What does a roof flashing types chart show, and where does each type go?
Short answer. A roof flashing chart pairs each flashing type with the joint it protects: drip edge at the eaves and rakes, step and counterflashing where a roof meets a wall or chimney, apron flashing at a headwall, kickouts at the bottom of a roof to wall joint, valley metal where two slopes meet, and boots or jacks around pipes. Most roof leaks start at one of these joints, not in the open field of shingles.
The chart, type by type
- Drip edge. Where: eaves and rakes. Job: carries water past the fascia into the gutter and keeps it off the decking edge. Usual metal: aluminum or galvanized steel.
- Step flashing. Where: sloped sidewalls of dormers, chimneys and two-story walls. Job: one L-shaped piece per shingle course sheds water back onto the roof. Usual metal: aluminum, galvanized or copper.
- Counterflashing. Where: masonry such as chimneys and brick walls. Job: covers the top of the step or apron flashing; set into a mortar joint. Usual metal: coated aluminum, painted steel, copper or lead.
- Apron or headwall flashing. Where: where a slope dies into a vertical wall, and the downhill face of a chimney. Job: one continuous piece lapped over the shingles below.
- Kickout flashing. Where: the bottom of a roof to wall joint at the eave. Job: turns water into the gutter instead of down the wall.
- Valley flashing. Where: the inside corner where two slopes meet. Job: carries the heaviest water flow on the roof; exposed metal valleys must be at least 24 inches wide under the code, usually over an ice and water membrane.
- Pipe boots or jacks. Where: plumbing vents. Job: base lapped into the shingles, collar sealed to the pipe.
- Vent and flue flashing. Where: exhaust hoods, box vents and metal flues, which also get a storm collar.
- Cricket or saddle. Where: the uphill side of a chimney or curb wider than 30 inches. Job: splits water around it so it cannot pond.
- Skylight flashing kits. Where: around the unit. Job: head, step and sill pieces sized to that skylight.
Using the chart to chase a leak
Find the stain, then look uphill on the roof for the nearest joint on this list. Water often travels along a rafter before dripping, so the entry point can be several feet above the stain. See roof flashing explained and drip edge explained.