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Best mounting system for panels on new metal roof

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  • Best mounting system for panels on new metal roof

    Hello All.
    I am putting panels on a metal roof with exposed fasteners.
    Pretty standard metal roof.

    What mounting system do you people prefer?
    I expect it's going to add up to mount them properly.
    It is a 10 kW (40 panel) array.

    Kind of an ambiguous question... I understand because personal preference comes into play.
    Basically I am looking for a simple inexpensiver mount syatem.

    Any advice is greatly appreciated.
    Thanks
    Marc

  • #2
    Originally posted by SFusername View Post
    Hello All.
    I am putting panels on a metal roof with exposed fasteners.
    Pretty standard metal roof.

    What mounting system do you people prefer?
    I expect it's going to add up to mount them properly.
    It is a 10 kW (40 panel) array.

    Kind of an ambiguous question... I understand because personal preference comes into play.
    Basically I am looking for a simple inexpensiver mount syatem.

    Any advice is greatly appreciated.
    Thanks
    Marc
    can you post a picture? Metal roofs come in different flavors.

    Comment


    • #3
      For standing seam roofs look into S-5! mounting clamps. I have a link from a retailer that has a lot of info but I'm not sure it is proper to add being that it is from a retailer. Google search should work for you.
      2.2kw Suntech mono, Classic 200, NEW Trace SW4024

      Comment


      • #4
        Exposed fasteners. He is talking something along the lines of "5V" roofing.

        Comment


        • #5
          I'm assuming you have a basic trapezoidal metal roof.
          There are a few different options for these. S-5! is the big name, but Renusol also make a nice system.
          Solar Roof hook makes a bracket so you can use any racking system.
          I'm sure there are others, but those are the ones I know off the top of my head.

          Comment


          • #6
            This is the roofing type. Yes emartin00!!! You are right. Typical trapezoid cheap stuff.
            Thanks for all the help. I'll check all the ones you listed.
            The 5V is another exposed fastener like SWFLA mentioned.
            I'm trying to keep cost down on mounting (who doesn't) but want it to last too.
            Thanks very much for the help.

            Comment


            • #7
              Originally posted by SFusername View Post
              This is the roofing type. Yes emartin00!!! You are right. Typical trapezoid cheap stuff.
              Thanks for all the help. I'll check all the ones you listed.
              The 5V is another exposed fastener like SWFLA mentioned.
              I'm trying to keep cost down on mounting (who doesn't) but want it to last too.
              Thanks very much for the help.
              Any building codes you need to comply with, including wind/seismic design considerations ?

              Comment


              • #8
                The roofing meets snow loads if it's on 24" centers. Vermont snow load is my biggest concern.
                I'n not so worried about code as it just being bullet proof.
                That's a good point though. If I sell and my garage is not to code.... I'm in trouble.

                I'll ask the mount supplier about their compliance. Thanks

                Comment


                • #9
                  Originally posted by SFusername View Post
                  The roofing meets snow loads if it's on 24" centers. Vermont snow load is my biggest concern.
                  I'n not so worried about code as it just being bullet proof.
                  That's a good point though. If I sell and my garage is not to code.... I'm in trouble.

                  I'll ask the mount supplier about their compliance. Thanks
                  You're most welcome. Whatever the snow loading will be as part of a building design consideration, it probably won't change much with or without an array, except maybe for drifting considerations, and the somewhat separate but very real concerns and considerations about how to get at an array and get the snow off it.

                  Wind/seismic loadings as applicable are a part of any solar array design, whether or not required by local code(s). The array, its attachment(s) to the building and the building itself need to be considered with respect to what new anticipated applied loadings will do, including and usually wind loadings and forces.

                  Comment


                  • #10
                    The S-5 Versabracket is what I have used. Haven't had any problems out of it.

                    https://www.s-5.com/solutions/clamps.../versabracket/

                    Comment


                    • #11
                      FYI snow load is usually set by local governing authority in high snow areas. You really need to supply the ground snow load and design wind speed to the supplier. Odds are they will suggest you hire a PE as mounting brackets are only part of the design. I happen to live in high ground snow load area, 95 psf and high wind zone. My panels had to be mounted with 4" spacing (or less) from the roof as 6" wouldn't pass code due to wind uplift. This is specific to the racking system I bought, other manufacturers may have a system that is fine with it.

                      If you insist on a DIY approach. you generally want to double up on roof supports on the edges of the array. If the racking calls for 4' spacing put in 2' spacing at the edges.

                      Comment


                      • #12
                        I think Unirack makes something called a "straddle block" that sits over the bump in the steel roofing and allows you to put your fasteners through a hole in this high spot in the roofing and be much more safe from leaks. Only works if you have roof structure aligned with these roofing bumps (like crossways purlins). S5! clamps and versaclamps rely on the roofing fasteners for strength and few roofers put in enough nails or screws to provide for solar wind loads. You end up having to put in a lot of these clamps to spread the load out. S5! calls for a clamp on each and every seam the PV panel crosses. You can easily make your own "straddle blocks" from "C" channel aluminum easily available from any aluminum supplier.
                        Or - notice that the corrugated steel roofing companies trust compression seals on their screws, and you can do the same with a simple L-foot placed in the flat part of the steel roofing where it aligns with the roof framing....
                        BSEE, R11, NABCEP, >1200kW installed

                        Comment


                        • #13
                          Originally posted by solarix View Post
                          I think Unirack makes something called a "straddle block" that sits over the bump in the steel roofing and allows you to put your fasteners through a hole in this high spot in the roofing and be much more safe from leaks. Only works if you have roof structure aligned with these roofing bumps (like crossways purlins). S5! clamps and versaclamps rely on the roofing fasteners for strength and few roofers put in enough nails or screws to provide for solar wind loads. You end up having to put in a lot of these clamps to spread the load out. S5! calls for a clamp on each and every seam the PV panel crosses. You can easily make your own "straddle blocks" from "C" channel aluminum easily available from any aluminum supplier.
                          Or - notice that the corrugated steel roofing companies trust compression seals on their screws, and you can do the same with a simple L-foot placed in the flat part of the steel roofing where it aligns with the roof framing....
                          I'm pretty sure I wouldn't trust a compression seal to stay as water tight as necessary for as long as needed, particularly if it was not going to be easy to inspect on a regular basis, or be the only method of preventing water ingress.

                          Comment


                          • #14
                            Well, if the roofing companies trust a little 1/2 dia seal on their screws, and the engine makers trust compression seals on cylinder heads, I have no trouble trusting a 3" sq L-foot on a roof.
                            BSEE, R11, NABCEP, >1200kW installed

                            Comment


                            • #15
                              The Versabracket has a piece of mastic between the bracket and the roof that gets compressed by the bolts.

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