A new 5V metal roof requires thousands of screw attachments through the metal.

Solar Pool Heaters | Roof Penetrations | The Truth

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The truth is that regardless of the brand of solar pool heater you choose, to secure them to your Florida roof properly a solar installer must use screws to achieve resistance against wind uplift. This strikes fear in some people, but the risk of roof leaks is extremely minimal. Dealers (and the industry as a whole) would not survive for decades if the product and workmanship resulted in frequent occurrences of roofing problems. The industry as a whole has been very successful in developing products and techniques that prevent roof leaks.

A new 5V metal roof requires thousands of screw attachments through the metal.

A new 5V metal roof requires thousands of screw attachments through the metal.

Some roofs, like metal 5V crimp roofs, have literally thousands of screws with EPDM washers securing the metal roof pans to the sheathing. Virtually all roofs have plumbing vents, and most have some form of ventilation system, all which require large roof penetrations. We accept these necessary through-roof holes, so sealed attachments for solar panels should be no big deal if done correctly. That’s not to be taken lightly, because doing it incorrectly can and does result in problems occasionally. Hiring an experienced licensed certified solar contractor is your best defense against shoddy workmanship. You should also check your contractor’s insurance certificate. Insist on a permit where required, which adds not only an inspection by a building inspector, but further assurance that the contractor is licensed and insured as required by law.

The only type of roof that does not require some kind of penetration is a standing seam metal, on which you can attach solar panels with non-penetrating hardware that clamps onto the seams. This method is relatively expensive for a solar pool heater and requires an aluminum substructure. It is rarely used (although for more expensive solar electric panels, this method is commonplace).

There is a misconception (and often a lie) that solar pool heating panels with separated tubes required fewer or no roof penetrations. The truth is that these types of panel often require more roof penetrations. For example, a typical fully body panel system that we sell with nine 12′ solar panels requires approximately 54 fasteners including the body straps. One of our separated tube panel competitors uses alligator clamps with no body straps. On their system each panel requires four clamps secured by two fasteners each. That is a total of 72 fasteners on an eight panel system. The picture below shows this competitor’s product. I took this picture two days ago, and I counted exactly 72 fasteners on the nine panel system — 33% more than our full body panel.

Heliocol Panels Require More Roof Penetrations Than FAFCO Brand Solar Pool Heating Panels

Heliocol Panels Require just as many Roof Penetrations as other Solar Pool Heating Panels because of top an bottom clamps with multiple fasteners per clamp.

The figures above do not include additional fasteners required to attach plumbing. Since our systems allow same-side feed and return plumbing, our plumbing runs are typically much shorter, requiring fewer fasteners.

The total number of fasteners required depends on an engineering calculation considering the location of your home and proximity to open spaces, especially large bodies of water. Ultimately we are splitting hairs between panel brands — whether it’s 54, or 72 fasteners, the bottom line is that you will have quote a few attachment points regardless of brand, and there is little to worry about. We’ve done this… thousands of times.

Selecting a proper sealant is also important. The good stuff costs a bit more, but it’s well worth it. A tri-polymer sealant that will not shrink and crack over time is the best practice. Some popular sealants are not compatible with asphaltic surfaces (as in asphalt shingles or rolled roofing material), so it’s important to make sure the sealant used will adhere to the surface and provide a long-term waterproof seal. I like a product called Geocel 2300, but there are several quality products on the market, some of which are marketed specifically for solar roof attachments. Common silicone or urethane caulk won’t work, so make sure your dealer knows what they are doing.

If you are concerned about roof penetrations, hopefully my final point will help. In Southwest Florida we are required to meet the 2010 Florida Building Code which requires use of ASCE 7-10 for wind load calculations. The design wind speed for most of our area is 160 mph, going up to 172 mph in Marco Island. The codes are quite stringent, and if we experience winds in excess of these, catastrophic property loss will be you main concern, not your solar pool heating panels. With the exception of catastrophic wind events, solar panels are designed to stay on your roof firmly without any roof penetration problems. We can’t control mother nature, but we can install your panels to meet all instructions and codes!

Comments

  1. So I’m reading this article, go for next Thursday I plan on getting it as a metal standing seam roof, so I don’t have to worry about Leaks for a long time, are you saying that doesn’t need any holes in the roof for a solar pool heater with metal attachments on the seams, but that requires an aluminum substructure? What is that? And what I need that for photovoltaic panels on the same roof as well?

    1. Author

      For solar pool heating, the aluminum substructure is a series of aluminum c-channel rail mounted on standing seam roof clamps. The clamps are attached to your seams using bullnose set screws that do not penetrate the metal. The rails go horizontally. The panel mounting hardware is mounted on the rails. Frankly, it’s not a great solution. It is relatively expensive when considering the cost of a solar pool heater.

      Solar photovoltaic systems on a standing seam roof are a piece of cake. The same clamps are used. Then you mount traditional solar PV rails on the clamps. In most cases, this is no more expensive than a shingle roof and less expensive than a tile roof. While the material costs might be higher depending on how many clamps you need, the labor savings offsets that. It’s absolutely a great scenario for solar photovoltaic systems. Keep in mind there may be one penetration per roof face to get conduit into the attic, but even that can be avoided in many cases. And that penetration is at least as solid as any other plumbing vent or gooseneck vent.

      I hope that answers you question.

  2. Why is having pool solar on metal roof with rails not a great solution, yet solar photovoltaic are a piece of cake ? We need ideas, have 7 solar panels sitting on patio and a new 1″ standing seam roof that we do not want to ruin with the many screws to reattach it. Sadly, will loose so much money by not using these panels. Unless there is a market for used panels. They are 2 years old.. Then we will have a cold pool again. Very sorry situation.

    1. Author

      Kathy,

      Solar pool heating panels are flexible, not rigid like photovoltaic panels. They would sag between rails, which means you need a lot of rails to support them. You also need a lot of attachment clamps consequently. The cost of the aluminum rail substructure and attachments would cost about as much as the solar pool heating panels themselves. That is not the case with photovoltaic panel systems, which can easily be 10 times the price and use fewer rails. It’s just not a practical solution.

      We see lots of people switching roof types without considering the impact on their solar energy system. It’s unfortunate for sure. Metal tiles are another problematic roof type that people are surprised to find out about.

      There is no market for used solar pool heating panels. They can’t be sold with a warranty and the handling of them during removal and reinstallation can become a service problem. The panels themselves also make up a very small percentage of an installed system cost, so there isn’t much value there.

      I’m sorry you are stuck with these used panels due to your new roof type. You might consider selling them on Craigslist, but I would not expect to get a whole lot for them.

      1. Author

        Hi Vivian,

        Steep metal roofs can be challenging. It sounds like you have a different issue from Kathy. A standing seam metal roof is different from a 5V metal roof or other corrugated profiles or R-panels. It may simply be that the installer is not equipped to work on metal roofs over a certain pitch or your roof is simply too steep for anyone to effectively install this type of panel on it.

        Jason

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