We have published many posts on the myths, inaccuracies, and outright lies that some competitors talk about during sales presentations. When we bust the myth, they tend to move on to another scare tactic. Here one you might hear that has been used extensively recently:
“They use a plastic header clamps and ours is metal.”
So? Yeah. And?
I guess the tactic is intended to make you think that we use some cheap plastic clamp and they have a robust metal clamp, and that is somehow going to make our panels fly off the roof. Here is the truth:
- Our header clamps are made from an injected molded polymer that is the same composition as our panel header tubes with added glass component for extreme strength and UV resistance. The header clamps have been tested and are much stronger than required for the loads imposed. Just like all systems, a licensed engineer is required to sign and seal engineering drawings certifying that the system installation method and materials meet Florida Building Code.
- Header clamps (in all systems) are intended simply to keep the panels from sliding down the roof. The wind uplift loads are very low on the header clamps (the straps take the vast majority of wind uplift loads). The physics are pretty simple. On a pitched roof with an angle typical of Florida homes, each header clamp is only required to hold approximately 10 pounds of weight (it’s actually less because I am ignoring friction). For you engineers out there, I’m basing this on 50 pounds with a 23-degree angle roof with two header clamps, so: 50lbs x sin(22º) / 2 = ~10 pounds.
- After Hurricane Irma we found exactly ZERO broken header clamps in any of our installed systems. It simply is not an issue because the header clamp sees very little load.
- Our header brackets are not tight to the header tube, allowing expansion and contraction of the panels. As panels heat and cool, they expand and contract laterally. Our competitor’s aluminum header clamps are tight around the header, which does not allow this expansion and contraction. Aside from being tight, the sharp metal edges grab the polymer header tubes as they shift back and forth. The result is the header clamp twists back and forth, eventually loosening the screws and causing roof leaks. Here is video that shows this phenomenon we have seen over and over again:
- Metal (aluminum) header clamps are made from a dissimilar metal from the fasteners (stainless steel). In a corrosive environment, this can cause galvanic corrosion, essentially “welding” the fastener to the bracket, making service or removal difficult.
- The metal header clamps this particular competitor uses raise the header up less than 1/4″, which results in the header tube and rubber couplers to chafe the roof, causing abrasion and eventually leaks on shingle roofs. Our header clamps raise header tubes completely off the roof to eliminate abrasion.
- Our header clamps have raised fastener heads and sealant pockets underneath. This allows sealant to surround the fastener whereas the metal clamp is flat on the bottom and sealant simply oozes out from under the clamp when installed. Aside from the aluminum flashings we use on shingle roofs (nobody else does), these sealant pockets are far superior to the metal clamp sealing capability.
Just ask yourself why every other company uses a loose fitting polymer header clamp. This one competitor is trying to pitch a metal clamp as a competitive advantage, where it is really a serious design flaw in our opinion. The proof is in the pudding.
A side note on expansion and contraction: aside from our header brackets allowing lateral movement, the polymer used in our panels has the lowest coefficient of expansion on the market, meaning our systems have less movement from side to side, reducing the impact of thermal variation.
This whole nonsense about metal brackets being superior is just a scare tactic. They are trying to spin a negative into a positive. Common sense and evidence win the argument every time. Don’t let them scare you – reject the sales rhetoric in favor of physics and sound solar design practices.