Perry Gutter Replacement & Gutter Guard Installation

Gutter on a metal roof

Standing seam and corrugated metal roofs change the gutter calculation in a few specific ways. Water sheds off metal far faster than off asphalt, since there is almost no surface friction and nothing to slow it down. The practical effect is the same as increasing the pitch: a higher peak flow arriving in a shorter time, and a stronger tendency to overshoot the gutter entirely at the eave. That usually argues for larger gutter, more outlets, and careful attention to where the gutter sits relative to the roof edge. The second difference is snow. Metal sheds snow in slabs rather than gradually, and a released slab hitting a gutter will take it off the house. Snow retention devices on the roof are the standard answer and they are roofing work, but the gutter specification should assume they are either present or not. Third, dissimilar metals in contact can corrode, so the fasteners, hangers and the gutter material itself need to be compatible with the roof. Aluminum gutter under a steel roof is common and fine, provided the details are right. None of this makes the job unusual, but copying a specification written for shingles is a mistake.