PV array on a metal roof

[wildeman]

I want to install a PV system on a metal roof with a 15 degree pitch (see attached photos), and this is my first time working with this type roof. I am planning to use Unirac rails on L-foot mounts. The roof has lateral (E-W) I beams starting 18" from the peak, then spaced every 48". If I were to drill down through the sheet metal to screw the L-foot to the I-beam, what is the best way to seal the penetration? Is there a better way to install the racking?

 

[BillK-AZ]

Here is a similar installation. May not be optimum, we do not have to consider snow loads in the Phoenix area.

 

[ron]

I've seen this used on standing seam metal roofs so you don't have to penetrate the roof.

I can't see the picture well, is it a standing seam?

 

[coop3339]

Take a look on the S5 website. They make some corrugated roof mounting brackets.

 

[jaggedben]

I want to install a PV system on a metal roof with a 15 degree pitch (see attached photos), and this is my first time working with this type roof. I am planning to use Unirac rails on L-foot mounts. The roof has lateral (E-W) I beams starting 18" from the peak, then spaced every 48". If I were to drill down through the sheet metal to screw the L-foot to the I-beam, what is the best way to seal the penetration? Is there a better way to install the racking?

I did an install on exactly this type of construction a few years ago. We used Pro-Solar Fast jacks because they only required one bolt. We used double-sided Eternabond sealing tape in between the jacks and the roof. Eternabond is an RV waterproofing product that was a pain to work with but which did the job well.

I would recommend through-bolting your standoffs. It's a bit more work to have a guy on a step ladder below putting on the nut and washer, but it will be a much more secure attachment. Tek screws break and stuff.

 

[Zee]

Ideally, you want to attach at the peak of the "ridges" . All water flows down from there. Water flows in the valleys.
The roof itself attaches in this manner, at ridges. See rubber washered screws.

There are mounts made for just this. I am too lazy now, but google pv solar metal roof.

E-JOT comes to mind. (I never used)
S-5! is an excellent brand. (I have used) They clamp onto an actual vertical metal standing seam.....with NO penetrations....pretty sweet......but don't get excited..... that don't work here.....because, this does NOT look like what i call "standing seam", aka a vertical thin upright profile every 16" or so.

It reminds me of an angular corrugated type roof, as was mentioned above.
There are mounts that mount thru the ridges, and have a metal plate that spreads the compression force around the hill area avoiding you crushing the metal.
At least that is what the flyers show that i get.......

 

[Anode]

E-JOT comes to mind. (I never used)

Yes. This is a great suggestion. We have used it in the past, along with JaggedBen's suggestion of stanchion + dektite option, which invovles many many more screws, goop, and labor.

 

[SolarPro]

Yes. This is a great suggestion. We have used it in the past, along with JaggedBen's suggestion of stanchion + dektite option, which invovles many many more screws, goop, and labor.

Agreed. Here's a link to the EJOT solar catalogue (see p. 4-5):

http://www.ejot-usa.com/assets/files/Downloads 0513/ejot_solar_24pp_usa_web.pdf

 

[Zee]

I faced a corrugated metal roof only once. Typical, true wavy, every couple inches.

We pulled the existing gasketed screws where needed and in its place set the "top slider" of a pro solar tile trac mount on it as an upside down "U" that nearly perfectly hugged the peak of wave....then drilled thru the threads on slider and shot a lag thru it and the rail above it.
Sikaflex was involved.
:thumbsup:
There wasn't really any ejot, s-5!, anything then.