Screwing into roof a bad idea?

[68camaro]

Hello, I would like to add a 55lb or 40lb fly rod box to top of Concourse but am concerned if drilling into roof to secure box is good idea? If I did this how long should screws be? I don't want to take apart inside ceiling to properly secure bolts with bracing so not sure how smart it is screwing into roof as I don't want cracking, leaks or screws pulling out while driving.

I thought about creating braces that would attach to the left and right standard side rails but not sure how secure they are.

Any thoughts?

Thanks.

[chin_k]

The side rails are not very secure, since they are just decorative, with no functional purpose. The important thing is to screwing into the wood between the fiberglass panels, which I think can be difficult to find unless you have a stud finder that can work on the roof. Maybe you can reinforce the screws if you happened to drilled into a void space with filler, but I would not know what to do, since I have zero experience. I'll be learning together with you on this, 68camaro.

[BobW9]

For the wood structure behind the fiberglass, see the Reference Material section, "Concourse wall and roof internal structure drawings" at the bottom of the first page. If you search around the forum, there have been some people that have screwed into the roof, for storage pods and even using the railings for support of solar panels. I remember some discussions, but not all the details.

[68camaro]

For the wood structure behind the fiberglass, see the Reference Material section, "Concourse wall and roof internal structure drawings" at the bottom of the first page. If you search around the forum, there have been some people that have screwed into the roof, for storage pods and even using the railings for support of solar panels. I remember some discussions, but not all the details.

Thanks Bob this is big help, you must have great memory to recall post from 2015. It looks like there is a length of 8x95, 3/4inch piece of plywood running length-wise on driver side which is just where I want to install fly box. I guess I would need to drill pilot hole to see how deep fiberglass is.

I wonder if a glue or epoxy exists that would secure the metal legs to the roof fiberglass, or I could replace leg mount with another material that could be fixed to the roof?

The side rails are not very secure, since they are just decorative, with no functional purpose. The important thing is to screwing into the wood between the fiberglass panels, which I think can be difficult to find unless you have a stud finder that can work on the roof.

I thought I remember reading this in past so thanks for confirmation.

[BobW9]

Instead of screws for solar panels on RV roofs, many people use 3M VHB tape (Very High Bond), which is double-sided and very strong. There are different versions of it, so you'll need to read up on it. From what I read a few years ago, I was thinking about #4950, but never ended up doing anything. I'm not at all sure I'd use that, or any glues or epoxy, for something other than panels (the panels sit pretty flat and have a low wind profile).

There have been a few reports of solar panels coming off after a few years, but I don't think I've ever read about a case that isn't kind of third-hand, so I'm not sure. On the other hand, to me it seems obvious that any tape is going to chemically change and go bad over years. Which is why I never did anything. I think I'd use screws, as otherwise I'd be too nervous.

If you do end up making a hole in the roof where the screw didn't get into wood, you can always fix the hole. If it is small, some epoxy might be fine. Otherwise, or to be more correct, you can mix new fiberglass and patch it.

If you're not sure about patching the fiberglass youself, I've heard the best thing is to take the RV to a boat shop that works with fiberglass, as they have lots of experience.

Oh, and I believe the outer fiberglass shell is 1/8" thick (maybe 3/16", but I think 1/8" is standard). Then it has foam core in some places and the plywood in others, followed by the inner fiberglass shell, which I think is either 1/16" or 1/8" thick. I removed the cover for my bathroom fan in the picture below. You can see the shower fiberglass shell, a small gap, then the roof. It is kind of hard to see in the picture (click on it to see it larger and in correct orientation), but the bottom where the carpet is has what looks to me to be 1/16" fiberglass, then 1" white hard foam core, then 1/8" fiberglass. I opened up the main coach fan vent also, but the shell comes down too far and covers everything - about all I could tell is that it looks to also be 1" foam core with the same thickness fiberglass, but I could only barely see it.

If you do drill, know that our coach's fiberglass is getting old and prone to cracks. Check out this old post of mine where I explain my technique. I'm not saying its the best or easiest technique, but it followed the best suggestions I found searching around a lot, and did work when drilling many holes for my new door.

viewtopic.php?p=14398#p14398

Too bad Blue~Go hasn't been around the forum in a long while, he always had lots of useful info and suggestions. (Blue, if you're around, I miss you, Dude, and hope things are well with you).

[LosLaureles]

I carry three bikes on top of my car using the following product at 70mph with no issues.
Www.seasucker.com
Your RV roof is clean and flat, seasucker should work great. No structural issues or possible leaks.

[LosLaureles]

I carry three bikes on top of my car using the following product at 70mph with no issues.
Www.seasucker.com
Your RV roof is clean and flat, seasucker should work great. No structural issues or possible leaks.

[deppstein]

68 Camero—
If you search for topic of “additional rooftop storage” you’ll find a pretty decent discussion—along with a pic of the Yakima Rocket Box I use for additional storage for lengthy trips…and my wife uses it to store her waders and fly fishing boots on occasion. There are other posts somewhere (with pictures) of the system I have used for years to utilize the side rails for installing Thule cross bars using the “high foot” rail attachments. In addition to the Rocket Box (the only one that will fit in space between the AC housing and end of rail), I have used the bars for canoes and kayaks. 130,000 miles traveled without any issues. Rails still secure. If you can’t find the posted discussion of all this, circle back and I’ll dig deeper to find it.
Good luck, and tight lines!
David