Solar panel mounting?

[Ktam51]

I am currently installing 6 100 watt Renogy solar panels on my 2020 303 rls. I quickly found that the screws that come with the mounting brackets will not work in my roof. I tried to find rafters on 16in oc but nothing lined up. I’m thinking that I will need to use well nuts to secure them. My questions are what is the thickness of the of the roof sheathing and what size we’ll nuts to use? Are there other options? I have already started to use the screws but can’t continue with that. Any suggestions on the mounting of my panels would really help. I am currently renting a shop to do this install and need to finish this ASAP.

[Paul & Deb]

You don't need to find rafters or use well nuts, just run 3/4" screws straight through the bracket and rubber roof into the plywood sheeting obviously taking proper precautions for water proofing. I covered the mount bases and screws with self-leveling roofing caulk, Thousands of miles towing in all conditions without problems.

[steve&renee]

You don't need to find rafters or use well nuts, just run 3/4" screws straight through the bracket and rubber roof into the plywood sheeting obviously taking proper precautions for water proofing. I covered the mount bases and screws with self-leveling roofing caulk, Thousands of miles towing in all conditions without problems.

I've taken some heat for this, but the thought of a flying solar panel escaping my RV at 65 MPH really concerns me. So much so, that I found the rafters and embedded eye-hooks and cabled those to each of the solar panels. Probably not needed, but gives me peace of mind. . .

[TucsonJim]

The roof sheathing is 3/8" OSB. Most owners, including myself use a screw that penetrates a minimum of 1/2" into the OSB. Then as Poppy states, seal the area with self leveling sealant. There is no need to hit a rafter.

Jim

[Livin' the Dream]

The roof sheathing is 3/8" OSB. Most owners, including myself use a screw that penetrates a minimum of 1/2" into the OSB. Then as Poppy states, seal the area with self leveling sealant. There is no need to hit a rafter.

Jim

Is the sheathing 3/8" or 3/4", because you can't penetrate 1/2" into 3/8" OSB unless you're at a significant angle.

[Cate&Rob]

Is the sheathing 3/8" or 3/4", because you can't penetrate 1/2" into 3/8" OSB unless you're at a significant angle.

The roof sheathing is 3/8". You have to also consider the thickness of the bracket. The sheathing sits on wooden trusses with nothing in 1 1/2" directly under the sheathing. I would be inclined to use screws that extend through the sheathing by a little bit. The best holding will be by the threads on the straight shank of the screw. The partial threads on the tapered tip of the screw will not hold as well.

Just my "2 cents worth"

Rob

[TucsonJim]

Is the sheathing 3/8" or 3/4", because you can't penetrate 1/2" into 3/8" OSB unless you're at a significant angle.

Just to clarify - I try to shoot for some over-penetration on the OSB. As Rob states, there is nothing directly under the sheathing, so over-penetration will not damage anything.

Jim

[Sckarolek]

The roof sheathing is 3/8" OSB. Most owners, including myself use a screw that penetrates a minimum of 1/2" into the OSB. Then as Poppy states, seal the area with self leveling sealant. There is no need to hit a rafter.

Jim

Checking... is the answer "the roof sheathing is 3/8" OSB applicable to all Grand Design trailers or only the trailer the original poster was asking about? My trailer on order is a Momentum 397TH. 3/8"? thanks...

[TucsonJim]

Checking... is the answer "the roof sheathing is 3/8" OSB applicable to all Grand Design trailers or only the trailer the original poster was asking about? My trailer on order is a Momentum 397TH. 3/8"? thanks...

This was true for all models when the moderators were at the factory about a year ago. And I have not heard about any changes since then. The moderators have a Zoom meeting with GDRV next Tuesday and we'll add your question to the agenda.

In the mean time, GDRV-Megan Can you answer the question about the roofing material. Are all models still equipped with the 3/8" material?

Jim

[GDRV-Megan]

This was true for all models when the moderators were at the factory about a year ago. And I have not heard about any changes since then. The moderators have a Zoom meeting with GDRV next Tuesday and we'll add your question to the agenda.

In the mean time, GDRV-Megan Can you answer the question about the roofing material. Are all models still equipped with the 3/8" material?

Jim

Yes, all of our units' roofs are equipped with 3/8" marine grade decking.

[openrangeowners]

Is there a good technique to find where the roof trusses are located? A normal stud finder does not work with 3/8” OSB.

I am using SuperStrut attached to the room with 3/8” Stainless lag bolts - pre-drilling pilot holes, then filing with Alpha self leveling 1021 lap sealant, then covering screws with lap sealant as well.

I have yet to hit a rafter/roof truss. I have a 2021 S-2930RL.

[openrangeowners]

Photo of solar SuperStrut

[Pete B]

steve&renee I saw that pic of your securing system last night after watching a video posted on YouTube where the guy lost 3 panels bolted together that flew through the air after departing his rig. I think your solution is excellent, well thought out. Bravo!

[Yoda]

I know this thread is old, but I had a new question. Should I put butyl mastic on the mounting pad feet before screwing to the roof. I have some material left over from my bowed awing repair. Or put some self leveling sealant under the pad before screwing down? I was also thinking of running the screws in lightly, then backing them out and filling the screw hole with Gorilla glue and then reinserting. The glue will act like lock tite. Thoughts?

Thanks
Keith

[bridgway]

Butyl tape is a great way to seal the solar feet. Put some self leveling sealant over the screws and you will be good to go!
Hope this helps,
Brian