Gable Roofs Form Triangle Ends
A gable roof has a center peak and sloping sides which form a triangle at each end. The peak is determined by the width of the roof and its pitch, or angle of slope. The peak is measured from the top of the end wall to the top of the point. Peak height can vary from almost nothing on a low-slope roof to 7 or 8 feet or more on a steep roof.
Peak Heights Vary by Locale
Roofs have higher peaks and steeper pitches in areas with heavy rainfall and lots of snow and ice accumulation. Those shed the load or weight more effectively. Milder climates and locales subject to strong winds, such as tropical storms, use shorter peaks and lower pitches to deflect the lateral load or force from wind.
Pitch and Run Determine Peak
The keys to calculating peak height are the run of the rafters, the distance from the peak to the wall, and the pitch, measured in inches of rise per foot. A 7/12 roof, for instance, rises 7 inches per foot of run. A 7-pitch roof with a 12-foot run will have a peak of 84 inches from the wall to the top. A 10-foot run would have a 70-inch peak, a 16-foot run, 112 inches.
Common Peaks Are 60 to 84 Inches
The most common pitches for houses are 5/12 and 6/12 and the most common runs are 12 or14 feet, for roofs 24 or 28 feet wide. A 12-foot run has a peak of 60 inches with a 5 pitch, 72 inches with a 6. A 14-foot run would have comparable peaks of 70 and 84 inches. A 14-foot run on a 6 pitch roof would have the same peak height as a 7-pitch on a 12-foot run.