I get why inspectors want everything exposed, but honestly, it feels like overkill (and a money pit) if you’re working with a roof that’s not ancient. When I did my addition, I tried to just patch what looked bad, but then the city made me rip out all the old flashing anyway. Kinda frustrating when you’re trying to keep costs down. Has anyone managed to convince their inspector to let them keep existing stuff if it looks solid? Or is it just a lost cause with green roofs?
I get the frustration—nobody likes tearing out stuff that looks fine just because a rulebook says so. But honestly, have you ever seen what happens when someone skips that step and then a leak pops up under a green roof? Total nightmare to fix after the fact, especially since you’re adding all that weight and moisture up top. I’ve tried showing inspectors photos and maintenance records to prove existing flashing was still solid, but no dice. Maybe it’s just the liability thing for them... Still, I do wonder if some cities are stricter than others about it. Has anyone actually gotten away with leaving old flashing under a new green roof without issues down the line?
I get where you’re coming from, but isn’t there a case to be made for keeping existing flashing if it’s in good shape and matches the new waterproofing details? I’ve seen a couple of projects where the old flashing was left in, and as long as they tied the new membrane in properly and double-checked for corrosion, it held up fine. Maybe it depends on roof slope or climate too—like, would a dry area have less risk than somewhere with freeze/thaw cycles? Just seems like a lot of waste sometimes when the old stuff still works.
Leaving old flashing in place can work, but honestly, I’ve seen it bite people later—especially with green roofs. Even if it looks fine now, older flashing can have hidden pinholes or fatigue you won’t spot until there’s a leak under all that soil and vegetation. Once you’ve got a green roof installed, tracking down and fixing leaks is a nightmare.
Climate definitely matters. In dry areas, maybe you get away with it longer, but freeze/thaw cycles are brutal on metal. Expansion and contraction will find any weak spot. I inspected a job last year where the original copper flashing was reused—looked perfect at install, but two winters in, water started seeping behind the membrane because of tiny splits that weren’t visible before.
I get not wanting to waste good material, but with the extra weight and moisture from a green roof, I’d lean toward new flashing every time. It’s just not worth the risk or hassle down the line if something fails under all those layers.
Once you’ve got a green roof installed, tracking down and fixing leaks is a nightmare.
Can’t agree more. I’ve seen folks try to save a few bucks by keeping old flashing, only to end up ripping out half their green roof to chase a leak. It’s just not worth the gamble, especially in places with wild temperature swings.