Drip edge is the aluminum flange that folds underneath the bottom layer of asphalt shingles and covers the front portion of the fascia. The aluminum fascia is then slid underneath the drip edge to create a watertight seal and protect one of the most delicate parts of a roof.
The roof must be striped down to its basic underlayment before you install drip edge. Whether you’re starting from scratch, or you’re remodeling, the roof must be ready with an organic felt paper underlayment. If you’re using Zip System Sheathing then an underlayment isn’t required. Check out how to use tar paper to dry in a roof for more details on this part of the roofing process.
With all of the nails pounded down and the felt paper/tar paper in place you can begin bringing materials to the roof. Tin snips, roofing nails, tar/bull/butyl and the drip edge should all be set on the roof for easy access.
You may want to attach a ledger board for safety if your roof is steep. Just make sure that the ledger board is set back enough so that it doesn’t get in the way of the drip edge. Also attach a 2×4 block to the front of the sub fascia below the drip edge line where your ladder rests against the roof. This will prevent your ladder from getting in the way and from denting the drip edge when you climb up and down.
Drip edge is fairly straightforward to install, but there are a few basics you should know before beginning. Overlapping each piece by at least 2″ is code in most areas, especially high wind regions. This can be a little difficult without first crimping the male end flat and nipping a 45 degree angle on each ear of the male end.
Nailing patterns for drip edge consist of about every 24″ but can vary from area to area. In higher wind zones, 16″ is a common distance for nails. Attach a nail on each end a minimum of 4″. Set nails back towards the top of the drip edge, trying to penetrate the sub fascia below when possible. Keep in mind, the more you nail the drip edge in tight patterns, the more likely the chance you will get oil canning. Oil can is when metal tries to expand and contract when sunlight hits it, but it cannot because of the tight nailing pattern.
Starting from the least conspicuous area on the bottom corner of the roof, cut and bend the drip edge to travel up the rake of the roof and across the front, with the smaller end traveling up the rake. At least 24″ should travel up the rake. Start you laps in the most inconspicuous place possible. In other words, keep your laps away from the most traveled areas so you don’t see them.
Work your way from bottom to top with the last pieces being the top piece on the ridge of the roof. This is the cap piece. Once you’ve got all of the drip edge on the roof, you can tar or butyl tape the seam to prevent future water problems. Many people skip this step, but I find the extra time spent is well worth the added protection from future leaks.