Hurricanes and wind are frequent concerns among those seeking to install solar panels in Southwest Florida, and many people have heard about Miami-Dade hurricane wind code requirements. It stands to reason that people want solar panels installed that meet the most stringent hurricane wind building codes in the country. The concerns usually involve roof leaks and integrity of the roof itself. We saw Hurricane Charley pass through the area a little over 10 years ago with 150 mph winds, making it a strong Category 4 hurricane and at the time the second most powerful to hit the U.S. since Hurricane Andrew in 1992. From that experience, we know what the likely outcome will be when strong hurricane winds hit homes with solar panels.
What many people are familiar with and refer to is what’s called Miami-Dade Product Approval, which is required for certain products installed in the Miami-Dade High Velocity Hurricane Zone (HVHZ). Approved products receive a Notice of Acceptance (NOA) from a testing agency. However, that does not apply to solar panels because they are considered “components and cladding” that do not form part of the building envelope, or main wind-force resisting system (MWFRS). That is, solar panels do not protect against wind and water intrusion into a structure, and do not provide support and stability of the overall structure of the building. Technically, no roof mounted solar panel system “complies” with Miami-Dade Product Approval because no testing requirement exists and NOAs are not issued. The only solar panel products that require NOAs are solar attic fans and roofing systems with integrated or laminated solar electric panels, because these form part of the building envelope.
What is required for permitting solar panels anywhere in Florida is that the system meets the Florida Building Code. The 2010 Florida Building Code is now the effective code, and this requires that solar panels (components and cladding) meet wind loads that are imposed upon them. Solar panels must be firmly attached to the building and have enough attachment points to resist wind uplift. The weight of solar panels is negligible and rarely needs to be considered. In most of Southwest Florida, the ultimate design wind speed is 160 mph. In Collier County there is a large area that requires 170 mph, and Marco Island is 172 mph. Using calculations in accordance with ASCE 7-10, engineers determine the wind uplift at any given attachment point and ensure that the attachment method resists the required load at the design wind speed with a safety margin.
In other words, we have the same requirements that Dade County has, which is to meet the local wind speed requirement. This is done by selecting the proper number of tie-down straps and/or attachment points to resist wind uplift given any installation location and scenario. The building department reviews our plans and inspects our work to ensure that we have met the requirements of the Florida Building Code.
From a practical standpoint and observation, we know that in a catastrophic hurricane one of a few things will likely happen:
- The entire roof will come off, solar panels still attached.
- Areas of the roof without solar panels will have serious damage that makes removing and replacing the solar panels the best option.
- Like shingles or tiles, solar panels will be torn off the roof, leaving the attachment points in place and watertight.
- Your house and solar panels will be spared even though the neighbor may have catastrophic damage.
None of those options sounds great, but that’s the reality of living in coastal areas of Florida. If your solar panels are damaged or lost as a result of a hurricane, it is virtually certain that you will have other damage to the roof and structure that rises to the level of filing a claim with your insurance company, which should cover the cost of replacing your solar panels (talk to your agent). We have all seen seemingly impossible photos and video that show unscathed homes right next to homes that are brought to their foundation in storms.
The bottom line is that installing solar panels on your roof isn’t really a risky proposition. The same basic risk exists whether you have solar panels or not.
Are there companies that can come and remove the solar panel from my roof before Hurricane Irma hits south Florida?
There are tens of thousands of solar energy systems in the State of Florida, but only dozens of active/sizable solar energy companies. It would be impossible to obtain this kind of service once a storm is projected to hit an area. And solar companies need to protect their own assets and employees as storms approach.
The real question is why would you want to remove solar panels? Your solar energy system, if installed under permit by a licensed contractor, would have been installed to meet Florida Building Code. Building codes here have strict design wind speed requirements. An engineered system installed with quality components can withstand significant weather events. For example, most of Collier County has an ultimate design wind speed of 170 mph and there is a safety factor built into engineering drawings.
However, there are no guarantees of course. Catastrophic winds and flying debris could damage solar panels. In all likelihood your home would sustain other damage in this case and you would be filing an insurance claim anyway. Solar panels would not increase the likelihood of damage, and in fact the fasteners could actually improve the attachment of the roof covering to the building’s structure. If you lose your roof altogether, there isn’t much you can do about that!
We encourage all solar energy owners to check with their insurance agent. Most insurance policies cover solar panels in the event of loss. Make sure you do not have any exclusions or riders that would make your solar panels uninsured, but we have found that to be rare.
Unfortunately, you will have little chance of finding a solar contractor to remove solar panels as storms approach. But you shouldn’t worry about them as much as the rest of your home’s building envelope and especially your personal safety.
Is there a way to shut off the water supply to the roof during a hurricane until it passes and then turn it back on in case there is any damage, then it can be check after the hurricane has passed. If we lose power there will be no circulation. Does this cause problem? It doesn’t seem to be covered in our booklet.
If your system was installed with proper isolation valves (all of our systems are), then yes, you can positively isolate your solar panels. No circulation in the panels is just fine. In fact, we recommend people drain and isolate their systems when they don’t plan to use them for an extended period of time.
Are solar panels for pool heating rated to withstand hurricanes in coastal Pinellas County?
ALL solar panels installed in Florida must meet the Florida Building Code, which includes the most stringent wind ratings in the country. It’s not so much the panels, which do have pressure ratings for uplift and downforce, as it is the installation method. The components that hold the panels down to the roof need to be engineered and installed to withstand the wind uplift required in your area. Your design wind speed is less than we have down here in the Fort Myers area, so there is no reason you can’t meet the required wind speed. Just choose a reputable installer that uses quality equipment and adequate straps to meet the building code.
There is no such thing as hurricane-proof – not for solar panels, and not for anything else. In a catastrophic storm, nothing is safe. But that is no reason to avoid solar panels. It’s just another component of your home. For example, we had a client that had both a solar pool heater and an electric heater that went through Hurricane Irma. The solar panels were fine, but a tree fell on the electric heater (and pool equipment). You just can’t tell what mother nature will do.
Jason I am concerned as I keep hearing about 170 MPH wind anchoring to roofs but I can not find any where the details are of the proper anchoring. So can you give me and your viewers the details for 170 MPH fastening and systems of framing that will hold up against 170 MPH winds
thank you from myself and the rest of your viewers
There are so many variations and options, it is hard to answer your question without specifics. I will try my best given the limited information I have. The most popular roof type is shingle. For shingle roofs, we use a product called L-Mount from Quick Mount PV.
The way the engineering is done requires the calculations from ASCE 7-16. The wind loads imposed on a solar array have been determined from extensive testing by ASCE. The different areas of a roof, depending on whether it is flat, hip, or gable, have different calculations to determine the pounds per square foot of uplift imposed on the array. Once you know the pounds per square foot in any given roof zone, you can determine the point loads on any attachment point depending on the spacing between those attachment points. Tests have been performed to determine the pull out strength of fasteners embedded in wood (i.e. trusses or decking).
So, for example, the L-Mount with the manufacturer supplied structural screw, with safety factor applied, can withstand 756 pounds of uplift when embedded 3 inches into a truss. If the ASCE 7-16 calculations yield a 50 psf uplift value in a given roof zone, the attachment will be able to support 15 square feet of solar panels. The minimum number of attachments and spacing is calculated based on this requirement. There are also other railspan limitations and cantilever limitations to consider. This is all worked out between the manufacturers engineering data and the professional engineer’s calculations.
This is just one of many attachment types and strategies for determining the viability of an attachment method. We have a test rig in-house that tests the actual fastener or mounting assembly pull out strength. We can install multiple test fasteners into a given roof and determine the amount of uplift that a fastener can withstand before failure. This is often the strategy used with decking only attachments, particularly on commercial flat roofs. There are destructive and non-destructive test methodologies that allow us to confirm whether a given attachment method is sufficient.
Ultimately, the engineering and test methodologies employed can’t cover every scenario. But experience tells us that systems are generally “over-engineered.” The attachment is often not the weakest point in the system. The panels themselves or the panel clamps will fail before the roof attachment point, which is actually a good thing. This preserves the waterproof integrity of the roof.
We have spectacular anecdotal information having recently gone through Hurricane Irma. This powerful storm did not cause catastrophic results to solar panels in Southwest Florida. There were isolated incidents of poorly installed systems, as you might imagine. But the vast majority of solar panels that needed to be replaced were caused by flying debris or because roofs needed to be replaced while the solar panels remained unharmed. Fears about solar panels causing roofs to leak after a major storm event were clearly unfounded. Tornadoes that have struck the area in recent years provide a better indication of what happens in catastrophic wind events. I am not aware of a single case where solar panels caused a roof to be destroyed or leak. There were many cases where the roof suffered catastrophic failure and the solar panels were damaged as well. But that is all handled through insurance deductibles that would have been necessary anyway.
I hope this answers your question. If you are in our Southwest Florida service area and would like to discuss this further, please let me know and I will be happy to set up a phone call with you. The “roof over your head” is a peace of mind issue that causes a lot of people to reject solar panels, but the overwhelming evidence says that these fears are unfounded.