Which holds up better over time: felt or synthetic underlayment?

That’s a good point about the budget - sometimes you just have to work with what you’ve got. I’ve seen felt hold up okay for a few years, but after a couple storms, it’s usually the first thing to go. Synthetic’s not perfect (that slipperiness is real), but I’ve had fewer callbacks for leaks when folks went that route. Still, if it’s just a shed or something temporary, felt can get the job done. Just depends how much hassle you want down the line.

I’ve seen both sides of this play out. On my own garage, I went with felt because it was cheap and I figured, “How bad could it be?” Well, after two years and one really nasty windstorm, I was up there patching leaks. That stuff just curled up at the edges and let water sneak in. Not a huge deal for a shed or something you don’t mind fixing every couple years, but I wouldn’t do it again for anything important.

Switched to synthetic on my neighbor’s roof last year - he’s got a low slope and lots of tree cover. The install was trickier (that slippery feeling is no joke), but it’s held up way better through rain and snow. He hasn’t had any leaks, even with all the debris piling up.

If you’re thinking long-term or want less maintenance, synthetic seems to win out. But if you’re just covering a chicken coop or something temporary, felt gets the job done for less money. Just depends how much you want to mess with repairs down the line...

I get where you’re coming from, but I’d push back a bit on the idea that synthetic always wins out for long-term durability. It’s true that synthetics resist curling and are less prone to water absorption, but not all synthetics are created equal. Some of the cheaper rolls can actually degrade under prolonged UV exposure if the shingles aren’t installed quickly - seen it happen on a couple jobs after delays. Felt, especially the heavier 30 lb stuff, can still hold its own in certain climates, particularly where you don’t get wild temperature swings or constant moisture.

One thing folks overlook is repairability. If you do get a puncture or tear, felt is usually easier to patch up without having to replace a whole section. Synthetics can be a pain if they rip, since adhesives don’t always stick well and you might end up with a bigger job than you bargained for.

I’d say it’s less about “synthetic vs felt” and more about matching the material to your climate, roof pitch, and how fast you’re getting the final roof on. There’s no one-size-fits-all answer...

That’s a really fair point about repairability - never thought about how much easier it is to patch felt. I’ve had a couple small leaks over the years and being able to just slap on a patch without tearing up a whole section definitely saved me some cash. Matching the material to your situation makes sense, especially if you’re watching the budget like I am.

I hear you on the budget thing - felt really does win points there, especially when patches are just a matter of cutting a chunk and slapping it on. I’ve patched more than a few spots myself (sometimes with less grace than I’d like to admit). Honestly, for folks who are handy and don’t mind a bit of DIY, felt’s forgiving nature is a big plus. Synthetics claim longer life, but they can be a pain when you have to fix even a small tear. Sometimes the classic stuff just makes more sense, especially if you’re not looking to re-roof every couple decades.