Low Slope Roof Construction Details

Low slope structural roofing generally used on roof pitches ranging from 12 to 3 12 consists of interlocking panels commonly called standing seam roofing that run vertically along the roof surface.

Low slope roof construction details.

Regular asphalt shingles and standard skylights will work at pitches of 4 12 or greater but at lower pitches you have to use different materials. The roof assembly is defined as the roof deck along with the roof membrane and roof insulation. Low slope roofs are often referred to as flat roofs. By low slope roofing we mean any roof that is pitched at less than 4 inches of rise in 12 inches of run or 4 12 pitch.

These panels generally come with a painted mill finish or a clear acrylic finish. These critical junctures account for the majority of roof leaks. Problems at these points typically arise from improper application methods and the use of inappropriate or incompatible materials. That includes soldered metal roofing or synthetic membranes.

Roof penetrations should be kept to a minimum and should be located within the flat of the panel where possible as opposed to near seams. If the upper edge of a low slope shed roof intersects a vertical wall the most logical approach in my opinion is to detail the roof as an unvented roof. The most critical application points on low slope roof systems are at flashings penetrations and accessories. Another approach is to build a cupola or ventilated doghouse in the middle of the low slope roof an approach championed by joe lstiburek.