Why solar pool heating panels slide off a roof is usually due to poor installation hardware or practices. Solar panels should be securely affixed to your roof surface for the lifetime of the system with hardware made to withstand the elements. Sometimes we find solar panels hanging off a roof or falling down when a homeowner reports something doesn’t look right.
The pictures below are a competitor’s system that uses a “Z-bar” where plastic clips act as header clamps that are supposed to keep the panel securely fastened to the roof. There are multiple problems with this installation hardware that were discovered long ago. The first is that the metal Z-bar causes water to dam up above it and can cause roof leaks. Debris also gets trapped in the lip above the metal bracket. In addition, the plastic clips that hold up the headers have a tendency to fail, breaking off and allowing the whole system to slide down the roof.
In these pictures you can see that the panels are just hanging on be a thread, with the plumbing holding things together for now. The remedial action would require disconnecting all of the plumbing, moving the panels back up and securing with replacement clips, and re-plumbing the sections of badly bent pipe. It’s a major job, and we didn’t recommend it because we couldn’t guarantee that the system would not leak once it was back in place. Furthermore, we would have had to use the same inferior clips that would likely just break again.
Now in fairness, this manufacturer has changed their installation method in favor of a header clamp, but their clamp design also has a major flaw where the latch that holds the two parts together tends to get brittle and break off. Once the latch is broken, the clamp provides no resistance to wind uplift, and can be removed very easily without tools. While that makes our job of removing and replacing their systems very easy, it’s bad news for people who have those systems, and they are still using the same clamps!
Other manufacturers have different issues including broken header straps, fasteners pulling out of the roof altogether, and various workmanship issues that cause header brackets to twist with expansion and contraction.
To prevent these issues, we use a two-piece header clamp that cradles the panel header above the roof surface, allowing the system to expand an contract laterally. The slide-in bracket channel requires no latches, hooks, or hardware to secure the two parts together. They just snap in place and securely hold the panels up. We also use a minimum of two clamps per panel, and two fasteners per clamp to eliminate twisting. We also have an exclusive aluminum flashing method on shingle roofs that greatly improves leak-free performance on your roof.
There is no substitute for the right materials installed the right way. People often buy solar panels based on price and find themselves regretting their decision. It doesn’t cost much more to get it done using the best available materials and workmanship. If you find your solar panels sliding off of your roof, contact us so we can help evaluate your options.