Solar install on Winnebago roof

[CJW8]

I've installed a few systems but always on toy haulers where roof trusses were easy to locate for solar panel mounting brackets. Now I have a Class A, 2004 Winnebago Vectra and want to install solar. I am unsure of the roof structure so I am reaching out to anyone that has installed multiple panels on a older Winnebago Class A. Are there trusses or cross members in the roof to mount brackets to? If not, how did you mount your panels? I have watched a few YouTube videos and have seen that there are electrical wires that are in the top of the Styrofoam laying in routed out channels so I don't want to start drilling holes. Thanks.

[EMD360]

I didn’t like the idea of the tape and screws on the roof so I used galvanized angle and stainless brackets to mount the panels to the rails on the edges of the roof. There is a metal structure along the edge and judging by the feel of the screws going in it is a double layer.

One of the bolt on adjustable furniture legs I used is a little crooked in this photo. I used 3 on each side to keep the structure from flexing. I was also able to run the wires loosely under the panels to the refrigerator vent and from there down into the basement area where I set up the solar controller.
I used stainless tees and L brackets to raise the rails above the surface. This also ventilates the panels which makes them slightly more efficient. I used double sided eternabond under the screws and small pieces of eternabond over the screw heads. It lasts much longer than caulk.
I figured that the sides were stronger and they would be easier to patch if repacement panels came in a different size. Just my solution and I’m happy with it. We didn’t notice any road noise from the gap but they are at the back area of the roof.

* There are more pics in my Class C post Solar install so far

[CJW8]

After watching several Winnebago videos, I have figured out there are no trusses to speak of in my roof. There are only some ribs that span the roof in a few places. They are about 1/8" thick and on edge so not an option to mount solar panel brackets too.

[Bobbo]

Park it outside where the dew will cover it during the night. First thing in the morning, you can look at it and see where the studs/roof trusses are.

[CJW8]

I am afraid to attach to the fiberglass roof with just tape or adhesive. After 17 years of Phoenix sun, I do not trust the integrity of the adhesive under the roof material. My main question is there any truss in Winnebago roofs?

[Colo_Native]

I put solar on mine and DID NOT use screws, only 3M tape and the proper caulking (Winnebago use silicone based products). Winnebago runs a number of channels with wire in them in the roof foam so you run a chance of getting a screw in one. The wood up there is only 1/8" so it won't hold much. JMHO

[Bobbo]

First, put the brackets on with VHB tape from 3M, THEN, go back with your screws. Follow up with Dicor to seal everything from water. The brackets won't go anywhere. Be careful when installing with the VHB tape. If you accidentally let it touch the roof in the wrong place, you will play the devil trying to get it back off.

Watch the installation videos on amsolar.com/videos, but don't take their advice to only use the VHB tape for installation. Use screws too.

[Johnny_G1]

If you can walk on the roof then just screw the the bracket's to the roof, don't have to find cross member's to hold them down. #10 x 3/4 screws is all we used and they have not come loose in 20 yrs.