What edge trims does a metal roof need?
Short answer. A metal roof needs trim wherever panels end or change direction: eave trim at the bottom edges, rake or gable trim along the sloped edges, ridge and hip caps at the peaks, valley flashing where planes meet, sidewall and endwall flashings against walls, and transition trim at pitch changes. Each piece sheds water past a joint the panels cannot seal on their own, so trim work decides how watertight the roof is.
The trim list
- Eave trim: bottom edge; carries water into the gutter.
- Rake or gable trim: sloped edges; covers the cut panel edge and fascia and resists wind uplift.
- Ridge cap: covers the peak where two planes meet; vented versions allow attic exhaust.
- Hip cap: covers the sloped peaks on hip roofs.
- Valley flashing: a wide pan in the inside corner where two planes meet, carrying heavy water flow.
- Sidewall flashing: where a roof slope runs alongside a wall.
- Endwall flashing: where the top of a slope dies into a wall.
- Transition trim: at a change in pitch, such as a porch roof flattening out.
- High-side or peak trim: at the top of a shed roof.
Supporting parts
Trims rely on foam closures to seal panel profiles, butyl tape and sealant at laps, and matching fasteners. Wall flashings usually need counterflashing so water cannot get behind them.
How trims fail
- Laps installed against the flow of water.
- Missing closures or sealant.
- Trims fastened too far apart, especially rakes in wind.
- Field-bent trim that does not match the panel profile.
Buying and matching
Order trims from the same manufacturer and paint system as the panels so colors match and profiles fit. Trims come in fixed lengths and overlap at joints, with each lap running downhill.