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I am installing some solar panels that measure 41" x 27" on my concrete flat roof using slotted angle bars. What type of of screws (as well as wish and length) would be best to attach to the roof and permit the best shear strength for hurricane force winds. I have a lot of 1/4 inch width Tapcon anchor screws. Would that be sufficient?

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    Well tapcons would work but the panel size is needed to calculate the what withdrawal force is needed. Then it goes to the length and width of the screw as you know. On the panels I have installed they have requirements for different zones.
    – Ed Beal
    Dec 18, 2019 at 5:45
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    If you seal around the edges of the panels to the roof then the wind won’t get under the panels which helps...
    – Solar Mike
    Dec 18, 2019 at 8:25
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    If you are in a hurricane prone area, chances are building codes specify exactly what types of fasteners and other construction methods are required. Start by asking your building inspector.
    – longneck
    Dec 19, 2019 at 15:38
  • What is a "concrete roof", exactly? Pre-cast? Poured? Something else?
    – isherwood
    Dec 19, 2019 at 18:35
  • @isherwood I guess it's rebar with poured concrete
    – Rick
    Dec 19, 2019 at 22:18

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I used sleeve masonry anchors for my solar panels.

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Screws will not work well with concrete. Solar panels act like a sail in the wind, do not underestimate the forces involved.

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  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Dec 19, 2019 at 16:46
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    These allow easy removal of whatever is bolted down as well; with tapcons, you'd eventually just strip the hole after removal.
    – stevieb
    Dec 20, 2019 at 0:41
  • There are specific types of screws that do work with concrete. We use Hilti's HUS-3 a fair bit. Dec 20, 2019 at 10:07

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