FACT
Some buildings are built with outside corners that are either greater than or less than 90 degrees. When this occurs on hip roofs, it can require special hip treatments.
ANALYSIS
When this occurs with vertically seamed metal roofs, the standard hip treatment will usually work. However, with shake, tile, slate, and shingle facsimile products that normally utilize individual “one-per-course” Hip Caps, special attention may be necessary. Whether or not special attention is necessary depends upon the exact angle of the corner as well as upon the pitch of the roof. Contact the roofing manufacturer who should be able to assist in determining the best solution. However, there are four common solutions and determining the best one might require trial and error.
One solution is to use the standard Hip Caps that accompany the roof system. If, however, they do not lock over or line up properly with the shingle courses, alternatives must be explored. One alternative is to use Ridge Caps on the hip line. See Technical Bulletin #19 for details on how this is accomplished. Another method is to use Mansard Caps that are also installed “one-per-course” but are less angled on their bottom edge. The fourth method is to use a lineal “inverted-valley” style of hip closure. Again, trial and error with these different approaches may be required in order to determine what will work best with each particular roof pitch and corner angle combination.
