The shingles on my 17-year-old roof are worn and need to be replaced. I discovered while repairing shingles after a storm that there is no felt on my roof: the shingles are nailed directly to the plywood roof, and slight gaps exist between plywood sheets. My question: Which is best? New shingles installed on top of old shingles? Or, remove shingles, add felt, and add new shingles? Thanks for all responses.
i would remove the old shingles if they are curling or extremely worn. if they are laying pretty flat you may can go over them, but i would use two layers of 30# felt.(make sure your felt and shingle nails are long enough to penetrate the deck)Also, make sure you have a contractor look at your roof to be sure it can withstand the weight. the average square if shingles is going to weigh 200-250 lbs! hope that helps!
