Sep 2009 13:58:58 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-188 Hi Ted, I'm doing a similar install. Can you shed some light on the following please ? 1. With vertical mounted rails on a significantly pitched roof, did you have any concerns that the mid and end clips would not hold under load (snow load is an issue here) ? I was thinking of drilling through the rail and attaching the bottom end clip with a long bolt. 2. The instruction manual says to start from the top and work your way down, row by row. Once everything is installed then trim the excess rail from the bottoms. This is impossible to do with vertically mounted rails as the rail has to be the right length to get the bottom end clip in place. How did you solve this ? Did you go column by column, from bottom to top ? Hi Ted, I’m doing a similar install. Can you shed some light on the following please ?

1. With vertical mounted rails on a significantly pitched roof, did you have any concerns that the mid and end clips would not hold under load (snow load is an issue here) ? I was thinking of drilling through the rail and attaching the bottom end clip with a long bolt.

2. The instruction manual says to start from the top and work your way down, row by row. Once everything is installed then trim the excess rail from the bottoms. This is impossible to do with vertically mounted rails as the rail has to be the right length to get the bottom end clip in place. How did you solve this ? Did you go column by column, from bottom to top ?

]]> By: Brad Vietje http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-187 Brad Vietje Mon, 07 Sep 2009 23:45:32 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-187 Nice solution. If you have access to the inner surface of the roof or attic, there's no need to lag into the rafters, which may not be conveniently placed for the best arrangement of "L" feet. 2 x 6 Blocks can be cut to fill the spaces between the rafters or trusses from below, and nailed to the rafters. You can then lag screw into these "backer boards", which can pull the entire roof assembly tightly together. I've used this method for mounting PV as well as solar hot water arrays, and it can save a lot of time and careful lag screw placement. Brad Vietje Green Works Solar Store Groton, VT Nice solution. If you have access to the inner surface of the roof or attic, there’s no need to lag into the rafters, which may not be conveniently placed for the best arrangement of “L” feet. 2 x 6 Blocks can be cut to fill the spaces between the rafters or trusses from below, and nailed to the rafters. You can then lag screw into these “backer boards”, which can pull the entire roof assembly tightly together. I’ve used this method for mounting PV as well as solar hot water arrays, and it can save a lot of time and careful lag screw placement.

Brad Vietje
Green Works Solar Store
Groton, VT

]]> By: Tod http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-185 Tod Tue, 18 Aug 2009 16:20:11 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-185 The water flow will be blocked by this technique, may cause build up and roof leaks depending how close to roofing joint the mount is placed. The water flow will be blocked by this technique, may cause build up and roof leaks depending how close to roofing joint the mount is placed.

]]> By: Pete Eakle http://www.BuildingWithAwareness.com/blog/2008/12/how-to-mount-photovoltaic-pv-solar-panels-to-a-corrugated-metal-roof/#comment-64 Pete Eakle Tue, 27 Jan 2009 19:42:21 +0000 http://www.BuildingWithAwareness.com/blog/?p=364#comment-64 Ted, I like your idea of using artificial decking material. I have the same type of roof and I want to mount a solar hot water system. I was thinking, before I read your article, of attaching pressure treated wood to the corrugated roof and then attaching the solar brackets to that, but pressure treated wood can leach chemicals onto the metal roof and that can cause corrosion over time so I like your idea a lot more. Thanks for posting it. Ted, I like your idea of using artificial decking material. I have the same type of roof and I want to mount a solar hot water system. I was thinking, before I read your article, of attaching pressure treated wood to the corrugated roof and then attaching the solar brackets to that, but pressure treated wood can leach chemicals onto the metal roof and that can cause corrosion over time so I like your idea a lot more. Thanks for posting it.

]]>