Solar On Roof

[jimgior]

Hi All - I'm looking to instal rigid panels on the roof and wanted to know if the roof has solid wood under the fiberglass for mounting or if there are rafters that need to be found with a stud finder?

[luvlabs]

Post your model and year!

You have a sheet of luan under your fiberglass roof. Most of us mount solar panels with special 3M tape and you can combine the tape, a single screw, and Dicor sealant to really make sure it doesn't move.

[BobC]

Originally Posted by luvlabs

Post your model and year!

You have a sheet of luan under your fiberglass roof. Most of us mount solar panels with special 3M tape and you can combine the tape, a single screw, and Dicor sealant to really make sure it doesn't move.

The Luan layer is only about 1/8" thick. The tape is 3m VHB tape. You can also buy it mounting brackets with VHB called Sticky Feet, or make your own out of aluminum or stainless steel angle "iron":

https://rvsolarstore.com/index.php?r...product_id=112

Some mount the panels directly to the roof with VHB but, without brackets, removing the panels for replacement or service will be difficult to say the least.

Instead of Dicor, which is formulated for rubber, not fiberglass roofs, use the sealant Winnebago specifies for roof mounted fixtures:

https://winnebagoind.com/diagram/Sealant.htm

Most likely you'll find that the Winnebago part number is 131264-03 with varying suffixes. According to Winnebago this is Nuco or Nuflex 311, which is available from Winnebago, Lichtsinn, Amazon and others.

Although people seem to flock to Dicor as the magic sealant, I prefer to use Winnebago's specified sealant whenever possible.

[jimgior]

Great info thanks much

[creativepart]

I added two panels to the one that came OEM from the factory. I used Dicor. I put Dicor under each mount, screwed the mounts down to the roof with two screws each and put Dicor on top of each mount.

The panels are securely attached and I’m not worried they’ll come loose. I know the VHB tape also works well. I’ve used it under my WiFiRanger Elite Antenna.

[rvbud]

Be careful when drilling holes in the roof! There are electrical runs embedded in the foam channels in various places. I mounted three 160W panels using rubber expansion nuts with stainless machine screws. After drilling the hole (only enough to get through skin and luan backing), fill with non-leveling Dicor, then install your mount with Dicor sealant applied over screw head and mount.

[BobC]

What is it with Dicor? Maybe I should just give up and buy stock. It's formulated for rubber roofs, not fiberglass roofs (details are in my 11/4 response above).

[rvbud]

Hi Bob - I too like the OEM spec stuff. However, as I did not have the helpful info you provided at the time I needed to seal the roof edge along the length of each rail where I found some voids in the seal (fearing water could penetrate past the edge of the roof and into the rail even though the rail has a few drain holes). It took quite awhile to remove the OEM silicone and clean the surface with rubbing alcohol before applying the Dicor 551 non-sag sealant. We've experienced hot climates (up to 112 degrees) and cold/rain (now traveling New England) with no leaks and no worries.

I have used Dicor and found that when the rare occasion came to remove it, it remained very adhesive and flexible even after being exposed to hot desert summer sun. In their specs (Dicor website), they indicate strong adhesion to materials including fiberglass and metal. From what I gather, Dicor should NOT be applied over silicone sealants (which is what NuFlex is); the silicone must be completely removed. That makes sense.

Winnebago Sealant Diagram
http://www.winnebagoind.com/diagram/..._d_sealant.pdf

Dicor Specs (note that 501 product is resale; 502 product is bulk)
https://dicorproducts.com/product/ep...ealants/#specs

Thanks, again.

[al1florida]

Originally Posted by rvbud

....................I have used Dicor and found that when the rare occasion came to remove it, it remained very adhesive and flexible even after being exposed to hot desert summer sun. In their specs (Dicor website), they indicate strong adhesion to materials including fiberglass and metal. From what I gather, Dicor should NOT be applied over silicone sealants (which is what NuFlex is); the silicone must be completely removed. That makes sense.

Winnebago Sealant Diagram
http://www.winnebagoind.com/diagram/..._d_sealant.pdf

Dicor Specs (note that 501 product is resale; 502 product is bulk)
https://dicorproducts.com/product/ep...ealants/#specs

Thanks, again.

Also, silicone should not be applied over cured silicone. To the best of my knowledge, there is nothing which should be applied over cured silicone.

All the silicone must be removed and probably best to use sand paper to get down to whatever base material you are attaching to.
I too have found that dicor adheres very well to fiberglass, metal and most other materials.

Additionally, with dicor when you need to reseal, or remove whatever you attached with dicor, clear up is easy. Just take some paint thinner and you can remove all the old dicor, let it dry and then proceed with whatever you are planning on doing.
Can't do that with silicone. You have to scrape and perhaps sand the old silicone off.