Here is my 10 step guide on how to mount solar panels to an RV roof.
This article will show you how to securely attach your solar panels with no drilling or mechanical fixing into your RV roof.
I have tried a few methods of attaching things to a camper roof over the years, with varying degrees of success. The method below is my favorite method by far for lightweight applications.
If you’re not convinced by the VHB tape method, I have detailed another no drill method using a marine adhesive sealant.
Contents
Tools Required
Tape Measure
Metal Ruler
Pencil
Scissors
Seam Roller
Socket Wrench or Spanner Wrench
4″ Grinder (fitted with metal cutting disc) or Hacksaw
Metal Paint/Spray
Industrial Wipes
A Word On Tools
There are no specialised tools required for this method. Anything that you don’t have is cheap and readily available from any good hardware store. A tub of industrial wipes is always a good idea on a project like this. I use Everbuild wonder wipes, but any will do.
Materials Required
Solar Panel
Solar Panel Mounting Brackets
1 ⅝” x 1 ⅝” Galvanized Unistrut Channel or slotted channel strut.
Bolts (Stainless A2)
Fast Fix Channel Nuts
Split Rings (Stainless A2)
Washers (Stainless A2)
Thread Lock
3/4 “ 3M 5952 VHB (Very High Bond) Tape
Sika 291i Marine Adhesive Sealant
Exterior sealant (white)
A Word On Materials
Unistrut is a brand name for slotted channel strut, which most good hardware stores will stock. Make sure the strut you buy is the galvanised sort. (Most is).
Solar panel brackets generally come with the solar panel, if not, you can easily find solar panel fixing brackets online.
When it comes to exterior fixings, always use stainless A2 or marine grade A4 nuts, bolts, split rings and washers. Fast fix channel nuts are available in stainless but are quite hard to find. Don’t worry if you can’t find stainless as all fast fix channel nuts are galvanised and won’t rust.
VHB Tape
If you are having concerns about mounting a solar panel to an RV roof with “tape”, don’t.
If applied correctly, 3M 5952 VHB Tape has one of the strongest bonds there is. It can withstand temperatures from – 40°C up to + 66°C. (- 58 °F to 150 °F).
It is resistant to UV, chemicals and moisture.
Read the 3M Data Sheet here.
Sika 291i Marine Adhesive Sealant
Although the VHB tape method would be my personal choice, you could also mount the struts to your roof using an industrial grade marine sealant adhesive – Sika 291i.
This sealant adhesive is extremely strong and will do the same job as the VHB tape. It’s not instant and your struts will require some form of taping to hold them in position while the adhesive cures.
Either of these methods is more than sufficient to mount solar panels to an RV roof and will last indefinitely.
Step 1 – Fix Brackets To Panel
The first thing to do is to fix your mounting brackets to your solar panel.
Bracket Orientation
When mounting solar panels to an RV roof I always turn the brackets upside down.
The reason for this is to reduce the clearance from the roof to underside of the solar panel.
Mounting the bracket upside down brings the clearance down to roughly 3/4 “, if you mount them the correct way up the clearance is about 3”. This is fine for stationary applications, but a lower profile is preferable on an RV roof.
There should now be a bracket on each corner of your solar panel.
Step 2 – Cut The Unistrut
Now we are going to cut your Unistrut to length. Measure the length of your solar panel and add 2” to each end.
Length of solar panel + 4” = total length of unistrut.
You can cut the Unistrut by hand with a hacksaw, but I like to cut this stuff with a 4” grinder and a metal cutting disc. (Mainly for all the noise and the fountain of sparks..)
Step 3 – Attach The VHB Tape
This is the point where you attach your VHB tape, if you have decided to use Sika 291i adhesive you can skip this step.
Clean And Prep The Surfaces
I cannot stress enough how important it is to clean and prep the surfaces where the VHB tape (or Sika 291i sealant) is going to be attached.
To make the bond as strong as possible, use a very fine scotch-brite pad on the roof where the struts are going to sit. The micro scratches made by the pad will help create a much stronger bond. Repeat this process on the bottom of your struts.
Using rubbing alcohol or mineral spirits to clean the underside of the strut and the area of the roof thoroughly where the struts are going to be sited.
Because the VHB tape only comes in certain widths you will have to attach two 3/4″ strips of tape to the underside of the strut. I like to leave two or three 6” gaps in the tape rather than one continuous strip. The reason for this is that it allows for a little bit of water drainage rather than water sitting against the whole length of the strut if it gets wet.
Tip: Once the tape is in place, use a seam roller to firm the tape down. This creates a really good bond.
Step 4 – Paint
The painting is optional, but I think it’s a much better job if you do.
Use a decent quality metal spray paint in white.
A couple of coats is usually sufficient. (Obviously don’t spray the taped side)
Step 5 – Unistrut Placement
Assuming you have allocated a spot for the solar panel on the roof of your RV, we are now going to mark the position of the unistruts on your roof.
Place your solar panel in the spot you have allocated on your roof, and with a pencil mark the holes in the brackets on the roof.
Move the panel to a safe place.
Draw two parallel lines slightly longer than your Unistruts between your bracket hole marks.
The lines should now denote where the centre of your Unistruts should lie.
Step 6 – Attaching Unistrut To The Roof
VHB Tape Method
Ok we’re now ready to attach the Unistrut to the roof of your RV.
Measure and mark the center of the Unistrut at either end.
When attaching VHB tape, always pick a decently warm day, as the adhesive works so much better. If you do attempt it on a cold day, heat the roof area up with a hairdryer beforehand.
N.B. Once this tape touches the surface it is ridiculously hard to get off. When placing the Unistrut, having a helper is a good idea.
Carefully peel the backing film from the tape.
Line up the marks you made on the ends of the Unistrut with the lines on your roof, making sure the Unistrut is where you want it to be.
Place the Unistrut down and press down hard along the whole length.
Sika 291i Marine Adhesive Sealant
As with the tape method, a helper will make this part a lot easier.
Squeeze a bead of sealant down both sides of the underside of the struts.
(Leave an occasional 6” gap for water drainage)
Line up the marks at the ends of the strut with the lines on the roof.
Bed the struts down and use a silicone finishing tool to finish the sealant that has squeezed out. Use some masking tape to secure the struts in place while the sealant cures.
Step 7 – Attach 2nd Strut
Repeat this step for the second strut, making sure that the ends of each one are ninety degrees to each other.
Step 8 – Sealant Around The Struts
(If you opted for the Sika 291i sealant method then this step should already be done.)
Now the struts are down, run a bead of good quality exterior sealant around the struts.
Don’t put any sealant where you left the gaps in the tape.
Step 9 – Fast Fix Channel Nuts
Push the fast fix channel nuts onto the strut. You may have two holes per bracket, you may have one, it just depends on the brackets you have.
Slide as many channel nuts as you need onto the strut, roughly in the right place.
Step 10 – Mount Solar Panels To RV Roof
Place your solar panel on the struts, making sure you can access any wiring for connecting later.
Now line the channel nuts up with the holes in your brackets.
Put a split ring on each bolt, then a washer and for good measure I like to use some thread lock as well.
Put the bolt through the bracket hole and tighten into the channel nut with the appropriate size wrench or socket.
Repeat this for all the brackets.
Congratulations! You should now have a solar panel securely mounted to your RV roof.
This method is a tried and tested way of robustly mounting a solar panel to an RV roof without drilling into your roof and using mechanical fixings.
For peace of mind you can always periodically double check the strut bond to the roof, but in my experience, if done properly, this method is more than sufficient for the job.
FAQ’s
Do I Need Specialist Tools For This Task?
No, specialist tools are not needed to complete this task. However, a decent DIY skill level will be an advantage.
Please check out my other maintenance guides.
