![]() Keeping all of the crowns pointing up prevents waves from marring the finished roof.įor more photos and details on framing a roof valley, click the View PDF button below. Because most framing lumber is not perfectly straight, I check each piece and mark the crown before I start cutting the lumber into rafters. The valley rafter is marked for a 12-in-17 pitch and then cut with a double bevel to fit into the ridge intersection. On the common rafters, the plumb cut is marked with a framing square for a 12-in-12 pitch (45°) and cut square (i.e., no bevel). The first cut that I make on both the common rafters and the valley rafter is the plumb cut, where the rafter will meet the ridge board. Therefore, the pitch of the valley rafter is 12-in-17. of run for the valley rafter to rise the same distance that the common rafters rise in 12 in. The run of the valley rafter is longer than the run of the common rafters, so it takes 17 in. Once I have the run of the common rafters, I use the calculator to find the lengths of all the rafters. The run of the common rafters is equal to half of this measurement, less half the thickness of the ridge board. I measure the width of the building first, including the sheathing. A valley rafter follows the line of intersection between a main-roof surface and a gable-roof addition or a gable-roof dormer surface. Consequently, they are the same length as the hip rafters. This places them parallel 10 the hip rafters. The second thing that I need to know is the total run of the common rafters.Īs a house is framed, measurements can vary slightly from the design, so I disregard the plans when finding the run of the common rafters, and instead take my own measurements. Valley Rafters Valley rafters run at a 45 angle to the outside walls of the building. On this project, the roof is a 12 pitch, or 12-in-12. ![]() To get started, I need to know only two things. Then I use a construction calculator to find the correct length of each rafter. To understand the concept and how all the pieces are laid out and cut, I picture the roof two dimensionally, in plan view. If you begin with accurate, as-built measurements and use a construction calculator to do the math, you can cut all of the rafters for most roofs on the ground in just one shot. ![]() Here, contributing editor Rick Arnold takes readers through the process step by step.įraming a complex roof is one of the trickiest parts of home building. ![]() Synopsis: If you begin with accurate, as-built measurements and use a construction calculator to do the math, you can cut all of the rafters for most roofs on the ground in just one shot. ![]()
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