Need advice on replacing an old leaky roof

NEED ADVICE ON REPLACING AN OLD LEAKY ROOF

I get where you’re coming from about the rain noise - metal roofs can sound like a drumline during a downpour. But honestly, I’ve always thought people go a little overboard with all the extra layers. I mean, mineral wool is great for sound, sure, but it’s not exactly the most eco-friendly option out there, especially if you’re trying to keep your carbon footprint low. I went with dense-pack cellulose between the rafters on my place, and it’s been solid for both noise and insulation. Plus, it’s recycled material, so it felt like the right call.

About underlayment, I actually prefer old-school felt over synthetics, even though everyone seems to be pushing synthetics these days. Maybe it’s just nostalgia, but I’ve seen felt hold up just fine, especially if you’re not in a super humid climate. Synthetics might last longer on paper, but I’ve had a couple tear during install, which was a pain. Felt’s just more forgiving if you ask me.

Skylights and vents, though... those are always a headache. I’ve found that no matter how careful you are, leaks love to find their way in. I tried those fancy flashing kits once, but honestly, just taking the time to do proper step flashing with a good bead of high-quality sealant has worked better for me than any “system” out there. One thing I will say - don’t skimp on the ice and water shield around those openings. I learned that the hard way after a wind-driven rainstorm found a weak spot around my bathroom vent. Had to rip out half the ceiling to fix it. Not fun.

Guess what I’m saying is, sometimes the tried-and-true methods beat the latest products, especially if you’re willing to put in the extra elbow grease. And if you’re thinking green, there are definitely better options than mineral wool for sound and insulation. Just my two cents.

NEED ADVICE ON REPLACING AN OLD LEAKY ROOF

You’re not wrong about skylights and vents being a pain - those spots are just magnets for leaks if you’re not careful. I’ve had my share of trouble with “premium” flashing kits too, and honestly, nothing beats slow, careful step flashing and a steady hand with the sealant. Felt underlayment’s a classic for a reason, but I’ll admit I’ve started using synthetics in wetter climates just for the extra peace of mind. Dense-pack cellulose is a solid call if you’re thinking green - mineral wool’s not my first pick either. Sounds like you’re making smart choices all around.

NEED ADVICE ON REPLACING AN OLD LEAKY ROOF

- 100% agree on skylights and vents being the weak spots. I’ve seen more callbacks on those than anything else, especially when someone tries to rush the install or skips a step with the flashing.
- Step flashing is the only way I trust, honestly. Those “all-in-one” kits look good on paper but in practice, they just don’t hold up over time. I’ve had to rip out more than a few and redo them the old-fashioned way.
- Felt underlayment’s fine for most jobs, but if you’re in a spot that gets hammered by rain or snow, synthetics are worth the extra cost. They lay flatter, don’t wrinkle as much, and you get a better seal around fasteners. Only downside is they can get slippery if you’re up there on a hot day - watch your step.
- On insulation, dense-pack cellulose is solid, but I’d still lean toward spray foam if you can swing it budget-wise. It’s pricier up front, but you get better air sealing and fewer headaches with moisture down the line. Mineral wool’s okay for soundproofing, but I’ve never been impressed with it for roofs.
- One thing I’d add: check your roof deck before you start. If there’s any rot or soft spots, replace those sections now. Nothing worse than putting on a new roof and finding out six months later you’ve got sagging or leaks because the deck was shot.
- Last thing - don’t cheap out on the ice and water shield, especially along the eaves and valleys. That’s where most leaks start, and a little extra coverage there saves a lot of hassle.

I’ve seen folks try to cut corners to save a few bucks, but it always comes back to bite them. Take your time, use the right materials, and you’ll only have to do this once... at least for a couple decades.

NEED ADVICE ON REPLACING AN OLD LEAKY ROOF

- Right there with you on skylights and vents - those are always the first spots I check when someone calls about a leak. Even with good flashing, I’ve seen water sneak in if the install’s rushed or the sealant’s not right.
- Step flashing over “one-piece” kits every time. The kits look slick, but after a few freeze-thaw cycles, they just don’t hold up. I’ve had to explain that to more than one homeowner who thought they were getting an upgrade.
- Synthetics for underlayment are a game changer, especially in humid climates. Only thing I’d add is to double-check the manufacturer’s warranty - some brands have weird exclusions if you use certain fasteners or overlap patterns.
- On insulation, spray foam’s great for air sealing but watch out for ventilation issues. I’ve seen a couple roofs where folks went all-in on closed-cell and ended up with trapped moisture because they didn’t vent the roof deck properly.
- Decking - yep, can’t stress that enough. If it feels spongy underfoot, just replace it now. Had a job last year where we found carpenter ants in the sheathing... not fun.
- Ice and water shield: more is better, especially if you’re anywhere near trees or north-facing slopes.

Cutting corners never pays off with roofs. It’s one of those things where you really do get what you pay for...

Good point on spray foam and trapped moisture. I’d add one item to the estimate: ask every contractor to spell out the ventilation plan in writing, not just the insulation and underlayment specifications.

Step by step, the proposal should identify:

1. Where intake ventilation will come from - soffit vents, over-fascia vents, or another approved method.
2. Where exhaust ventilation will exit - ridge vents, gable vents, or roof vents.
3. How the contractor will maintain a continuous air channel above the insulation from the eaves to the exhaust.
4. How they’ll handle interruptions such as skylights, valleys, chimneys, and cathedral ceilings.
5. Whether the existing vents will be removed, retained, or supplemented, and how the final airflow will be balanced.

I wouldn’t assume that synthetic underlayment, ice-and-water membrane, or spray foam solves moisture problems by itself. Those products address different risks; ventilation still needs a coherent design, and local code and the roof manufacturer’s requirements should govern the details. A written plan also makes it much easier to compare bids and catch a proposal that simply says “ventilate as needed.”