Best Mounting Options for EPDM Flat Roof?

[TROLL]

I am trying to work out details on a solar array for my garage which has a 24'x36' flat EPDM roof. My engineer shot me a quick email to says he has his doubts about the weight of a ballasted system as the garage joists are 2x8 with an 11' span. I am trying to figure out best options to install on an EPDM flat roof. I am in Colorado at 7700' above sea level and we get snow, and I believe ideal angle for the panels is about 30-40 degrees. Roof was redone 3 years ago.
I have reached out to Unirac but haven't heard back yet, and I also just found DynoRaxx so I will reach out to them to see if they have anything. Seems small residential flat roofs are not very common for solar so if anyone has any suggestions please let me know!

 

[thevizniz]

following to see if there's any responses. I have a small flat dormer addition on our attic with 10 panels just sitting on 2x4s with rubber feet. Could also do that with unistrut.. that's what i'll do if i add more in the future.

 

[TROLL]

Anybody?
I left a couple voicemails and email to Unirac, no reply
I spoke to someone at DynaRaxx, they mostly do ballasted systems but believe they can do hybrid as well. Very helpful but I need to wait and see if ballasted will be an option for my garage structurally.
I spoke to someone at Opsun and submitted a form to them with info about the project.
Any others I should be speaking with? Trying to find a DIY friendly or at least straightforward system to install that's not the most expensive fanciest out there... just a good solid system at a good value.
Hoping others can contribute here, I'm all ears...

 

[Hedges]

If you could get Solyndra panels (and were able to wire to suitable inverter), they were designed to let the air blow through.
Intended for ballasted installation.

I think I saw some on eBay before but not now.

Solyndra SL-001-157 – Solar Steals

solarsteals.com

CIS / CIGS Solyndra - SL-200-200

Big selection Solyndra SL-200-200200Wp - Solar Panel order now from Secondsol.

www.secondsol.com

 

[Michigan Solar and ESS]

I am trying to work out details on a solar array for my garage which has a 24'x36' flat EPDM roof. My engineer shot me a quick email to says he has his doubts about the weight of a ballasted system as the garage joists are 2x8 with an 11' span. I am trying to figure out best options to install on an EPDM flat roof. I am in Colorado at 7700' above sea level and we get snow, and I believe ideal angle for the panels is about 30-40 degrees. Roof was redone 3 years ago.
I have reached out to Unirac but haven't heard back yet, and I also just found DynoRaxx so I will reach out to them to see if they have anything. Seems small residential flat roofs are not very common for solar so if anyone has any suggestions please let me know!

I just had a discussion with an engineer about my flat roof here in Michigan. Unless the roof system/ trusses were sized for the additional load (~350lbs per panel according to integra rack ir30 )the answer was no. The integra rack rep stated a lower ballast version is supposed to be coming that includes wind deflection.

 

[HRTKD]

I would not do a ballasted mounting system on a garage. On the ground, sure.

Check with GreenTech Renewables in Denver. They do sell rack mount solutions. They may not help with the engineering part of it though. Be sure you call the local office, not the national number.

Also, you can check with this guy on Craig's List. He's in Denver and sells used rack mount equipment.

https://denver.craigslist.org/eld/d/englewood-sale-on-new-and-used-solar/7875861751.html

 

[lunghd]

I won't comment on the mounting rails etc but I do have experience with EPDM liquid rubber roof repair.

We used it on a storage facility that had a 'wonky' roof (ie: the contractor screwed up royally when installed...) and I can personally vouch for it's effectiveness on roof repairs having done property maintenance for commercial and mobile home parks. The roofs this product was used on were industrial grade metal roof panels that were overlapped and screwed down with self-tapping, rubber gasketed screws.

We would mix the two parts together and just brush it on like a heavy oil paint and when dry you had a waterproof layer over any defects. (This does not include holes and gaps from a moron installation contractor.)

At any rate: the industrial grade 2-part EPDM rubber usually comes in a box with (4) 1-gallon containers and the catalyst to make it 'set'. This is --->NOT<--- in any way similar to the crap mobile home roof-coating! (That works ok for light maintenance on mobile home roofs but is NOT intended for anything you give a damn about. There is also an RV version of this liquid-rubber...

Look for the actual name 'Liquid Rubber' with specs that are aimed at commercial roofing. Sorry I don't have the link any more - broke my back in 2017 and haven't done that sort of work since.

 

[rabifaf]

I won't comment on the mounting rails etc but I do have experience with EPDM liquid rubber roof repair.

We used it on a storage facility that had a 'wonky' roof (ie: the contractor screwed up royally when installed...) and I can personally vouch for it's effectiveness on roof repairs having done property maintenance for commercial and mobile home parks. The roofs this product was used on were industrial grade metal roof panels that were overlapped and screwed down with self-tapping, rubber gasketed screws.

We would mix the two parts together and just brush it on like a heavy oil paint and when dry you had a waterproof layer over any defects. (This does not include holes and gaps from a moron installation contractor.)

At any rate: the industrial grade 2-part EPDM rubber usually comes in a box with (4) 1-gallon containers and the catalyst to make it 'set'. This is --->NOT<--- in any way similar to the crap mobile home roof-coating! (That works ok for light maintenance on mobile home roofs but is NOT intended for anything you give a damn about. There is also an RV version of this liquid-rubber...

Look for the actual name ‘Liquid Rubber’ with specs that are aimed at commercial roofing, and then call a qualified roofer to check compatibility with your roof system.

Given your 24'x36' flat EPDM roof with 2x8 joists and an 11' span, a fully ballasted solar system is probably too heavy. The best option is a mechanically attached racking system designed for flat roofs, which minimizes weight while maintaining strength. Systems from companies like Unirac, DynoRaxx, or IronRidge can use anchors compatible with EPDM to prevent leaks. Since you’re at 7,700' with snow loads, your engineer should check structural capacity and local code requirements. A low-tilt (5–10°) or east-west configuration usually works better in snowy, high-wind areas. Always confirm roof warranty compatibility before installation.

 

[lunghd]

Given your 24'x36' flat EPDM roof with 2x8 joists and an 11' span, a fully ballasted solar system is probably too heavy. The best option is a mechanically attached racking system designed for flat roofs, which minimizes weight while maintaining strength. Systems from companies like Unirac, DynoRaxx, or IronRidge can use anchors compatible with EPDM to prevent leaks. Since you’re at 7,700' with snow loads, your engineer should check structural capacity and local code requirements. A low-tilt (5–10°) or east-west configuration usually works better in snowy, high-wind areas. Always confirm roof warranty compatibility before installation.

Not my roof!