"insurance companies always find some reason to bump premiums."
Yeah, that's been my experience too. But beyond insurance, have you looked into the actual fire resistance ratings between EPDM and TPO? When I was researching for my own roof replacement, I noticed TPO often comes with built-in fire retardants, while EPDM sometimes requires additional treatments or coatings. Wonder if anyone here has firsthand experience with how these differences actually play out in real-world scenarios...
When I was looking into this a couple years back, I found the same thing about TPO having built-in fire retardants. EPDM can definitely meet fire codes too, but it usually needs extra coatings or ballast to get there. From what I remember, EPDM is naturally more flammable because it's rubber-based, whereas TPO is thermoplastic and designed with flame resistance in mind from the start.
I haven't personally seen either material tested by an actual fire (thankfully!), but a friend of mine who manages commercial properties had an incident at one of his buildings. It wasn't a full-blown fire—more like sparks from nearby welding work landing on the roof. He said the TPO held up surprisingly well; it melted slightly but didn't ignite or spread flames. They patched it up pretty easily afterward. He mentioned that if it'd been EPDM without proper coatings or ballast, things might've gotten messier.
Still, I wouldn't completely rule out EPDM just based on fire resistance alone. It's got some advantages in durability and ease of repair that might outweigh the extra hassle of adding fire-resistant treatments. Plus, depending on your local building codes and insurance requirements (yeah, those again...), you might not even have much choice anyway.
One thing I'd suggest is checking with your local fire marshal or building inspector—they usually have good insights into how these materials perform locally and what they prefer to see installed. Sometimes their recommendations can even help smooth things over with insurance companies...though let's be honest, they'll probably find another reason to bump premiums anyway!
That's an interesting perspective, especially the anecdote about the welding sparks. It's good to have real-world examples like that, since data sheets and marketing materials can only tell you so much. I've been researching this myself lately for a smaller-scale project, and I agree that EPDM shouldn't be dismissed outright. While TPO seems to have the edge on fire resistance out-of-the-box, EPDM's durability and ease of patching appeal to me as a DIYer—especially if you're not expecting regular fire hazards.
I do wonder though... how much extra hassle (and cost) those additional coatings or ballast layers add to an EPDM install? If it's just minor, maybe it's worth it for the other benefits EPDM offers. Might be something I'll ask the inspector about next time they're around. Good tip on checking with local officials too; sometimes their preferences aren't exactly what you'd assume from reading forums or manufacturer specs.
Good points raised here, especially about the hidden costs of EPDM add-ons. From my experience, ballast layers aren't too complicated to install, but they do add weight—so you'll need to confirm your roof structure can handle it. Coatings, though... those can get pricey and sometimes finicky to apply evenly. Still, if fire risk isn't a daily concern, EPDM's ease of repair might outweigh these hassles. Definitely smart to double-check with local inspectors; they often have insights you'd never guess from product brochures alone.
Hadn't really thought about the weight issue until you mentioned it. When we redid our garage roof, the inspector pointed out the same thing—ballast isn't rocket science, but older structures might struggle. Definitely worth checking before you commit to EPDM.
