How To: Mount Panels to an RV Roof

Whinny

Solar Enthusiast
My first panel install isn't done quite that way-it took muddling up one to get the brain working. The next 5 used 1x2x1/8 aluminium angle 4" long. Lots of options on layout and height from the roof.
 

DIDDLYV

New Member
I will be mounting 4 210 watt panels to my 5th Wheel. Plan on using strut channel and tilt brackets for ease of access and improve air flow underneath.
 

Pitownpi

Solar Enthusiast
Step 10: Install The Fasteners
Using a drill with a hex head bit, install the hex head screw. Press down firmly on the drill so that the tip of the screw quickly pierces the EPDM and goes into the roof decking and then the truss. Do not over tighten the screw. This is especially important for those screws that won't be going into the truss. I used two screws per bracket even though only one was going all the way into the truss. Make sure the head of the screw is flush with the bracket.

Installing the fasteners will cause the Butyl Tape to squeeze out a bit. That's normal.

View attachment 22987
 
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Pitownpi

Solar Enthusiast
Did you pre drill, or just drive the #10 screws in?
#10=3/16", I've got some really nice #14 (1/4") self tapping metal to wood screws with a sealing washer backed up with a metal washer. They are for fastening metal roofing down. They fit perfectly centered in my bracket holes. I'm thinking a small pilot hole should be drilled in order to ensure the deck won't split.....I'm using two piece brackets. I've already had the panels up on the roof, screwed down with some smaller self tapping screws then took them off. Plan is to now just install the bottom foot of the brackets, using the butyl tape as you did, did it on top. then I'm recoating the roof. Then I'll go up and install the panels with upper portion of brackets matting up to the lowers.
The lower brackets have four holes, they are a good 3-4" inches long. I was thinking to even use all 4 holes, maybe #8s in the middle 2, and the #14 in the outer 2 holes...that would be 4 holes in the roof for each bracket. 8 brackets per panel....3 x 80"x40" 400 watt panels.....hmmm now that I think about it maybe just the 2x#14 screws will be fine..
Only hitting the outside roof edge as far as trusses is concerned, and maybe one on inside edge. Roof Plywood seems 3/8"-1/2".
 

Dalton Bourne

New Member
Pro-Tec Pro-Strength is another outstanding, high-quality product worthy of your consideration. It gives me confidence that this product will do what it’s made to do. This product comes with the inclusion of both a cleaner and a protectant, which is a feature I love. This product protects the roof from those UV rays that can cause so much damage. Also, it does a great job getting rid of the substances that often end up on top of your roof: tree sap, grime, bird droppings, etc..
 

Dalton Bourne

New Member
Pro-Tec Pro-Strength is another outstanding, high-quality product worthy of your consideration. It gives me confidence that this product will do what it’s made to do. This product comes with the inclusion of both a cleaner and a protectant, which is a feature I love. This product protects the roof from those UV rays that can cause so much damage. Also, it does a great job getting rid of the substances that often end up on top of your roof: tree sap, grime, bird droppings, etc..
 

Stepandwolf

Solar Enthusiast
Glad I found this discussion as I have been thinking about it for a year. In that time I have seen many different methods. My first preference is one that only goes into trusses, which means using rails vs having the size of the panel dictate installation.

I have seen the channels sold at the lumber yard, but am strongly considering 1.5" aluminum box tubing. With my layout, I have a 144" and a 177" space down the sides of my TT. I will have rails that will run full length, cross rails and legs at every other truss. The legs will help me keep the rails at the same height by having a longer leg on the outside. I can also use the rail system as part of a tilt system if I later decide to go that route. The rail system will allow me to run the cables on the underside, off the roof. There is space on my small 22' TT for ten 100W panels.

Haven't thrown my plan out there before so you guys are my first audience.
 

HRTKD

Boondocker
Why do you want the rails at the same height? Are you trying to get the panels mounted so they are all flat and pointing the same direction (up)?

I have some thoughts on this, but I want to understand your goal before saying anything.
 

Stepandwolf

Solar Enthusiast
Why do you want the rails at the same height? Are you trying to get the panels mounted so they are all flat and pointing the same direction (up)?

I have some thoughts on this, but I want to understand your goal before saying anything.
If you don't know which way your roof is going to face, then straight up is preferred. I am following a guy who put panels all over his roof, but also put one flat on the side for December sun.

I am not the guru of flatness, but it seems like it is better to be half right all the time. :)
 

HRTKD

Boondocker
If your roof has a significant arch, like on an AirStream, you could put panels on opposite sides in parallel. That way, one side catches the morning sun and the other side catches the afternoon sun. If you're parked east/west then it's all good and they all produce equally.
 

Stepandwolf

Solar Enthusiast
If your roof has a significant arch, like on an AirStream, you could put panels on opposite sides in parallel. That way, one side catches the morning sun and the other side catches the afternoon sun. If you're parked east/west then it's all good and they all produce equally.
nothing extreme...I bet not even an inch. The other advantage of the rail system is I can bring all the panels up to the height of the skylights. I don't want to raise them to vent or AC height, but anything they are as high as won't create a shadow.

I also think I will end up with two SCCs so one can be on one side, one on the other which will help mitigate shadow issues.
 

Volt3939

New Member
I see the original OSB was totally rotted out, most likely a leak caused that. Also it indicates shoddy construction by the manufacturer.

If you check a sheet of OSB at places like Lowes, HD, etc. it will have a painted-on label explaining that it is waterproof on the face and the edges as supplied. IF you cut it it is no longer waterproof on the cut edges. You must paint any cut edges before installing it... (I always paint the whole thing myself.)

That said, my trailer is an antique from 1974. It has an aluminum shell over "one by" stick upright frames, with "two by" arched roof rafters. No walking allowed. When rebuilding the roof I needed to cut several of the arched rafters and was struck by how the scrap piece fit on the roof with the same curve. So a few long bolts and a ton of sealing later, I had a platform to mount my panels. Originally I only had three 100W panels mounted to the rails with aluminum strips and some stainless piano hinges so I could tilt them forward when facing south.

Later I noticed a seam along both sides where the sides are screwed to the top, with a drip rail and an awning slot on one side. Saw someone on the web had used that to fashion tubular steel frames with riser brackets screwed into the drip rail screw locations. I did the same but used piano hinges to mount the panels to the frames on the leading edge, mostly for access under the panels since tilting them up would shade the other row of panels.
Later I added another pair at the back that uses a steel frame at the rear and one of the rails on the front side. I also added a pair of 50W flexible panel at the front on either side of the front vent, but one has already failed. (That little white triangle a the front is where I fit the 50W that failed.)

Solar Trailer 1 crop.jpg
 

HRTKD

Boondocker
I see the original OSB was totally rotted out, most likely a leak caused that. Also it indicates shoddy construction by the manufacturer.

Plenty of shoddy construction in my trailer. I put a new sheet of fiberglass on the front wall today. The morons at the factory installed the fiberglass on top of the EPDM where they meet on the roof. That way, when the molding holding the joined surfaces down to the substrate fails, the water goes right into the trailer instead of staying outside on the fiberglass.
 

Stepandwolf

Solar Enthusiast
Plenty of shoddy construction in my trailer. I put a new sheet of fiberglass on the front wall today. The morons at the factory installed the fiberglass on top of the EPDM where they meet on the roof. That way, when the molding holding the joined surfaces down to the substrate fails, the water goes right into the trailer instead of staying outside on the fiberglass.
I am pretty sure that is how mine is...rubber on bottom, front cap on top.
 

HRTKD

Boondocker
I am pretty sure that is how mine is...rubber on bottom, front cap on top.

Your molding, butyl tape and sealant had better be top notch then. I'm thinking that every piece of aluminum molding should come off every five years for cleanup, new butyl tape and new sealant. As a test, take out a random fastener. If the shaft of the fastener is rusted anywhere, then you have a leak and the molding needs to be redone. None of the OEM fasteners on my trailer were stainless steel.
 

Stepandwolf

Solar Enthusiast
Your molding, butyl tape and sealant had better be top notch then. I'm thinking that every piece of aluminum molding should come off every five years for cleanup, new butyl tape and new sealant. As a test, take out a random fastener. If the shaft of the fastener is rusted anywhere, then you have a leak and the molding needs to be redone. None of the OEM fasteners on my trailer were stainless steel.
When I get my TT home, I took this picture so I could start planning solar install. Pardon the stains, etc. on the roof as I purchased the TT the trailer home and had just gotten it back home from the dealer 750 miles away. BTW, I still haven't used the TT or washed the roof, but it is a 9 year old TT and I doubt they ever touched the roof.

You can see in the picture how the front cap is over the roof and a row of large fasteners to hold things together. Are you suggesting that someone remove all that caulking, all those fasteners, and re-do it. I can almost guarantee you I would totally mess it up and would need a pro and I am still not sure the seal would be better after. You can see that it has been re-caulked which the dealer said they did during prep.

BTW, I don't know about all fasteners, but the ones for the Max fans are SS.

front cap.jpg
 

HRTKD

Boondocker
Is that a fiberglass cap or is it just a sheet of fiberglass? Either way, the lap sealant on the molding doesn't look to be in good shape. But maybe it's just the picture. That piece in your picture is what I was working on tonight. It's the primary culprit for the water intrusion that cause a lot of delamination of the exterior fiberglass, as well as a deterioration of the interior paneling.
 
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