A.Architect and roofing consultant Harrison McCampbell responds: Most shingle manufacturers, along with the Asphalt Roofing Manufacturers Association’s Residential Asphalt Roofing Manual, call for a 1/4-inch to 3/4-inch overhang at both rakes and eaves. In my opinion, the felt underlayment should also extend beyond the drip-edge (by 1/4 to 1/2 inch). Don’t overdo the overhang — shingles that extend more than 3/4 inch can eventually bend and fracture, leaving the roof sheathing and fascia vulnerable to water damage.

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