Curious if anyone’s actually had issues with synthetic underlayment breaking down over time?
I’m about 8 years in with synthetic underlayment (Midwest too), and so far, no problems. Had to pull a few shingles after a branch came down last year, and the underlayment looked basically new underneath. I do wonder how it’ll hold up after 15-20 years, but compared to the old felt I replaced, it’s night and day. Only thing I’d say is, if you get a leak, synthetic doesn’t absorb water like felt, so you’ll notice drips faster—could be good or bad depending on how quick you catch it.
Only thing I’d say is, if you get a leak, synthetic doesn’t absorb water like felt, so you’ll notice drips faster—could be good or bad depending on how quick you catch it.
That’s exactly what happened to my uncle’s place—tiny leak, but the drip showed up right away. Felt might’ve masked it longer, but then you’re dealing with rot. I’d rather know sooner, honestly.
- Synthetic underlayment does make leaks more obvious, but I’ve seen cases where folks miss the early signs anyway—especially if the attic’s not checked often.
- With felt, yeah, water can spread and hide for months. By the time you spot it, you might be looking at mold or rotted decking.
- I’m a bit skeptical about just adding a new layer over old shingles. Traps problems underneath, and you lose the chance to inspect the wood for damage.
- Full tear-off’s a pain (and pricier), but you get a clean slate. Less risk of hidden issues down the line.
- If you’re in a wet climate, I’d lean toward removing everything. Dry areas... maybe less urgent, but still worth considering.
I’m a bit skeptical about just adding a new layer over old shingles. Traps problems underneath, and you lose the chance to inspect the wood for damage.
Couldn’t agree more here. I’ve managed a few properties where folks tried to save money by layering, and it always came back to bite them—hidden rot, even carpenter ants one time. Full tear-off is a hassle, but you get peace of mind knowing what’s under there. Especially in humid areas, skipping that inspection step can mean way bigger headaches (and bills) later on. If you’re already seeing leaks or sagging, I’d say don’t risk it... strip it down and start fresh.
I get wanting to save a few bucks—believe me, I’ve been there. When we bought our place, the roof was already double-layered and I thought, “Hey, that’s one less thing to worry about.” Fast forward a couple years... surprise leak in the guest room, and turns out the decking underneath was half rotted. Ended up costing more to fix than if I’d just done a tear-off from the start. It’s a pain upfront, but you sleep better knowing what’s actually going on up there. Sometimes cheap now means expensive later.