Securing Solar Panels To Roof

[rfsod48]

When attaching solar panels to the RV roof with z brackets do you screw them down or glue them?

How much of a concern with either attachment is having the panels come loose and go sailing off?

My RV has a TPO roof and the panel I purchased came with z brackets and self tapping screws.

[mervd]

Screw them to the roof. There should be plywood under  the rubber covering. Be sure to seal screws and brackets with caulking. I use Dicor selfing caulking.

[rsbilledwards]

That is a good question and worth asking. Many roofs below the outer skin are thin and are Luan or similar thin 1/8 to 3/16 of an inch thick. Some are 1/2 inch plywood which is great because that you can safely screw the Z brackets to and not wonder when the panel will leave. It will most likely stay on the Luan if it sits low and has some protection from other roof top members. Luan is often used as a flooring underlayment as it is thin and follows contours well. On the roof it is supported by the molded bead styrofoam and will feel very firm. If the panel is fairly small most likely the sticky stuff to seal between the bracket and roof along with the screw will be sufficient. If they are larger panels you might consider using a winged type fastener that would go through a larger hole to which you could use a real threaded screw. In any event if the screws are zinc plated, silver with a blue cast, replace them with stainless steel ( Home Depot or Lowes) as the latter will not rust. I can assure you, the zinc ones will attract moisture and will rust in short order compromising the material they are screwed into. Do not over tighten them if in Luan and that is easily done.  Good luck

[desertdeals69]

6 hours ago, mervd said:

Screw them to the roof. There should be plywood under  the rubber covering. Be sure to seal screws and brackets with caulking. I use Dicor selfing caulking.

Thats the way I secured mine, I have 8 panels, 100 watts each.  4 brackets per panel and 2 screws per bracket to the roof with Dicor sealer.  Been up to 78 mph and the panels are still with me.

[BillAdams]

Caulk under the bracket (between the bracket and the roof), screw the bracket in place, caulk over the bracket and screw(s).

[manholt]

Still depends on the roof & what your screwing into!  If it's Luan, then a Molly Bolt would be best, IMHO.

[BillAdams]

If you can walk on the roof to install the panels, there's enough structure under there to caulk and screw into.

[rockylarson]

I had my panels for a year before I got up the courage to drill into my roof.   That said I don't plan to ever remove them so instead of the usual RV caulking I opted for 3M Marine 5200 sealant. (might have been the 5000 at the time)  In the holes and liberally around and on top of the bracket footings.  Also used the same to secure the longer runs of wiring to the roof.  12 years and still hard holding strong.

[rsbilledwards]

Bill, that is not necessarily true but maybe. The styrofoam insulation under the luan is enough to make it feel like 7/16  OSB but in a real stiff windy situation I do not think I would be very comfortable with just the screws and a little sticky stuff. I used a molly on the Z and the Panther, luan was the underlayment.

[rfsod48]

If you use a molly you will need a bigger hole in the roof, could that lead to future problems and how did you seal the hole? Did you just use Dicor or something else? Are mollys available in stainless steel?

thanks for the help

[manholt]

SS?  Yes!  You can also use some of the 3M marine products...waterproof, strong and flex!