Some roofs are constructed with flared gables. In most cases, this is done with the ridge wider than the eave though, in rare instances, it can be the other way around.
Flared gables are a common feature on chalet and rustic homes that might often be subject to heavy snowloads. When the ridge is wider than the eave, everything that runs down the roof above the flared area will end up running into or off of the gable. If the gable flashing traps this water and debris, problems will eventually occur. Another consideration with flared gables occurs with horizontally-run metal roofing systems and is that, due to the angle that is created when the ends of the courses are cut, any standard “single course” gable caps will no longer work because they will not be long enough. This is the case no matter whether the ridge or the eave is the wider part.
The only solution to flared gables when the ridge is wider than the eave is a flashing method that allows water and debris running down the roof to fall safely off of the flared gable and not be trapped in any sort of water channel. This is often accomplished by bending the panels (either horizontal or vertical panels) over the gable and into a channel that has its outer part lower than the roof deck. (This is important so that the channel doesn’t flood back onto the roofdeck.) Flared gables can also be handled by bending the metal panels back on themselves and locking them into a trim piece actually on top of the roof deck rather than down the fascia.. Overall, this installation is similar to installing panels into an Open Valley system — see Classic Products’ Technical Bulletin #10. This sort of flashing is also used when the eave is wider than the ridge if the only other flashing method involves individual caps for each course of shingles.
Classic Products, Inc.