The first step is to make a scale drawing of the entire roof, locating the exterior walls, ridges, and all rafters, as in Figure 1A. The perspective sketch (right) shows the location of the unequal hip rafter.Ī note before you start: You’ll get the most out of this article if you read it with framing square and a scrap of plywood nearby, so you can perform some of the layout calculations.
This is useful for material takeoffs and as a job-site reference. The author begins any complex roof project by making a scale framing plan of the roof (left).
For the purposes of this article, I’ll show how to frame the intersection of two hip roofs of unequal pitch. Master it, and you can handle any of the numerous situations where two roofs of unequal pitches meet, whether at a hip or a valley. The direct correlation between drawings and cuts makes this method accurate and reliable. The key to the Zepp method lies not in fancy math, but in using the framing square to make scale drawings of the crucial angles and cuts, then transferring the measurements from sketch to lumber.
Don Zepp taught advanced roof framing while I was a student at Williamson Trade School, in Media, Pa., and I feel that his method is the easiest to understand and use in the field. Or you can use the Zepp method, which requires nothing more than a framing square and a pencil. Another is to buy a fancy framing calculator and take a course in trigonometry. One approach is to order twice the framing lumber required and keep cutting hips and valleys until you get it right. Then it happens: That bid you submitted for the job with the adjoining, unequally pitched roofs gets accepted, and you’ve got to figure out a way to frame it. After struggling with hip rafters and talking to an old-timer or two, novice framers discover that joining two roofs isn’t that tough - for hips and valleys you just cut all your bevels at 45 degrees, and use 17 instead of 12 for the run on the framing square.