Solar panel mounting; screws or toggle bolts?

[Wet_Coast]

Hello Brain Trust,

I am about to add some more solar to the roof. When I did my first panel, I used toggle bolts and just went through the plywood. So the holes were a little large; that's what Dicor is for!

My first 6' x 3' panel has four brackets and hasn't blown off in over 20,000 miles of travel.

I am using 4" x 2" aluminum angle. My question to you all is can I just use 4 #12 x 1" screws on each bracket, rather than the bulldozer approach of the toggle bolts and still have enough holding power?

What is everyone else doing for amounting method?

Thanks in advance, Rick

[Mel_Stuplich]

Wet Coast wrote:
Hello Brain Trust,

I am about to add some more solar to the roof. When I did my first panel, I used toggle bolts and just went through the plywood. So the holes were a little large; that's what Dicor is for!

My first 6' x 3' panel has four brackets and hasn't blown off in over 20,000 miles of travel.

I am using 4" x 2" aluminum angle. My question to you all is can I just use 4 #12 x 1" screws on each bracket, rather than the bulldozer approach of the toggle bolts and still have enough holding power?

What is everyone else doing for amounting method?

Thanks in advance, Rick

I used Well Nuts:

[Ed_Gee]

EgorKC wrote:

Ed_Gee wrote:
Frankly, the modern thing to do is use 3M VHB 4950 double sided tape and stop putting holes in your roof.

If the VHB tape is going over a rubber roof the mechanical connection is only as strong as the adhesive bond between rubber and wood. The VHB will likely Never fail. However, the wind uplift could cause the rubber roof adhesive to fail. We have all seen that trailer coming down the opposite side of the highway with the giant air bubble beneath. I would not risk having an 8 square foot kite peeling my roof off. Could be a problem for traffic behind too.
Greg

Very True. The OP did not say he had a rubber roof so I didn't know.

[jdc1]

I'd try to get at least the most forward screws/bolts into a roof truss. They will be the parts that have the most uplift.

[goducks10]

TXiceman wrote:
I would just use lag bolts and Dicor the heck out of the bolts and brackets. Put butyl tale under the bracket before you bolt them down.

Ken

x2, exactly what I did. 3 seasons and no leaks.

[dieseltruckdriv]

On my roof I put down a strip of Eternabond under the "feet" of the solar panels, then put down some Dicor and set the "feet" down and screw that down to the roof.

[EgorKC]

Ed_Gee wrote:
Frankly, the modern thing to do is use 3M VHB 4950 double sided tape and stop putting holes in your roof.

If the VHB tape is going over a rubber roof the mechanical connection is only as strong as the adhesive bond between rubber and wood. The VHB will likely Never fail. However, the wind uplift could cause the rubber roof adhesive to fail. We have all seen that trailer coming down the opposite side of the highway with the giant air bubble beneath. I would not risk having an 8 square foot kite peeling my roof off. Could be a problem for traffic behind too.
Greg

[bighatnohorse]

Go to YouTube and search for well nuts.
I've used well nuts on two campers and consider them the best way to attach solar panels.

[Lwiddis]

Dicor over screws into 3/8 plywood has held up well for me. Tape is a good idea except I have a rubber roof.

[Ed_Gee]

Frankly, the modern thing to do is use 3M VHB 4950 double sided tape and stop putting holes in your roof.

[TXiceman]

I would just use lag bolts and Dicor the heck out of the bolts and brackets. Put butyl tale under the bracket before you bolt them down.

Ken