What are drip edge and kick-out flashing, and does my house need them?

Drip edge: the roof's lip

Water running off a roof does not fall straight down. Surface tension pulls it around the edge of the shingle and back toward the fascia, where it runs down the face of the board or, worse, behind the gutter. Drip edge is an L-shaped metal strip installed under the roofing at the eaves and rakes. Its lower leg hangs past the fascia and has a small hem that breaks the water's grip, so it drops into the gutter or clear of the wood.

On a house without it, the fascia behind the gutter stays wet after every rain, the paint fails along the top edge, and the board rots from the back where you cannot see it. We find missing or buried drip edge on a large share of the fascia repairs we do.

Kick-out flashing: the corner that soaks walls

Wherever a sloped roof edge dies into a vertical wall, such as a garage roof meeting the two-story part of a house, or a porch roof running into a side wall, the step flashing along that joint carries water down to the bottom. At the bottom, the water has to get into the gutter. Without a kick-out, it runs off the last piece of step flashing straight down the wall behind the gutter end.

Kick-out flashing is a small, bent piece at that last step that angles outward and diverts the stream into the gutter. It is one of the smallest pieces of metal on a house and one of the most consequential. The telltale of a missing one is a dark vertical streak on the stucco below the corner, often with soft trim, a rotted window frame or a damp spot inside the wall beneath it.

Does your house have them?

Stand at the corner of the house and look at the roof edge. Drip edge shows as a thin metal lip just under the first course of roofing, usually painted or factory finished, hanging slightly past the fascia. If the shingles simply end at the fascia, or the gutter hides the edge entirely and the fascia behind it is stained, assume it is missing.

For kick-outs, walk to every spot where a roof edge meets a wall and look at the bottom of that joint. A little angled metal tab that pokes into the gutter is the kick-out. A streak on the wall below is the absence of one.

• Stained or peeling fascia behind the gutter: suspect missing drip edge
• Dark streak on stucco below a roof-to-wall corner: suspect missing kick-out
• Soft trim or a damp interior wall below that corner: water is already in

What the codes say

The residential code adopted in California, which is based on the International Residential Code, requires drip edge at eaves and rakes on asphalt shingle roofs and requires flashing where roofs meet walls, including kick-out flashing at the base of those intersections. Older houses were built under earlier codes, and many were reroofed without anyone adding what the new code calls for.

A reroof is the natural time to add both. If your roofer does not mention drip edge and kick-outs, ask. It is a small line item and it protects the wood below for the life of the roof.

Adding them to an existing roof

Drip edge can sometimes be slipped under the first course of shingles on an existing roof, though it is cleaner at reroof time. A kick-out can be retrofitted by lifting the bottom shingles and step flashing at the corner, cutting back a little stucco, and setting the kick-out so it laps correctly with the step flashing above and the building paper behind. That is roofing and stucco work, so it is coordinated with a roofer.

What we handle is what the missing metal did: the rotted fascia, the trim at the corner, the window sill below the streak. Repairing that wood without adding the flashing means doing it again, so the two go together.

Related questions

Sources and further reading