"Had a neighbor who skipped that step... ended up with condensation issues later on."
Yeah, condensation can sneak up on you, especially with metal roofs. When we replaced ours a few years back, I asked the roofer specifically about moisture barriers and he recommended a breathable underlayment. Glad I did, because another friend went with something cheaper and ended up with mold issues later. Did your neighbor have to redo the whole thing, or was it fixable without too much hassle?
Interesting points about breathable underlayment, but honestly, I've seen situations where even that wasn't enough. A few years back, I worked on a project where the homeowner had done everything "by the book"—breathable barriers, proper ventilation, the whole nine yards—and still ended up with condensation issues. Turns out, the real culprit was inadequate attic insulation and poor airflow inside the home itself.
Sometimes people overlook how interconnected these things are. You can have the best roofing materials and moisture barriers in place, but if your attic isn't properly insulated or ventilated, warm air from inside your home will still rise and meet that cold metal roof surface. That's when condensation forms. It's like leaving a cold drink out on a hot day—moisture just naturally collects.
If you're replacing an old leaky roof anyway, it's worth taking a step back and looking at your home's overall insulation and ventilation setup first. Check if your attic insulation is sufficient (usually R-38 or higher depending on your climate), and make sure you've got proper soffit vents paired with ridge vents or gable vents to keep air moving freely. I've found that addressing these interior factors first can sometimes reduce or even eliminate condensation issues altogether—even without investing heavily in premium underlayments.
Not saying breathable underlayments aren't helpful—they definitely have their place—but they're not always the silver bullet solution people think they are. It's more about looking at your home as a complete system rather than just focusing on one component at a time.
Good points about insulation and ventilation, but I'd argue that breathable underlayments can still make a noticeable difference—especially in humid climates. They're not a cure-all, sure, but pairing them with good airflow and insulation usually gives the best results from what I've seen.
Good call on breathable underlayments—I've seen them help quite a bit, especially in older homes where moisture buildup can be tricky. Have you noticed if the type or brand makes much difference? I've had mixed experiences myself; sometimes the pricier options didn't seem to justify the extra cost, but maybe that's just me. Also curious if you've found any particular ventilation setups that pair especially well with breathable membranes. I worked on a project last year where we combined ridge vents with breathable underlayment, and the homeowners said it noticeably improved their indoor humidity issues. Anyway, sounds like you're on the right track with your approach...roof replacements can be a headache, but getting these details right definitely pays off down the road.
"sometimes the pricier options didn't seem to justify the extra cost, but maybe that's just me."
I've had similar experiences with pricier breathable underlayments. Last year, I worked on a renovation project involving an older property with persistent moisture issues. We ended up trying a mid-range breathable membrane after debating between premium and budget options. Honestly, the results were pretty decent—no noticeable difference compared to the high-end stuff we'd used previously.
I'm curious about your ridge vent setup though... did you pair it with soffit vents or any other intake vents? We combined breathable membranes with ridge and soffit vents on another job, and homeowners mentioned a significant improvement in humidity control. Makes me wonder if the ventilation combo matters more than the membrane brand itself...
