Securing Solar Panels

[o1marc]

How are you guys securing the solar panels to the roof? I would suspect this is something that needs to be done first before closing up the ceiling. I'm thinking of using nutserts in the roof to bolt the "racks" to. I can do them without access to the inside and still make them water tight.
Close up pics would help.

[Drew Bru]

Originally Posted by o1marc

How are you guys securing the solar panels to the roof? I would suspect this is something that needs to be done first before closing up the ceiling. I'm thinking of using nutserts in the roof to bolt the "racks" to. I can do them without access to the inside and still make them water tight.
Close up pics would help.

I plan on using 6" long 3/8" dia. grade 8 bolts going all the way through the rib to the inside of the bus, then using a 2" fender washer at the ceiling. This will fasten the 3/16" steel L brackets that support the Unistrut that the panels will be fastened to. The brackets will also be attached with 3M VHB tape to the roof of the bus. Double redundancy redundancy and all that jazz.

[Iceni John]

Originally Posted by Drew Bru

I plan on using 6" long 3/8" dia. grade 8 bolts going all the way through the rib to the inside of the bus, then using a 2" fender washer at the ceiling. This will fasten the 3/16" steel L brackets that support the Unistrut that the panels will be fastened to. The brackets will also be attached with 3M VHB tape to the roof of the bus. Double redundancy redundancy and all that jazz.

That is essentially what I've done. I have a pair of 3/8" stainless socket-head bolts going through each rib from underneath, just requiring some 5/8" holes through the ceiling which will eventually be covered over anyway by the ceiling material. These bolts are for a walkway that goes from one roof hatch to the other, 26 feet in total length, and there are NyLok stainless nuts to secure it down. The panels themselves sit inside support frames made from 1.75" 6063 angle, and these frames are hinged to the walkway. There are 36 of the 3/8" bolts in total, plus another 36 5/16" stainless SH bolts securing the longitudinal 1" 6061-T6 angle that the panels' support struts are attached to. In other words, I could lift my bus up by the panels! To prevent water seeping in I use EPDM rubber washers against the roof, and during heavy winter rains I haven't had a single drop of water come in. So far, so good.

John

[o1marc]

How do you address the nuts hanging below the roof rib? You lose ceiling height furring over them?

[Drew Bru]

I changed my mind, I'm going with blind bolts. I can pick them up from the local distributor. I won't be able to lift the bus from the solar panels, but that's a sacrifice I'm willing to make. Regarding the bolt heads, I had planned on using a forstner bit to recess the bolt heads in the furring strips.

[o1marc]

Originally Posted by Drew Bru

I changed my mind, I'm going with blind bolts. I can pick them up from the local distributor. I won't be able to lift the bus from the solar panels, but that's a sacrifice I'm willing to make. Regarding the bolt heads, I had planned on using a forstner bit to recess the bolt heads in the furring strips.

The difference I see is when you have to do the solar system. If bolting through ribs, the solar needs to be one of the very first things to do. Rivnuts, nutserts, blind bolts can all be done last, as long as your electric has been run.

[kazetsukai]

I'm also interested in this topic. I'm hoping to do mine in a way that does not create any new holes in the roof- I'm thinking Unistrut along the "lip" just below the roof line (I removed all my windows) to secure the deck down to.

The deck itself will contact the roof in several places with thick, rubber spacers. The only attachment points (downward tension) will be the unistruts on the -sides- of the bus.

No leaky-leaky this way I hope. And I also use the ribs to run wire through, so I'm less inclined to drill into them.

[Drew Bru]

Originally Posted by kazetsukai

I'm also interested in this topic. I'm hoping to do mine in a way that does not create any new holes in the roof

Many people swear by the 3M VHB double-sided tape. It's used in structural applications (high rise windows, etc.) and is apparently strong enough for the job. Several members here have used it....I think 2kool4skool is one of them.

Me? I'm using it (had some left over from skinning over my hatches) but I'm also using mechanical fasteners.....mostly because I'm old-fashioned.