So guess what happens when someone cuts a 6-foot circle out of your expensive EPDM roof membrane and forgets to flash it right? You guessed it—sadness. Drone landing pads. They’re cool, granted. GPS precision, automated landings between HVAC units, like it’s skynet-lite. But when it rains, it ain’t pretty. We’re talking seepage. Drip lines. Black mold deciding it wants a corner office above your accounting department.
And patchwork ain’t what it used to be. Funny, right? One would think sealing a rubber gasket around a metal disc on a flat roof is just like—eh—slapping peanut butter on toast. But nope. It’s more like trying to butter toast during a hurricane.
Surface prep is a liar
First rule they never teach you: clean is never clean. It looks clean, smells clean, but then… you hit a patch of gravel stub or some sunbaked schmutz and your sealant lifts like a guilty conscience. If you’ve ever mixed modified bitumen by hand in 90-degree weather while pigeons give you side-eye from the parapet, you’ll understand the bitterness in my tone.
Used acetone once. Burned off half my will to live along with the oxidation layer.
The weird part about retrofitting aluminum discs
Those drone pads—they’re often aluminum alloy plates, laser-etched with docking details, markers for onboard cameras. Precision gear, but bolted, glued, or—get this—sometimes just double-sided taped (yes really) to roof surfaces where wind uplift is an actual enemy. Who greenlit that?
So you go to repair the seal, and you realize the pad itself is sitting cockeyed over a minor hump in the roofing substrate. You don’t wanna unseat it, but you know water loves inconsistency. Like raccoons, it finds the uneven bits and gets into ’em.
Used a butyl rubber strip once that stuck better to my gloves than it ever did to the flashing.
Alligatored tar and other sad textures
Found a section last fall where the membrane had cracked like lake ice. Alligator skin, they call it, though frankly alligators deserve better comparisons. Right under a pad that sees three drone landings a day. Vibration stress maybe? Or maybe just bad karma?
Industry says you should cut out the offending membrane and patch over fresh decking. Who has time for that? So you end up torching a mod bit square in there and saying a small prayer to Saint Eligius. Then you question if the drones are worth it—masked sky insects that buzz in then disappear like your ex right before the holiday party.
Roof alligatoring is a phenomenon that occurs as a flat roof ages. In general, it’s caused by the sun. The bright UV rays eventually dry out the membrane or coating that tops your flat roof, causing it to crack. The older your roof gets, and the longer you leave alligatoring to its own devices, the worse it will get. Extreme temperature changes, from sunlight, snow, and even internal heating and cooling will cause new cracks to appear and will make existing cracks worse.
https://wernerroofing.com/blog/what-is-roof-alligatoring-and-what-does-it-mean-for-your-flat-roof/
Don’t trust foam backer rods
Those backer rods, the foam ones, press them into the perimeter joints and they look, sure, tidy. But give ’em a season of freeze-thaw and they shrink into themselves like a shy intern. Water eats them for supper.
Now I wrap mine in UV tape before embedding but that’s probably a superstition at this point. Like knocking on wood, or thinking building inspectors won’t notice your missing third layer of mesh.
There was this time I stood ankle-deep in scupper runoff…
…and still tried to lay sealant. That’s dedication or dumbness, depends who’s telling the story. Snow melt had poured down toward the drone pad slope—it was one of those older buildings where gravity still surprises the architects.
I tried troweling polyurethane sealant while my boots squelched and ducks probably formed committees below. Do not recommend. Should’ve waited ‘til dry weather. But deadlines.
Client said “we’re losing tens of thousands from flooded ceiling tiles,” and there I was, doing slapdash trench warfare around an aluminum hula hoop nailed into place by someone who probably had a marketing degree.
Pseudoscientific solutions people swear by
Heard from a guy in Pittsburgh who uses auto body undercoating as a waterproofing layer around drone pads. Thick stuff. Smelled like 1984 Chevy. But hey, he says it works. Another guy insists on embedding bronze mesh into his synthetic layers to “improve grounding.” Probably read it on a pilot forum filled with people who think hovercrafts and ley lines are connected.
I tried neither. But honestly? I’ve done weirder. Like using a kitchen spatula to shape fast-set mastic when my usual tools froze. Adapt or go soggy, that’s the roof motto.
In closing, or actually, not really closing
There’s not really a bow to tie neatly around this. Drone pads on commercial roofs are gonna keep multiplying. And most roofs weren’t designed for ‘em. They weren’t thinking about vibration loads. They weren’t thinking about exact deceleration zones or battery acid seep. It’s new territory but landmined with old systems.
I keep two buckets on me now. One for patch material. One for resignations.
Also, always mark your repaired seal edges with red chalk—saves some poor tech three weeks later when they’re trying to figure out which bead has started weeping like it saw a ghost. Learned that from an old electrician who smoked filterless Pall Malls and claimed he once shocked a squirrel into Catholicism.
Anyway. Don’t trust roofs, and don’t trust smooth talking techies who say “heat maps confirm structural dryness.” Water laughs at heat maps. Water finds its way.
Wear gloves.
When you’ve finished painting something with Chalk Paint®, it’s important to think about how you’re going to protect your paintwork. After all, you don’t want all your hard work to go to waste! Sealing Chalk Paint® with Wax or Lacquer will not only protect your finish, but help the colour last longer. It means you can use your item without worrying about leaving behind marks or taking the paint off when you clean it.
https://www.anniesloan.com/us/techniques/how-to-seal-chalk-paint/
