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Most RVs have rubber roofs made from EPDM or TPO, with the rubber sheet set over wood or another material. The question is, can this hold up solar panels? Or do you need to add additional components to provide support? Actually you can put PV modules on rubber roofs, but it must be done properly.
Solar panels can be installed on a rubber roof with lag bolts and a sealant. A ballast mounting system can also be used to keep the solar panels in place.
Solar Panel Mounting on a Rubber RV Roof
Solar panels can be installed on a rubber roof using lag bolts. Connect mounting brackets on the panel frame and fasten to the roof, after which you apply Dicor or another sealant around the holes. For flexible solar panels, use the adhesive suggested by the manufacturer and stick directly on the surface.
Your solar mounting hardware provides directions for installation. Basically you hook up the solar panel frame to the mounting brackets and connect these to the roof. The required hardware should be included in the kit so install as directed. Note that the hardware will be different if you opt for a tilted solar panel.
Carefully align the solar panel during installation. Make sure there are no obstacles around the panel and there is space to clean the modules or for troubleshooting.
Most solar mounting kits have Z brackets and it works fine for rubber roofs. Tilted hardware is also available and you can even order custom brackets. For most though a Z bracket set is sufficient.
Once the panel is secure, apply Dicor around it. This sealant is widely used because it works well with solar panels, but you can use other sealants provided they are strong enough.
You cannot use VHB tape to install solar panels on a rubber roof. The rubber is a sheet, and if the glue comes off the sheet might get pulled off as well. For rubber roof – on an RV or any other structure – you should use lag bolts.
Mounting Flexible Solar Panels on an RV Rubber Roof
Mounting flexible solar panels is even easier. Use whatever adhesive is suggested for the product and stick it on the roof. No need for lag bolts or any screws. These adhesives have a very strong bond so once it is in place the panel will be very hard to remove.
A quick note about flexible solar panels. Because these panels are bonded on the roof, there is no gap between the module and roof. Ideally, air has to flow between a solar panel and RV roof to keep the temperature down. Contrary to popular myth, solar panels do not work better at hot temperatures, in fact performance will dip the hotter it gets as the voltage level goes down.
Modern flexible solar panels are designed to keep temperature around as low as possible. But be aware of the lack of air flow and how it can lead to overheating in certain situations.
Tips For Installing Solar Panels on Rubber Roofs
- Use the screws, nuts and bolts that came with the solar mounting kit. You can buy these at any hardware store, but the ones bundled with the kit are designed specifically for solar mounting.
- Apply a generous amount of sealant. If your RV goes through rough roads or you drive through strong winds and rain, make sure to fortify the panel mount. This is only for flat modules, because you have to fold tilted panels when driving.
- Use a stud finder if possible. This provides extra support for the roof especially when combined with sealant.
- Ask for professional help if needed. If you are not sure how to proceed, ask a professional installer to do it for you. Installing solar panels is a serious undertaking, so don’t hesitate to seek help from experts.
Can a Rubber Roof Really Support Solar Panels?
This is the biggest question that RV owners are asking. A solar panel weighs 35 to 40 lbs, so if you put 2 of those on the roof, that is 80 lbs or so, plus the mounting hardware.
An RV rubber roof can support the weight of solar panels if there is sufficient structural support beneath. Modern and solar ready RVs have robust roofing designed to hold up solar panels. So if you have a new RV you don’t have anything to worry about, but older models have to be inspected.
There is a lot of debate as to which is better, EPDM or TPO , but as far as solar panel installation goes it does not make much of a difference. What matters is there needs to be a thicker layer of wood or other material under the rubber, otherwise the sheet will not hold.
Things to Do Before Mounting Solar Panels on Rubber Roofs
These tips are applicable not just to rubber roofs, but any solar installation, be it on a house, boat or jeep.
Size your solar power requirements. Once you know how much solar power your RV needs , you can determine if the roof can support the number of modules required. If not, you may have to get another power source or buy a battery bank. You can always start with a small solar system and add to it if necessary later on.
Inspect the roof. Check your RV owner’s manual for details on the roofing material. What type of rubber it is, what it is resting on, how thick the support is, how many layers etc. Then contact a solar panel supplier and tell them you want solar power on your RV. Tell them about the roof specs and they will know if it is strong enough or not.
Measure the roof. By measure we mean the available space for the solar panel. Keep in mind that these panels need to be spaced apart so you can step on the roof to clean and inspect them. You should also decide now if you want to install the solar panels in series or parallel.
Buy the components. These includes the solar panels, mounting hardware, sealant and any tools required. You will also need a charge controller, connectors, cables and wires .
Does My RV Have a Rubber Roof?
If the roof is metallic, it is aluminum, and if it feels solid but not metallic, that is fiberglass. Vinyl resembles rubber but it won’t give when you pinch. Your roof is rubber if you pinch and it pinches up.
There are two types of rubber RV roofs, TPO and EPDM. Gray or white streaks along your RV suggests it is an EPDM roof, and EPDM also gets very slippery when wet. TPO rubber looks and feels like orange peel and is glossier compared to EPDM.
Both types of roof work well with solar panels. As long as the roof is solidly built and the panels are installed correctly there should be no problems. However, EPDM and TPO roofs require regular maintenance. Even if your solar panel does not need frequent cleaning, your roof does. Keeping your roof clean helps keep the roof in shape so it helps maintain your panels too.
How to Clean RV Solar Panel Rubber Roofs
Rubber roofs need cleaning every few months to ensure it does not crack. Fortunately the process is easy enough, and it is not that different from cleaning solar panels on rooftops.
How to Clean an EPDM Roof
Put on soft soled shoes when you climb up the roof. Careful to avoid the solar panels and try not to get them wet when cleaning the roof. Unless of course you plan to clean them at the same time.
- Bring a mop and bucket of water on the roof.
- Wipe debris from the roof.
- Mop the roof thoroughly. Use cleaning detergents if necessary. Make sure the detergent is for EPDM and do not let any of it get on the solar panels. You can put covers on the solar panel to protect them.
- Rinse the roof with hose.
Tips and Warnings
- The hotter the weather, the more frequent cleaning is required
- Check the roof for cracks or leaks before cleaning. Fix these before cleaning.
- Caulking should be done once a year no matter the RV roof type
How to Clean a TPO Roof
The steps are similar to maintaining an EPDM roof. Again, consider putting covers on your solar panels to avoid getting them wet.
- Wipe the debris from the roof.
- Clean the roof with non abrasive cleanser and water.
- Rinse the roof with a hose.
Just like with EPDM rubber, check the roof for signs of damage before cleaning. While you are it, might as well look for signs of solar panel problems. Inspection should be done regularly on TPO roofs, much more so compared to the panel itself.
It is possible to install solar panels on RV rubber roofs by fastening with lag bolts, and for flexible solar panels it is as simple as sticking the module on the roof. There are a lot of reasons to use solar power, and having rubber roofs is not going to be an issue.