Metal drip edges are used at rakes and eave edges of steep-slope roof assemblies as a means of properly terminating roof systems' edges. Requirements and guidelines for metal drip edge usage vary, and you should be aware of the differing information. Following is a brief review of metal drip edge requirements in the International Building Code,® 2018 Edition and International Residential Code,® 2018 Edition, as well as NRCA's recommendations.
In IBC 2018's Section 1507.2-Asphalt Shingles, specific requirements for metal drip edges are provided in Section 1507.2.8.3.
A drip edge is required to be provided at the eaves and rakes of asphalt shingle roof systems. A drip edge's flange should extend back onto the roof surface a minimum of 2 inches. Underlayment should be installed over a drip edge flange at eaves and under drip edge flanges at rakes. The vertical face of a drip edge should be a minimum of 1 1/2 inches and extend at least 1/4 of an inch below a roof deck's bottomside surface. Adjacent segments of drip edge shall be lapped a minimum of 2 inches. Drip edges shall be attached at a maximum 12 inches on-center fastening pattern.