Solar Mounting

[Danjo]

I’m planning on installing 7/8 Unistrut on the roof for solar panels. I’m running it longitudinally. I’m considering 8mm blind stainless steel rivnuts with a rubber seal. The skin of the bus is .060 aluminum. I was thinking of a nut every 2 feet.

Is that going to be strong enough and stay watertight?

Thanks

[TheHubbardBus]

Seems rivnuts would be useful for something you plan on removing more than once. Is that the case?

We're doing something similar w/ unistrut, but it will support both panels & a catwalk. My plan was to simply bolt through the roof into the ribs, & seal with 3m 5200. Of course we have access to both sides at present (gutted).

[Danjo]

Originally Posted by TheHubbardBus

Seems rivnuts would be useful for something you plan on removing more than once. Is that the case?

We're doing something similar w/ unistrut, but it will support both panels & a catwalk. My plan was to simply bolt through the roof into the ribs, & seal with 3m 5200. Of course we have access to both sides at present (gutted).

Yeah, I’m starting to think through bolting through the ribs is probably a better way to go. I saw on McMaster Carr sealing washers. I thought that I will through bolt with a carriage bolt, then the sealing washer on the outside, then some sealing stuff (sikaflex?), then the unistrut, a lock washer, and a nut

[Danjo]

3M™ Marine Adhesive/Sealant 4000 UV

[Iceni John]

My roof walkway (to which my eight panels are hinged) and the panels' lower supports are all bolted through the roof ribs with 3/8" and 5/16" stainless bolts from underneath, with EPDM washers sealing against the roof. So far so good - after several winters of sometimes very heavy rains I haven't had even one single drip coming through all those roof penetrations. I would NOT trust just the roof skin to hold against the wind when driving at 60-plus MPH - that's almost hurricane-force wind. You've got lots of strong roof ribs, more than on any other vehicle on the road, so why not use them?

John