why do u avoid if flat tile roofs are involved? TSLA cuts costs by standardizing no salesman etc too.
There isn't really an ISO standard for flat concrete tiles for roofing. So the tiles really aren't all identically shaped (thickness, dimensions, etc) from house to house or year to year. The tile hooks all kind of rely on the tiles having some space to sneak around and form the "hook" so the part can be lagged to the rafter, but still provide a mounting surface for the racking L-feet.
A roofer who has been active for the other homes in my HOA (and other nearby developments) says he's seeing an issues where the hooks are coming in contact with the flat tiles and causing damage over time. S and W curvy tiles tend to fare better since installers can shoot for the dip in the tile and there's more clearance.
While not all solar tile hooks are the same, they pretty much all operate with the same principle. SnapNRack literally shows a picture of the problem on their own webpage:
SnapNrack introduces the Flat Tile Roof Hook. The hooks are a strong, low-profile roof attachment solution for flat concrete roofing. […]
snapnrack.com
You can see the hook is literally sitting on the course of tiles below it. And the tile above it is literally sitting on the hook. SnapNRack is owned by Sunrun while Zep is owned by SolarCity/Tesla. Zep smartly won't put pictures of their product online when installed on flat tiles. But I'd wager dollars to donuts the same exact problem occurs with their hook on flat tile as well.
Technically installers are supposed to grid a notch on each tile that is near a solar tile hook to prevent the hooks coming in contact with the tiles. But that's simply not happening as installers get pressed for max-speed to operate on razor thin margins. Plus a ground-down tile is naturally going to be less strong over time.
I agree, the tile hooks are pretty thick, so you're not bending one with your hands (at least I can't since I'm a wimp). If you hold a tile hook in your hand you're probably thinking it's going to last forever. But imagine these hooks being affixed under a big solar array and getting years of strong gusts ... the array will exert force up and down on the hooks for years as well. So over time the hooks can crack the tiles they're resting on. Yes, your underlayment may still protect against leaks, but now you're at more risk for leaks because there is no flashing anywhere near the broken tile.
Some homeowners also complain about the upper course of tiles rattling since they're seated on the hook.
There's a way to get the mounting done using flashing above and below the tile after they put a hole through the tile for the stand-off mount. And they use mastic to seal the ever living hell out of the penetrations. This method won't leak because of a lag-penetration when done correctly. Even if the tile is compromised with the hole, the top/bottom flashing keep water from getting near the penetrations. The QuickmountPV flashing/method shown here even has the top flashing stamped with the cone so water has to rise up pretty high to even get to the bead of M1 they put on. This approach simply isn't leaking over time due to Solar because nothing moves and there's flashing everywhere..
Yes, this way is uglier, but no, I don't care about ugly. I care about a future leak and finger pointing over who is at fault. I had a roofing guy inspect the solar just to look for some shoddy work and clean out my gutters. He says things look pretty good. So at this point, if there's a leak, I'm 99% sure it's going to be because of my aging roof or a skylight. I'm not even going to try and finger point to the solar having caused the leak.
Edit: I had one local installer say they use the IronRidge Knockout tile replacement mount. If you have flat tiles, do NOT go with this option.
Same roofer that says he's seen issues with hooks also say this knockout tile replacement is prone to leaking. The EPDM collar basically sits on the same plane as the flat tile. If you watch the video, you can literally see the fake 3D animated water flow down on the tile replacement and intersect where the knockout is made and the L-foot is mounted flush. He said these things leak like crazy when the EPDM collar corrodes and there's no protection under this knockout tile. This IronRidge flat tile replacement knockout thing is way worse than tile hooks.
