Do I need flashing on my roof?
Where flashing is required
The International Residential Code, which Georgia uses with state amendments, requires flashing at wall and roof intersections, wherever the roof changes slope or direction, and around roof openings, and metal flashing must be at least as thick as 26 gauge galvanized steel or an equivalent corrosion resistant metal. It also calls for drip edge at the eaves and rakes of shingle roofs, and a diverter, usually called kickout flashing, where a roof edge dies into a sidewall.
- Step flashing along sidewalls and the sides of chimneys and dormers.
- Counterflashing over the step flashing on brick or stone.
- Apron or headwall flashing where the top of a roof meets a wall.
- Valley lining where two slopes meet.
- Pipe boots and vent flashing around every penetration.
- Drip edge on the eaves and rakes.
What happens without it
Water runs down a roof in sheets and concentrates at every joint. Without flashing, it soaks into the wall sheathing behind siding, rots the decking along a chimney, or wicks under the first course at the eave and into the fascia. These leaks often stay hidden for years because they run inside walls instead of dripping onto a ceiling.
Why caulk is not a substitute
Sealant and roofing cement crack as the sun and Georgia heat move the roof every day. Flashing works by layering, each piece lapped so water always flows onto the next piece down, and that keeps working long after any sealant fails. Sealant is a helper at a few spots, never the main defense.