Standard metal drip edge is the most common type of drip edge installed on shingled roofs. Used primarily on residential homes, this kind of drip edge is made at a 90-degree angle with a lip extending out from the corner. The drip edge allows water from the roof to run directly into the gutter system. A longer edge is nailed down under the shingles and lips over the corner of the roof and onto the fascia board before the gutters are installed.
No lip 90-degree metal drip edge is available for rolled roofing. These types of roofs are designed for large commercial buildings that have no gutters. The water runs off the roof through a drainage system designed into the building. The 90-degree drip edge has no extending metal protruding out from the corner of the metal. The edge nails onto the edge of the roof, before the rolled roofing is installed. The roofing material is rolled out over top of the drip edge to prevent the roof from leaking.
Vented metal drip edge is available for buildings that lack soffit or overhangs. Ventilating the roof needs to prevent the buildup of moisture under the roofing material is necessary to prevent premature damage. Condensation causes the wood to dry rot if not properly ventilated. The drip edge looks similar to the standard drip edge, but has small air vents cut into the lip of the material. Along the underside of the lip of the metal, vents allow air to reach the inside of the roof, preventing condensation.
Metal drip edge that prevents water from running off the roof and flow away from the sides of the building is called slag stop drip edge. Instead of a lip protruding out from the edge of the roof, the lip is raised above the roof-line or roof edge. Primarily used on hot tar roofs where the water is distributed into a drainage system in the corners of the building, this type of metal drip edge is attached completely around the roofs edge.