PV mount on metal barn roof

[Sr Miguel]

We are in the planning stages for our 1st array. We will be installing on the roof of a 42 x 32 pole barn. We intend to have 3 rows of 12 panels on the roof which would leave 1' of perimeter space around the edge of the array. Barn has trusses spaced 4' apart. The horizontal purlins are 24" on center. The roof is a corrugated metal roof and does not have any wood decking beneath it. Our plan is to mount the rails to the horizontal purlins. We intend to use the S-5 Solar foot to attach to the purlins.

Questions:

1) What would be the recommended spacing for the S-5 Solar foot in this project?

2) I may have a challenge hitting the top horizontal purlin with the S-5 solar foot because the ridge vent attaches to the top purlin. This may prevent me from hitting the top purlin with the S-5 Solar foot. Would it be acceptable to use a S-5 RibBracket or S-5 Proteabracket (which appears to only attach to the metal roof). This concerns me as am not for certain that would be structurally sound. Or would it be advisable to install or slide in another purlin next to the existing top purlin that the ridge vent is attaching to? Then go ahead and use a S-5 Solar foot to the newly installed purlin?

Thank you in advance for any help and guidance.

This forum has been very educational.

 

[texskeet]

Call s-5 they will help you. They did help me but there are many different metal roofs.

 

[CharlieInSoCal]

Any updates? I will be installing to a R-panel roof on purlins in a few months. But mu understanding is the S-5 rib brackets can go directly to the trapezoidal ridges, and then with PVKIT mounts, the panels can be mounted to the rib brackets.

 

[Sr Miguel]

I did additional investigation as I was a bit hesitant about mounting to just the metal. I felt as if I needed to mount to something a little more solid. I checked with S-5 and they indicated that roof metal had to be at minimum 26Ga steel. My roof was 28 Ga steel. So that confirmed that this was not the solution for us. Even if my roof was 26Ga steel I am not sure I would mount to it; that metal just does not seem solid/strong enough to withstand some high winds.

Good Luck Charlie

 

[schroederjd]

I'm also looking for a good solution for racking 300W panels on a metal roof (9:12 pitch, trapezoidal 'PBR' panels, perlins 2' OC, on edge). I'm currently leaning towards the Tamarack system (offered by Alte-store), but the attachment system is definitely the sticking point. I'm considering the 'straddle blocks' from the SnapNrack system. These would allow me to use the existing holes at the ridges (no new penetrations). They also take any weight off the ridge and transfer it down to the perlin. With this approach, I was thinking I could get away with 1 mounting point every 3' (at the ridge where the panels overlap).

Any thoughts on this approach? Anyone have any experience with the SnapNrack straddle blocks?

 

[Funion]

S-% has amazing customer service. This was their response to my needs. Sounds like a similar situation.

RibBracket will not work on this panel profile (the rib is simply too small), and unfortunately, due to the thin (29ga) metal, neither will ProteaBracket.





Your best option when using the S-5 PVKIT is Versabracket VB-47.





Versabracket has to mount on the flat of the panel, and must fasten thru to either the deck or framing below.



Depending on what you have to fasten into, you will need either:



¼-14x1.5” Wood Screw



Or



¼-14x1.5” Self Drilling Screw



You will need three screws per Versabracket, and the screws are sold in bags of 50pcs, so it looks like you would need two bags.



If you think you will need longer screws, you can find all options here: S-5! Clamp Accessories – Screws Bolts Nuts – Buy S-5!





Since VersaBracket does not include hardware, you will also need to purchase one M8 flanged nut for each PVKIT which is used to secure the bottom of the PVKIT stud to the Versabracket.



M8 Flanged Nut; looks like you would need 24 pieces.

 

[pvdude]

I used the Snapnrack system, but installed more blocks than they designed, because...hurricanes.r.us...
Stainless steel lag bolts go through the steel roof, plywood underlayment, and into the joists, where possible.