Drip edge is the flashing that goes around the outside edge of your roof between the roof decking and the roofing felt. Properly installed drip edge will prolong the life of your fascia and roof decking. By directing water away from the fascia and forming a protective seal for your decking, it prevents the moisture that promotes wood rot from collecting along the edge of your roof. Installation is simple and requires few tools.
Begin at one corner of the lower edge of the roof. Set up your ladder so that you can safely and comfortably reach the edge of the roof. Drip edge flashing is formed into a slightly lopsided "T" shape. The longer portion of this "T" is placed flat against the roof with the finished edges of the flashing facing out.
Place a section of drip edge on the bare roof sheathing with the end of the drip edge even with the outer edge of the sheathing. Leave a 1/4-inch gap between the lower portion of the drip edge and the fascia or roof sheathing.
Nail the drip edge in place. Use one roofing nail every 12 to 18 inches. Drive the nails through the upper edge of the flashing about 1/2 inch from the edge.
Place the second strip of drip edge on the edge of the roof in the same fashion as the first. Overlap each new section by at least 6 inches over the previously installed section.
Install roofing felt after all lower roof edges are complete.
Begin at the lower edge on one corner of your gable to install side (gable) drip edge flashing. Place the drip edge on top of the roofing felt with one end even with the corner of the roof.
Fasten the drip edge to the roof the same way you did for the lower roof edges. When you reach the peak of the roof, use your tin snips to make a single cut in the lower portion of the drip edge even with the peak. This will allow you to fold the upper portion of the drip edge smoothly over the top of the roof and continue down the other side of the roof. Do not join two pieces of drip edge at the roof's peak.
The National Association of Home Builders (NAHB) recommends installing drip edge underneath roofing felt on lower roof edges and on top of roofing felt for gables. For gambrel or barn-style roofs, make a single cut on the bottom of the drip edge to make a smooth fold at each peak. Continuous runs of drip edge provide better protection than shorter pieced-together sections.