It doesn’t always hit you the day after. Sometimes it’s two weeks later, you’re out there to yank a stubborn weed growing sideways under the gutter, and there’s this pucker in the roof coating. You scratch your head, then the coating. It flakes off like old biscuit crust. A few square inches today, next week it’ll be dinner-plate size.
Ash doesn’t just fall — it creeps, seeps, eats where it shouldn’t. After a wildfire, the metal roof takes a beating you don’t always see. Coated steel or galvalume, nice and prim before, now looks like it slept through a chemical nightmare. The paint doesn’t peel so much as surrender. Not all at once. Slow betrayal.
The Ash Itself — Not as Innocent as It Looks
Thing is, wildfire ash ain’t campfire ash. It’s not cozy-nostalgia-s’mores ash. It’s mineral-heavy, charred-chemical blender nonsense. It’s bits of car tires, melted aluminum siding, half a mattress spring. You leave that junk to marinate on a roof long enough — combined with water (fog, hose spray, whatever) — and you get a weak alkaline soup. Creeps right under the coating edge like gossip at a dinner party.
And if you think the clearcoat’s got your back? No, ma’am. It flakes faster than a fourth grader’s attention span. The adhesion layer between the paint and the metal just gives up. No ticker-tape parade, only dull white patches that get uglier in sunlight.
The ash from forest fires is relatively nontoxic and similar to ash that might be found in your fireplace. However, ash may contain unknown substances, including chemicals. In particular, ash and debris from burned structures may contain more toxic substances than forest fire ash, because of synthetic and other materials present in homes and buildings. Care should be taken when handling any materials from buildings that are either partially damaged by the fire (i.e., salvageable building materials remaining) or completely destroyed by the fire (i.e., only ash and debris remain). Fire ash may also irritate the skin, especially those with sensitive skin. If ash is inhaled, it can be irritating to the nose and throat and may cause coughing. Exposure to ash in the air can also trigger asthmatic attacks
https://www.cdhd.wa.gov/emergency/after-a-wildfire
Soap and Hope Ain’t Gonna Cut It
Saw one guy try to patch his delaminated panels with car wax and dish soap. Bless him. Roof looked like an oil slick in daylight. Still peeled like a bad sunburn after the first drizzle. So let’s not. First step’s ugly but there’s no shortcut: you gotta clean it down to bare sorrow. Strip the area — don’t dawdle. If your flakey spots are bigger than your hand, you’re looking at serious prep. Wire brush, angle grinder, maybe sandblasting if you’re aggressive or bored.
Don’t trust your eyes either. What looks like solid coating might be puckered underneath. Scrape until it fights back. Anywhere the edge crumbles, keep going. If it gives up too fast, it was never loyal.
When the Primer Becomes the Saviour
You ever meet someone who doesn’t say much but always shows up when it counts? That’s what primer is. Especially the good zinc-rich ones — they’re gritty, smell like trouble, and cling hard to metal. It’s gotta go over a bone-dry, scoured surface though. Moisture? Forget it. Trap just a whiff of water under primer and you’ll get bubbling like roadkill on a hot day.
Don’t skimp. One coat of decent primer’s worth more than two coats of paint pretending to be armor. Grey, rusty red, sometimes green — not for aesthetics, purely business.
Yes. A primer prepares the surface for the paint, it isn’t just an all over coat of paint. A primer is specially formulated to stick to the surface and dry with a surface finish that makes it easier for paint to stick to. If you don’t use a primer, you’ll need to apply thicker layers of paint for it to stick, and it will still be easier to rub off.
https://www.reddit.com/r/minipainting/comments/1bagtr3/is_primer_different_chemically_from_other_paint/?rdt=49231
Paint Ain’t Just Color. It’s Armor
This is where folks argue. “Should I just slap on another latex topcoat?” No. Breathe and walk away from the hardware aisle for a bit. Post-fire, the enemy isn’t UV (well, not only UV) — it’s *what’s still gassing off* from all that burnt mess. You want a paint system that’s chemically combative. Polyurethane or fluoropolymer if the budget isn’t crying. You’re not painting for pretty. You’re sealing wounds. High-solids formula. Apply like you’re frosting a spite cake. Thick, deliberate, angry strokes.
Don’t even bother if weather’s threatening rain in 24 hrs. Let it cure like it means it.
Cheap Brushes = Regret on a Stick
And here’s something no one says: don’t get cocky with rollers. They clump. They smear more than they spread. Get a mix of stiff brushes (for corners and overlaps) and decent shedless rollers, maybe. Think utility, not cosmetic perfection. Nobody’s sipping iced tea on that roof admiring the shine. It just has to Last. That’s the whole sermon.
Maintenance After the Mess
Once repainted, don’t trust it yet. Ash particles keep hanging around like bad exes. Sneak onto the roof every few months. If you see little bubble-pimples, or hairline splits in the new coat — jump on it. That’s your red flag. Re-clean. Spot-prime. Touch-up. It’ll never love you like a new roof, but it won’t betray you in the rain either.
And for pete’s sake, don’t let leaves build up around your roof valleys again. Wet vegetation’s like inviting trouble to stay for dinner and do your taxes.
Final Thoughts? Well… Sorta
Roofs don’t complain. They just fail quietly. Especially coated metal ones. The delamination after ashfall doesn’t always show up with a bang — sometimes it just sulks there, under the radar. But once you’ve danced the patch-and-paint shuffle — and you will if you’re lucky enough not to need full panel replacement — you start to understand roofs a little better.
They’re like grumpy old relatives. If you ignore them, they’ll remind you who’s boss. Catch the small stuff while it’s still small, even if it feels silly crawling up there with a flashlight at 7am on a Tuesday before work.
And yeah, it doesn’t look graceful or clever or Instagram-worthy. But roofs aren’t Instagram. They’re hard hats for our houses.
Don’t leave yours cracked.
