Inspected a home today – 12 years old. About 3’ sq. patch of asphalt shingles was missing. No underlayment was visible. Picked up the shingles at the edge and no underlayment was visible.
A veteran general contractor on the jobsite said it was not required then or now, saying “think about it, the underlayment is full of holes too”. Guess he’s got a point there. He said even today, when a roofer gives him a price on a roof installation, the price differs depending on whether underlayment is included.
I believe underlayment is required in IRC R905.3.3. How long has it been required? Thanks.