For a good straight fascia, add an extra inch or 2 to the tails of all your rafters total. In this video i show you how to layout and cut hip and valley rafters. A jack rafter is a shortened common rafter that may be framed to a hip rafter, a valley rafter, or both. It is used to identify the centre line positions for the purpose of calculating rafter set out length and the rise of the roof.
Thus, there are hip jack rafters and valley jack rafters. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Three different procedures can be used to calculate common rafter length. How to calculate rafter lengths for gable, hip and valley rafters. Exact lengths of all rafters including all regular and irregular hips, valleys.
Complete instruction book and rafter length tables. Cant remember all those key strokes for the construction master calculator. This table provides the hip and valley factor for common roof pitches, as well as the underlying equation for the factor. The blind valley roof can be used to calculate valleys for roofs with unequal slopes. Hip roof framing calculator with rafter angle cutting. Hip roof framing rafter cut angle template diagram.
The heel height, overhang, and ridge and fascia boards for both roofs will be the same. Includes result for hip valley factor, slope factor and the roof slope in degrees. Calculate the length of a rafter from the roof slope ratio of inches per foot, and a building width measurement. Deduct half the thickness of the ridge from the span length this length is the correct measurement from the top plumb line to the birdsmouth plumb line. There is more trigonometry in this book than all of the roof framing books. For larger roofs though, i use a roofing ready reckoner.
It is believed, therefore, that this book will commend itself. Can they still layout and cut a hip rafter without the use of these tools. The hip and valley factor is a number that is multiplied by the actual run horizontal distance of a common rafter to determine the length of a hip or valley rafter. Rafterhip lengths where one pitching plates is higher than the other such as where part of a wall is extended to eaves and no bulkhead is used. Measure or calculate the horizontal distance the rafter.
Hip roof framing calculator with rafter angle cutting templates and setout plans metric. Each page has a different table depending on the pitch angle of your roof with all the figures you need. To remove this center ridge piece, you can lengthen 2 only opposing common rafters by and butt their tops together in the center. Hip valley line length ratio jack step down each rafter. There is no problem in laying out these angles on the rafters as long as you keep in. If using a circular saw or compound miter saw, set saw bevel angle to 45 to obtain creeper and hip side angles. How to layout and cut hip and valley roof rafters youtube. A ready reckoner is pretty much a rafter length calculator a book full of tables for working out the rafter. Irwin rafter square reference guide complete instruction book. A rafter that runs from a hip rafter to a valley rafter, perpendicular to the roof ridge.
How to calculate rafter lengths for gable, hip and valley. With a square roof, the ridge becomes a square center piece kingpost with side lengths equal to common rafter thickness. This clip from roof framing for the professional the essentials dvd series, discusses the most common reason correctly calculated hips dont fit in the real world and what to do about it. Roofcalc roof framing calculator for roofing carpenters. Find the bridge measure of the hip or valley rafter on the framing square refer to. Let this book make you an accomplished master of irregular pitched roof systems. Inch rise, run and the tables in the back of this book are all that are needed to layout rafter lengths and cuts for common, hip, valley and jack rafters. A ready reckoner is pretty much a rafter length calculator a book full of tables for working out the rafter lengths quickly and easily.
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