What size and style of drip edge should I use?
Short answer. Use a T-style drip edge or a gutter apron at the eaves when you have gutters, so water lands inside the gutter, and a standard L or T profile on the rakes. Move to a longer leg when the fascia sits low or the deck edge is thick, and choose heavier metal where the house is exposed to strong wind.
Match the profile to the edge
- Eaves with gutters. A T-style profile whose kick sits over the gutter, or a gutter apron with a longer leg that reaches into it. The goal is no path for water between the gutter's back and the fascia.
- Eaves without gutters. A T-style profile with a strong outward kick so water drips well clear of the fascia and siding below.
- Rakes. An L or T profile, color matched. Underlayment runs under the drip edge at rakes so wind-driven rain cannot get behind it.
- Thick or built-up edges. An extended profile with a 2 1/2 inch or longer face.
- Low-slope sections. A wider roof flange gives more lap under eave membrane where water moves slowly.
Metal and thickness
Aluminum is common and rustproof. Galvanized steel is stiffer. On a long, straight eave or an exposed hilltop lot, heavier stock stays straighter and resists uplift better. Keep copper with copper.
Fastening in wind
The code maximum is 12 inches between fasteners. In exposed locations, closer spacing helps keep the edge, and the shingles sealed to it, from peeling back. Wind usually attacks a roof at its edges and corners first.
Color
Match the gutters for a clean line at the eaves, or the fascia if gutters are a contrasting color.
See more in drip edge explained, gutter sizing and seamless gutters, and wind damage to roofs in Georgia.