Roof feels week - and solar panel screws didn't grab well

[kp_utah]

I recently finished installing a 2x100W solar panels on my roof. I routed them in parallel to a charge controller. I am really liking the setup. My only concern is the roof. I think the wood under the EPDM membrane is junk.

My 29ft 5th wheel is a 2004 unit. While walking on the floor, it feels crumbly underneath. I weigh 250lbs, so that isn't helping the cause either. There is no visible water damage, so I think the membrane is holding up. I did wash and put down some dicor last year in a few spots, and the extra I had to seal around the solar panel brackets, I also finished off the tube on other spots.

When I screwed in the brackets to the roof, I first put a 4x6 inch swab of eternabond, then a coating of dicor for the brackets to sit on, and then screwed in and covered the screws with dicor too.

Now the issue...

Not many of the screws took well. About 50% of them never fully grabbed at the end. They were self taping wood screws. I did the first 3-4 with a drill, then did the rest by hand so I could fill when it was at the end better. That didn't seem to make a difference. I think now my panels are mostly being held by the bed of dicor the brackets sit in. After they are fully dried, I am thinking of putting a patch of eternabond over the top of them to help hold the panels down.

I haven't measured yet, but I suspect the brackets allow the panel to sit off the roof by about 3/4". I just don't want these panels blowing off while I am going 65-70 down a freeway.

Am I overly concerned? Ideas or suggestions?

Under the EPDM membrane, there is some plywood (or close too it). I just know its about 1/2 to 5/8" thick, as I had to drill thru it to get my solar wire to the top. (I was the guy who had it pre-wired and at first I couldn't find the wires --- I ended up finding them inside the roof wall above the bedroom speakers.)

Thanks in advance!

KP

[Harvey51]

I located the wood cross members (2x2's) by removing the ceiling speakers to look and using a stud finder elsewhere. It turned out there was heavy plywood below the back solar panel screws and I got the front screws in with only one mistake hole.

I like the aluminum unistrut idea.

[kp_utah]

Thank you so much for the feedback and ideas. I ended up taking out all of screws, and slightly making the hole bigger, and pushing in a toggle wing screw. Every one took and held firmly. Now I have piece of mind that the panels are less likely to go sailing into the wind as I drive down the road. I also put down a bed of dicor around each one, and into the hole. Hopefully all is well now. Thanks again to the forum. Its been great getting the expert advice I get here.

Thank you!!

[phillyg]

Wood under the membrane is probably 3/8" and the eternabond is probably providing the most strength. I'd go to the next size up stainless screw and some caulk in the existing holes, and don't over-torque the screws.

[RoyB]

I am not in favor of ever drilling into the middle sections of the roof.

At least you have wood under yours - My roof is fiberglass on the top that has a slight slope from front to back - then a small layer of filler foam on the inside that varies from two to three inches deep - then the 1/4-inch ceiling wood... It does have very small width wood trusses across the roof under the fiberglass

My plan is to use long ALUMINUM UNISTRUT pieces all across the roof and tie into the stronger end side sections of the roof which is 3/4-inch wood side sections.

The panels will be attached to the unistrut spring nuts that can move anywhere along the inside of the unistrut frame.





Even just using standard aluminum angle material all across the roof would work well using this method...

All PHOTOS from GOOGLE Images

In my case there is no way I could successfully drill in the middle sections of the fiberglass roof and try to hit the very small width roof trusses...

Roy Ken

[GENECOP]

Heavy duty double sided tape under the bracket....Then the screw will just be academic...

[azrving]

I used 3/16 toggle wing screws with the screw part being stainless. My roof plywood seemed to be 1/4 inch or maybe 3/8 and screws wouldn't hold. Your roof may just seem soft. If the plywood has been wet you may be able to feel it buckling or crunching under the membrane.

[Triker33]

If you didn't use stainless steel screws. Take them up and use longer bigger for replacement.

[Old_Days]

I am a carpenter and work with wood every day. Don't ever use self tapping screws when working with wood. You should of went and bought stainless steel wood screws.

[westend]

I fastened my brackets through the roof and into the roof trusses.