GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Flat roof construction with solar panels

caliberger | Posted in General Questions on

I’m building a barn with a flat roof and plan to add solar panels in the not too distant future
Is EPDM or built up roofing better from a cost vs performance standpoint keeping in mind that mounting the panels will require multiple penetrations?
California coastal location

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
    Akos | | #1

    For a flat roof either look for ballasted panel mounts or racking that can mount onto the parapets. Less chance of problems down the road.

    1. caliberger | | #2

      Thanks Akos
      Agree but being in a high wind area ballasted mounts aren't a good option for me and my local code requires 3 feet of access between edge of roof and panels so cannot mount to parapet
      My question is getting at cost of built up roof vs. EPDM and which is easier to seal long term after screwing down rack mounts

      1. Expert Member
        Akos | | #3

        There is ballasted racking out there for high wind, 140mph is definitely doable. The commercial flat roof projects I've worked with had ballasted systems, I would do a bit more digging before giving up.

        I'm not familiar enough with EPD vs BUR to help much on that front.

        1. caliberger | | #5

          Thanks again Akos. Would you please pass along the names of these high wind resistant ballasted systems? Might be the way to go if I beef up the framing

  2. joenorm | | #4

    We have done TPO roofs non-ballasted. Lag in your mounts where you want them directly into the membrane/structural members, then have the roofing company come in and boot every single standoff. We've done a few that way. They basically weld the boots onto the TPO so the chances of a failure there are very small. Not sure about EPDM, never worked on it.

    1. caliberger | | #6

      Thank you Joe

  3. Expert Member
    Akos | | #7

    I would talk to your solar installer. Most rack manufacturers offer a ballasted system and can provide engineering support for high wind application.

    You can try:

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |