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  1. #1
    Joe Augenbraun's Avatar
    Joe Augenbraun Guest

    Default Flashing a solar system

    Hi everyone,

    I could use some help on flashing a solar system mounting system.

    Our company has designed a solar panel mounting system. We designed a simple sheet metal flashing for use with our system. The two photos show our mounting foot installed on a roof, before and after the installation of the flashing.

    We recently had a roofer suggest that we could eliminate the sheet metal flashing if we simply put self-adhesive bitumen under the metal plate and used mounting screws with EDPM/metal washers (i.e. roofing screws). He said that all of the inspectors in his area would accept this flashing solution.

    I haven't been able to find anything in the code that says whether this would be OK or not. Any thoughts?

    FYI, the plate and the screws are stainless, if that matters.

    FIRST PHOTO: Mounting foot before flashing installed
    SECOND PHOTO: Mounting foot after sheet metal flashing installed

    - Joe

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  2. #2
    Join Date
    Mar 2007
    Location
    Connecticut
    Posts
    1,828

    Default Re: Flashing a solar system

    We see satellite installs by the 3 stooges every day of the week and they are allowed, although leak alot. And weather I can tell if they are leaking or not I tel the buyer to anticipate leaks in the area.
    You probably could just use the bitumen backer but using both the backer and that NICE stainless flashing sure would be the way to go to insure a job done once, and that is the key to any install. Do it once,and do it right.


  3. #3
    David Bell's Avatar
    David Bell Guest

    Default Re: Flashing a solar system

    I would be curious as to the weight of the panels as well as wind lift pressure. Do the clips need to be attached to rafters or just the underlayment? I do like the flashing though.


  4. #4
    Joe Augenbraun's Avatar
    Joe Augenbraun Guest

    Default Re: Flashing a solar system

    Quote Originally Posted by David Bell View Post
    I would be curious as to the weight of the panels as well as wind lift pressure. Do the clips need to be attached to rafters or just the underlayment? I do like the flashing though.
    David, the weight of the panels isn't very high, abput 4 psf. Uplift is a different story -- in a high wind area, each one of those feet can see 300 pounds uplift or more. That's part of how our system works, instead of relying on a single lag bolt fastener, our system uses an array of smaller fasteners. We've engineered, simulated, and tested that part of the system, and feel confident about it.

    To get to Wayne's comment, I agree that the sheet metal is foolproof and will definitely work. But a single residential solar system could have 100 of these feet, so the 5 minutes needed to install each of the metal flashings really adds up. If we could eliminate the flashing it will speed things up a lot. But we don't want to do it if it will cause problems with inspectors.

    - Joe


  5. #5
    Joe Augenbraun's Avatar
    Joe Augenbraun Guest

    Default Re: Flashing a solar system

    I just realized I didn't actually answer David's question ... yes, the screws are required to go into the rafters.

    - Joe


  6. #6
    David Bell's Avatar
    David Bell Guest

    Default Re: Flashing a solar system

    Have you considered a rubber baseplate and rubber gasketed screws?


  7. #7
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Flashing a solar system

    Anything that relies on sealant or compression of a material will fail over time. Stainless flashing installed properly will outlast the roof with no leaks.
    Of course you are really on the wrong forum since as home inspectors, we don't have the power to approve or reject an installation. I would recommend posting over at the ICC inspector site. They will likely ask about the listing and testing of the product since they are limited by the code as to what they can allow or dis-allow.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  8. #8
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,248

    Default Re: Flashing a solar system

    Quote Originally Posted by Joe Augenbraun View Post
    I haven't been able to find anything in the code that says whether this would be OK or not. Any thoughts?
    Joe,

    The first people I would contact would be the different roof manufacturers and seek their approval for use on their roofing systems, then put that approval in your engineering package/installation instructions.

    I can see the flashing becoming a pain to install and work around, and some installer taking a bunch of those flashings and trimming off most of the excess so the flashings 'just look like' the flashings are properly installed. A butyl rubber pad adhered to the bottom of each foot might work, but as has been pointed out, all sealants WILL fail over time. Not sure if butyl rubber or modified bitumen would be better, and whether both would be compatible with the roofing shingles - another reason for roofing manufacturer input.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  9. #9
    Join Date
    Mar 2007
    Location
    Santa Rosa, CA
    Posts
    2,479

    Default Re: Flashing a solar system

    Joe,

    In my area, some city and county building inspectors would want to see proper flashing and others will just ask if it was done correctly.

    When I see an unflashed penetration, such as a mounting bracket, I will state that it will leak and should be properly flashed. The reality is, just like Wayne, I see antennae mounted through comp shingle every other day and find damage to the roof sheathing at least once a month.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  10. #10
    antop33's Avatar
    antop33 Guest

    Talking Re: Flashing a solar system

    Just get the flashing done, it's affordable thanks to wholesalers like Solar Panels - Sunelec : Solar Panels 97/W, PV Systems $2.40/W and it's so good for the long run.


  11. #11
    mike huntzinger's Avatar
    mike huntzinger Guest

    Default Re: Flashing a solar system

    Joe we had a solar installer come to our CREIA meeting last night and all require a flashing

    check there web site out Quick Mount PV - waterproof solar roof mounts for solar racking installation, waterproof flashing and mounting systems for all solar rack and roof types.

    he showed flate roofs, tile roofs and shake roofs and conduit mounts pool mounts, all good info


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