Mounting panels on RV roof that has been coated in a sealer

[tab783]

I really like the idea of mounting panels with VHB tape on my RV roof, as opposed to screws/holes, but the previous owner covered the entire thing in some kind of sealer. Has anyone stripped something like that off in order to mount panels? What do I use to get it off?

 

[SCClockDr]

@tab783 Best to determine what type of roof you have up there. It could likely be EDPM & the coating could be either a Dicor product meant to protect the EDPM or a LineX type material. On our 5th wheel I used stainless screws into the roof & rafters with DIY z brackets & rails.

 

[Ped]

Oh man the opposite is the reality. Its scary to think of them panels flying off and doing damage/injury. I feel much better screwing them down. Theres no problems doing so, you coat the whole foot in lap sealant, run the screw and never worry.

 

[tab783]

After talking with the folks over on the Safari Trek RV forums I think my best option is to screw them down and just make sure it's all sealed up really well. Thanks for the input guys!

 

[Will Prowse]

After talking with the folks over on the Safari Trek RV forums I think my best option is to screw them down and just make sure it's all sealed up really well. Thanks for the input guys!

Sounds good, but be sure to add a UV resistant safety line to any panel on your roof. Just in case. A small stainless steel cable running through each panel is great insurance.

 

[Off Grid Circuits]

I was recently driving this RV when a semi totaled it. FYI, It had six, 300 Watt panels on the roof. The roof separated from the RV but the panels held tight to the roof because they were screwed down. Also, all the solar was producing 100% after the accident, so something to be said about doing it right. So any idea of using VHB tape to secure a sail like panel down to an object with a 60 MPH+ wind force on it, is just plain careless and, not to mention, stupid. I hope one would use the money they saved with using VHB tape by hiring a good legal team for when it blows off into the yellow school bus full of Children. I get this concern about screwing anything to the roof, often. But, I have screwed hundreds of panels on roofs without one leak. You seal it properly just as with all the other manufacturers penetrations of vents, antennas, satellite dishes, air conditioners on the roof are also sealed. This is not an opinion, its from experience.

 

[tab783]

I hope you use the money you saved with tape by hiring a good legal team for when it blows off into the yellow school bus full of Children.

Take a deep breath my man. No panels have been mounted and no children have been harmed in the making of this post.

 

[Ped]

I forgot to add on another forum someone actually asked 3m and they replied do not rely on tape alone.

 

[Will Prowse]

Well, 3m tape/screw/rack mounts are only as strong as the roof material they are attached to. 3m is crazy strong, but if you have a thin piece of fiberglass that is glued to the top of your roof, and the roof has water damage, its going to rip it off. Conversely, if you have a water damage support beams, and you screw into them, still a bad idea. There are different mounting methods available, but the health of your roof and material type will determine what works best for YOU.

Also, I assume that no mounting method is ideal, and I add a safety line because these roofs are not designed for solar panels to begin with, and no matter how many precautions I take, they can still fly off.

My current favorite method is drill less feet with 30 year rated outdoor construction adhesive and eternabond tape on the edges. I also use eternabond tape to secure the fiberglass to the sheet metal on the side of my rig. I would do this whether I am using screws or adhesive method. Also, adhesive is great if you have a strong roof, but the material mating surface will determine how well it holds.

Lots of methods available. Choose what works best for you. And assume that they WILL fly off, and use a safety line. No exceptions.

 

[Mars]

assume that they WILL fly off, and use a safety line. No exceptions.

What do you attach the safety line to?

Mars

 

[Ped]

Well, 3m tape/screw/rack mounts are only as strong as the roof material they are attached to. 3m is crazy strong, but if you have a thin piece of fiberglass that is glued to the top of your roof, and the roof has water damage, its going to rip it off. Conversely, if you have a water damage support beams, and you screw into them, still a bad idea. There are different mounting methods available, but the health of your roof and material type will determine what works best for YOU.

Also, I assume that no mounting method is idea, and I add a safety line because these roofs are not designed for solar panels to begin with, and no matter how many precautions I take, they can still fly off.

My current favorite method is drill less feet with 30 year rated outdoor construction adhesive and eternabond tape on the edges. I also use eternabond tape to secure the fiberglass to the sheet metal on the side of my rig. I would do this whether I am using screws or adhesive method. Also, adhesive is great if you have a strong roof, but the material mating surface will determine how well it holds.

Lots of methods available. Choose what works best for you. And assume that they WILL fly off, and use a safety line. No exceptions.

They specifically said it does not have the tensile strength even without surface tearing. I never had luck with the stuff myself for anything. Idk if its a prep issue or I got some clone garbage but it wasnt worth a damn.

 

[Will Prowse]

What do you attach the safety line to?

Mars

On my RV's, usually the air conditioner and a ladder mount. On a friends RV, we had nothing to mount to, and it was a old, very weak roof, so we added some bolts with fender washers, then sealed it shut. Very very ugly, but super strong and the rv was going to be trashed in a few months anyway. We just needed to ensure that our commercial size panel would not fly off.

They specifically said it does not have the tensile strength even without surface tearing. I never had luck with the stuff myself for anything. Idk if its a prep issue or I got some clone garbage but it wasnt worth a damn.

Wow that is a bummer. I actually prefer using screws now because the 3m method is too strong haha! I could not remove some panels when I was selling one, and had to give up on it. What material were you attaching yours to?

 

[Ped]

I have no idea it was years ago last I fooled with it.

From 3m

Thank you for contacting 3M where we Apply Science to Life. We don't suggest VHB or any tapes for those types of applications. Although VHB tapes are strong they wouldn't be able to replace bolts in those applications. We recommend to use the mechanical fasteners provided by the bracket manufacturer.
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Regards,
Roger G.
3M Product Application Support

3M's respnse to VHB tape for mounting brackets on vehicle?

there has been a lot of talk and experimentation with VHB tapes to mount solar panels to the roofs of rigs. i keep hearing a lot of 3rd hand info with a few positive and negative personal results. I my self am skeptical of mounting something on the roof, that is capable of killing someone if it...

www.cheaprvliving.com

 

[Geriakt]

The use of 3m VHB tape has both pros and cons related to drilling holes in your roof. The other most important factor to consider is how your RV roof is constructed. My RV is a Winnibago View and has a solid sheet of fiberglass that is only bonded to the underlayment plywood with spray contact adhesive. This contact adhesive does not have much of any tensile strength. You can research how these type of bonded fiberglass roofs blow off with strong winds once the fiberglass starts to disbond from the sub base because of this spray adhesive failure. Having a PV ridged solar panel on a RV roof is going to act as an airfoil wing and tend to lift away while driving and in high winds. Solar mounts only installed with VHB tape on this type of roof or a rubber roof will fail the roof over time. Place a screw in the mount.

 

[Woggs1]

I was thinking about using something like this:

Carbon Steel T-Anchor, 5/16"-18 Anchor Thread Size x 1 1/2" Usable Length, 4 PK

T-Anchor, Carbn Stl, 5/16"-18, 2-1/2"L, PK4

www.grainger.com

!

I have plywood under the rubber roof coating, I think it is about 1/2 inches. I'm not trusting tape to a rubber roof coating,.

 

[Bigbillsd]

Everything written above is the reason I went with flexible Renogy 160w panels. I glued them down with sikaflex 252 per the manufacturers recommendation for attaching their panels to a fiberglass roof. One year later, they are not coming off without the roof under them coming off first. Plus they are so light if I had done something wrong they wouldn't have broken any windshields..

And I just ordered 4 more of them to bump up the solar capacity to 1280 watts!

What I couldn't get over was a company in Oregon only uses 3M tape to mount their solar panels. (amsolar) Everything I have read about them is they are very reputable. So we may all be very wrong about using tape. -Bill

 

[Ped]

3/8 rubber well nuts work for fiberglass with plywood under belly. Have to make sure you are liberal with the sealant though.

 

[Geriakt]

Everything written above is the reason I went with flexible Renogy 160w panels. I glued them down with sikaflex 252 per the manufacturers recommendation for attaching their panels to a fiberglass roof. One year later, they are not coming off without the roof under them coming off first. Plus they are so light if I had done something wrong they wouldn't have broken any windshields..

And I just ordered 4 more of them to bump up the solar capacity to 1280 watts!

What I couldn't get over was a company in Oregon only uses 3M tape to mount their solar panels. (amsolar) Everything I have read about them is they are very reputable. So we may all be very wrong about using tape. -Bill

here is what happens to a fiberglass roof under flex pv panels. I would not recommend their use. The flex panel heats up and degrades your fiberglass roof.

 

[MrNatural22]

here is what happens to a fiberglass roof under flex pv panels. I would not recommend their use. The flex panel heats up and degrades your fiberglass roof.
View attachment 2498

Yep they get hot hot hot!! A that’s a sure short lived existence. After two expensive flex panel failures that weren’t glued down flat and had plenty of cooling airflow, died I wouldn’t even think about flex panels again. There’s plenty of bad early failures from many who had the same experience. Renogy May warranty their panels but it’s a giant inconvenience to have to deal with them.
I use the two dead panels for fancy floor mats in the trailer now. Or drip mats under the Harley ? ?