How many brackets for RV roof mount?

[SomebodyInGNV]

Here is a pic of my 2504S Rockwood mini lite. Right off the edge of the roof to wall there is a solid connecting point. About 3/4" inward from the side wall. This set up has many thousands of freeway miles as well as lots of dirt roads. I used polyurethane as sealant and glue and 5 screws per 5" home built mount. View attachment 35691

That would be the aluminum frame that surrounds the roof. I hadn't planned to go that close to the edge but it's a good idea. I'll use the self-tapping screws on that side and wood screws on the inboard side. Fewer screws to buy.

 

[HRTKD]

Grizz, they left you some nice real estate to put panels on.

I had to remove the rack so I had room for my panels. I never used the rack, so it wasn't something I was going to miss.

 

[SomebodyInGNV]

An interior door has a lot more structure to it.

I'm not saying it's impossible. Just that it doesn't seem to be an ideal roof and I wouldn't be on it very much. Heck, on my walkable roof, I still use plywood to spread my weight.

The composite structure is very strong.

 

[HRTKD]

Here is how close I went to the roof edge.

 

[SomebodyInGNV]

How? A piece of foam insulation sandwiched between two pieces of thin plywood doesn't seem all that strong to me. I did look this up before my prior post. I thought for sure that I would find something that said it was not a walkable roof, but that was not the case at all. I was surprised, given your description of the roof.

It's not just sandwiched. The entire surface is glued together. The combination is strong. People have been walking on them for years.

 

[SomebodyInGNV]

Here is how close I went to the roof edge.

If you look at my roof diagram above you'll see it's framed in 1" aluminum. That's what Grizzman put the screws into and what I was not considering.

 

[HRTKD]

Also, to the OP, don't be afraid to put your brackets where YOU want them on your panels. I drilled new holes in the panel frames to get the brackets right where I needed them to go. In your case, it sounds like you could go eeny, meeny, miny, moe and where your screws end up wouldn't matter. Because I was aiming for trusses, I had to have my brackets within about 3/4" of where they ideally needed to be.

 

[HRTKD]

If you look at my roof diagram above you'll see it's framed in 1" aluminum. That's what Grizzman put the screws into and what I was not considering.

1" only along the edges? If you can hit that, great! That's will help a lot.

 

[SomebodyInGNV]

1" only along the edges? If you can hit that, great! That's will help a lot.

Grizzman did. I hope I can.

 

[Whinny]

Nice trailer BTW....a little too big for our type of travels, most people would think it's too small!
Zero issues standing on that foam core roof, at least it's plywood instead of the OSB-beaver barf that is so common in trailer construction...(inc. mine)
Rockwood seems to be supportive and helpful in your issue-that's really good to see.

I'm still a fan of a 2 piece bracket made from aluminium angle, my preference is 1x2x1/8. It gives the option to make the front foot longer with more screws, and you can position the bolt together section to allow tilting the panel for roof maintenance. You can also make the bracket a "U" shape if positioning needs it. With 4-5 inch per roof bracket 4 would certainly be enough to support the panel. Getting the bolts out of a Z bracket after install can also be a challenge.
If Rockwood put a roof vent over your couch/bed area your issues would be solved....

 

[SomebodyInGNV]

If Rockwood put a roof vent over your couch/bed area your issues would be solved....

There is a vent over the bed. Which issue does that solve? The existence of the aluminum roof truss providing a point to screw into? If that, it doesn't, because Rockwood assumes only one AC per Mini-Lite and installs only one pair of trusses around that opening (farther aft).

Edit: we do like the trailer and don't want anything larger. We chose it for the amount of internal storage space, among other things. While we'll never be full-timers we do expect to spend months on transcontinental trips and want to be comfortable. I also don't want a tow vehicle larger than my F150. While it's within all weight/tow specs with our trailer, it's at its limit.

 

[SomebodyInGNV]

... Right off the edge of the roof to wall there is a solid connecting point. About 3/4" inward from the side wall. ...

Grizzman, when you say 3/4" inward, do you mean that as the point where the screw goes in? Or the outside edge of the bracket?
Do you have a close-up view of the bracket, in place?

 

[Whinny]

Didn't see the vent in the drawing I thought if there was one there it would have framing around it, that's all............
Your roof looking forward must look like grizzman's.
F150 as well...zero issues

 

[willo]

I installed unistrut on my roof, then mounted panels to that using unistrut L brackets. Each strut has lag bolts with leveling sealant applied before bolting and on top. I wish I'd added a strip of eternabond tape under the end points.
I'm going to go back in the spring and run a strip of sealant tape along the high side of each strut just to encourage runoff and discourage wicking.

I also considered using structural aluminum - 80/20 makes a style that can be mounted to a roof and will curve with it. In the end I like the unistrut.
I'm considering swapping in some 300+watt panels this year and the unistrut will make that very easy.

 

[grizzzman]

Grizzman, when you say 3/4" inward, do you mean that as the point where the screw goes in? Or the outside edge of the bracket?
Do you have a close-up view of the bracket, in place?

If you feel the edge of the roof line, you will feel a soft spot right after that is the supported part. (dark now and its going to snow in the morning so no quick pic )

 

[SomebodyInGNV]

I installed unistrut on my roof, then mounted panels to that using unistrut L brackets. Each strut has lag bolts with leveling sealant applied before bolting and on top. I wish I'd added a strip of eternabond tape under the end points.
I'm going to go back in the spring and run a strip of sealant tape along the high side of each strut just to encourage runoff and discourage wicking.

I also considered using structural aluminum - 80/20 makes a style that can be mounted to a roof and will curve with it. In the end I like the unistrut.
I'm considering swapping in some 300+watt panels this year and the unistrut will make that very easy.

I considered Unistrut or Superstrut for the same reason but I've already got more in this system than I planned. I have 180W panels. I doubt I'll replace them soon. If and when I do, the few holes they leave won't be hard to cover with a bit of sheet aluminum and a bit piece of Eternabond. I already did that when I moved the roof gland from the original location, and it's a big hole.

 

[DIDDLYV]

not to hijack but I am planning on using strut channel to mount my panels. Is there any utility to putting rubber washers under the strut channel to allow water to drain or just let the natural for and aft slope of the roof take care of drainage?

 

[willo]

I haven't had issues with mine, I have been tempted to add a strip of eternabond along the high side of the unistrut.
If you want to do this, I suggest cutting some blocks of HDPE or PVC fake wood as spacers.
My only regret was not adding a strip of eternabond at the ends of the unistrut. I haven't had any issues, but it looked like a great idea.

Oh, space it enough - if you don't, some minor flexing could have the edge of the strut pushing into the roof material during events that cause flexing - RVs are vibration rich environments.

 

[GuardianZX9]

I am using these, 3D printed, super strong, very lightweight and cheap to print if you are able.

No screws through the roof, silicone mounted, 2 screws for each corner, there are also center mounts I
have not installed yet.

I have the STL's if there is any interest.

 

[willo]

DAMMIT. Somehow I never thought of this.
I would probably use carbon reinforced filament, but that is purely my opinion.
Please put that up on thingaverse so it's easy to find!