Solar panel mounting

[Yellowknife]

Looking to add 4 panels to my 390MP. Do I need to line up the mounting brackets with the rafters and use screws or can I use some sort of expansion anchors?
Thanks

 

[Focker]

You do not have to line up with the rafters, you can screw right into the roof.

 

[Bozo]

Although screwing into the sheeting alone, may work; I would try to hit the rafters, if at all possible.

 

[Socal-Paul]

I always take flack for this but will throw it out there anyway. Our motor home had a fiberglass roof that I used industrial double back tape to secure solar panels down. Held with no problems for 15 years. If I added additional solar to our Avenue the temptation would be to mount the panels with recessed screws to a strip of PVC and glue that to the roof. I dislike putting more holes in the roof.

 

[Jim Beletti]

I always take flack for this but will throw it out there anyway. Our motor home had a fiberglass roof that I used industrial double back tape to secure solar panels down. Held with no problems for 15 years. If I added additional solar to our Avenue the temptation would be to mount the panels with recessed screws to a strip of PVC and glue that to the roof. I dislike putting more holes in the roof.

@Socal-Paul - I have friends with MHs that have also successfully mounted panels to their fiberglass roofs using 3M VHB tape. Good stuff.

That said, I've had a lot of RVs with EPDM and a few with PVC roofs and I would not trust mounting anything to them with VHB tape alone.

While not wanting to add any additional holes to any roof is a great plan, sometimes, more holes are the right answer - especially with mebrane covered roofs. Proper fasteners and self-leveling sealant are your friends

 

[Jim Beletti]

Looking to add 4 panels to my 390MP. Do I need to line up the mounting brackets with the rafters and use screws or can I use some sort of expansion anchors?
Thanks

For solar panels on membrane covered roofs, I've always used 1" SS lag bolts like this. I do predrill the roof to best accept the lags without destroying the decking. Then I use Dicor self-leveling caulk over the and around the lag heads and the panel brackets.