09-20-2015, 10:25 PM
Overlay is entirely viable in your state, but it tends to shorten the lifespan of the roof. The extra weight isn't really an issue, but the ability to shed heat is. You end up cooking the shingles out of both sides. Can also cause the sheathing to delaminate if it is ply or OSB.
If you are going with comp 3-tab over more comp 3-tab, you might be looking at about 10-15 years out of the overlay before it should probably be replaced. Some parts of KY might let you go up to three layers, though I wouldn't recommend it. That's a lot of added material with very little holding power. You end up with a nail that doesn't have a lot of bite on the sheathing. The guys that do overlays correctly also know to dial the pressure back on their guns, otherwise it is very easy to deep-set a nail right through the overlay shingle.
It will most likely take the roofers less than an hour to strip it. They will probably just run a roof rake down the slope and into their dumpster or trailer if they can park it close to your eaves.
If anyone recommends staples on an overlay instead of nails, call them your choice of obscenities and slam the door on their face.
If you are going with comp 3-tab over more comp 3-tab, you might be looking at about 10-15 years out of the overlay before it should probably be replaced. Some parts of KY might let you go up to three layers, though I wouldn't recommend it. That's a lot of added material with very little holding power. You end up with a nail that doesn't have a lot of bite on the sheathing. The guys that do overlays correctly also know to dial the pressure back on their guns, otherwise it is very easy to deep-set a nail right through the overlay shingle.
It will most likely take the roofers less than an hour to strip it. They will probably just run a roof rake down the slope and into their dumpster or trailer if they can park it close to your eaves.
If anyone recommends staples on an overlay instead of nails, call them your choice of obscenities and slam the door on their face.
Math is tough. Let's go shopping!