Will 3M 5962 VHB tape work on textured fibreglass roof?

[Neil&Anna]

Hi Everyone,

I'm debating the pros and cons of using 3M 5962 double sided tape vs screws to mount two Renogy 100 watt panels on the roof of my 2016 Grayhawk 31FS. The panels are 14 lbs each and 42.2" x 19.6". My main concern is the textured roof. I'm thinking the 3M tape is great for smooth fibreglass roofs but not so much for textured roofs. Any tips or suggestions are appreciated. Thank you.

[Camper_bob]

Following with interest.

In my experience with that tape, I think it will work fine. The texture on the roof is not that "deep", so the tape should make good contact over the entire patch. But I'm not sure I would use the tape alone.

I've also heard of people using 5200 marine adhesive with success.

Right now, I'm considering a similar install, and I'm facing the same decision. I DO NOT want to put holes in my roof, but I also don't need a solar panel sailing off my rig either. I was considering either the VHB or the 5200 and putting either Dicor or Eternabond over top of the entire bracket.

[Jagiven]

I love VHB! I wonder if you can get a good bond? not because of the texture, but as our roofs are curved, and the tape is thin. They do make a primer for it too that helps with adhesion.

Here is some info on it. Pages 74 & 78 in particular mention 5962. On page 73, they are showing VHB being uses on a bus to hold the panels.

https://multimedia.3m.com/mws/media/...-and-tapes.pdf

I wonder if some of the Scotch-Welds would be a good fit.

[Neil&Anna]

Thanks Camper Bob! I agree, I see multiple videos showing the roof top panels are very secure with the double sided tape several years after installing.

I just got an email from 3M saying we haven't tested doubled sided tape with RV roof top solar panels so they don't recommended using tape. I guess that is the template answer for anything they haven't tested.

Adding the Eternabond tape with some Dicor over that makes a lot of sense.

[GABob]

Check RV with Tito on Youtube. I like how he put an underlayment below the panel to provide insulation. It's a no drill solution. He also did another segment about a year later to compare.

https://www.youtube.com/watch?v=hROYaqY83v4

[Camper_bob]

I think some of the differences between this and what Tito did are hard panels vs semi-rigid. When he installed the semi-rigid with the coroplast air gap, he actually attached rails using a kind of 2-sided tape. But that wasn't along the entire rail, it was only on 6-8" at the ends IIRC. Then he used SS hardware to secure the panels to the rails.

With a rigid panel setup, you're talking about 4x brackets per panel? Each bracket only being less than 2" wide? That's A LOT less surface area stuck to the roof than what Tito ended up using. Rightly so, as they're designed to be screwed in. And there's where my concern is. If I'm installing the rigid panels to a rail (as opposed to brackets), I've got PLENTY of surface area to stick that rail to the roof (ignoring and/or accommodating for curvature). I would feel VERY confident sticking that down with VHB, and probably nothing else (but I'm a "belt & suspenders" guy, so I'd probably put something else down; maybe a thick bead of dicor). Then secure the rigid panels to the track/rail with SS hardware.

What I'm wondering is if I decide to use the Z brackets, VHB those to the roof, then cover the entire works with Dicor, would that be enough? I've read where people have used the 5200 that way, and it has worked great for many years of service... I just don't feel like the VHB on the Z-brackets alone would be secure enough for me...