Low Slope Roof Construction Details

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.

Low slope roof construction details.

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. Another approach is to build a cupola or ventilated doghouse in the middle of the low slope roof an approach championed by joe lstiburek. Roof assemblies with a pitch slope of less than 3 12 are considered low slope roofs. The roof assembly is defined as the roof deck along with the roof membrane and roof insulation.

These critical junctures account for the majority of roof leaks. Low slope roofs are often referred to as flat roofs. 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. Generic valley treatment details for metal panel roofs for low slope with and without substrates are included in the mbma metal roofing systems design manual chapter 12 metal roof details.

Problems at these points typically arise from improper application methods and the use of inappropriate or incompatible materials. 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. 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.