I’ve seen overlays work out okay, but man, you really have to trust the bones underneath. My uncle tried to save a few bucks on his old ranch house—just slapped new shingles over the old ones. Looked fine for a couple years, then a squirrel found a soft spot and basically moved in. If you’re not 100% sure about the decking, it’s like rolling dice. I do agree about the ventilation though... without it, even the best shingles are gonna cook.
I get wanting to save money, but after what I went through, I’d never just add a new layer. My place is only 15 years old, but when we moved in, there were two layers of shingles and some spots felt “spongy” when you walked on the roof. Ended up having to rip everything off anyway because the decking was rotted in places. Cost more in the long run. If you can swing it, full tear-off just gives peace of mind.
- Totally agree about the peace of mind with a full tear-off.
- When we did a layover on a job last month, we found out after that the old shingles were hiding some soft decking—couldn’t tell until it sagged more.
- Two layers can trap heat and moisture, which just speeds up rot.
- Layovers seem cheaper up front, but if the base is bad, you’re just covering up problems.
- Only exception I’ve seen is when the first layer’s still in great shape and the roof’s not that old... but that’s rare.
- Full tear-off’s more work, but you know exactly what you’re dealing with underneath.
That’s a good point about heat and moisture getting trapped—especially in humid climates. Has anyone here tried a tear-off and then gone with a lighter-colored or reflective shingle? Wondering if that helped with attic temps or energy bills over time.
I actually went the other way—kept the old layer and just added new shingles on top, mostly because I was worried about cost and mess. I live in the southeast where it’s muggy most of the year, and honestly, I didn’t notice a huge difference in attic temps after the new layer went on. Maybe a slight bump, but nothing drastic. I’ve heard lighter shingles can help, but I think attic ventilation and insulation made more of a dent for us than the color did. Just my two cents... sometimes the shingle color gets overhyped.