 by Barry D. Mussell
Preface
Roof framing is the most challenging and difficult part of carpentry. A complicated roof can leave even an experienced carpenter scratching his head in confusion. Carpenters are a resourceful bunch and will usually find their way, but it is important to realize that framing is not a standardized practice. Carpenters will typically use several different methods to get their rafter lengths and framing points. Some will "step-off" rafters with a framing square, or use the "length per foot of run" on the steel square. Others may use a rafter table or a calculator, and some may simply string line and measure. Any of these methods will eventually get the job done, but why take the long way home?
The Roof Framers Bible provides all the information needed to frame any roof from simple to complex, all in an easy-to-use format. You no longer need to struggle with any roof, not even those difficult "Bastard" roofs. This guide makes them simple. In a matter of minutes you can have all the information needed to cut every common, hip, valley, and jack rafter in an entire roof. This compact durable guide also gives all the necessary miters, bevels, and sheathing cuts, unlike those expensive calculators which can only provide rafter lengths. Easy-to-use rafter tables provide the speed and accuracy of math, but without all the headache. The various "factors" throughout the book give one-step answers to problems which normally would require long series of mathematical calculations.
Take time to read over the first 35 pages to understand the methods used in this book. Doing so will help you to receive the full benefit of the information provided in the tables. There are a variety of different charts in this book. Often the same bit of information can be obtained from several different charts. Read the text and then experiment to find the method with which you are the most comfortable.
The key difference in this guide from others which you may have used is that when using the tables for the irregular hip roofs, you figure the rafter run from the end of the rafter tail instead of from the birdmouth. This is due to the different plate heights used on "Bastard" roofs. A full explanation is given on page 25.
The rafter tables are divided into three parts:
First - Complete rafter tables for the 14 most common equal-pitched roofs (3/12 thru 16/12). These are the rafter tables with which most carpenters are familiar. An additional rafter chart for less frequently used pitches (those below 3/12, over 16/12, or in 1/2 pitch increments) is given in the appendix on page 220.
Second - Rafter tables for 68 different combinations of irregular or "bastard" hip roofs - (non 45º).
Third - Rafter tables for 5 different polygon roofs (hexagon, octagon, etc.).
Also included is information on laying out ellipses and arches, framing roofs with a non-centered ridge, helpful math formulas, and an appendix of charts and conversion tables. Included in the appendix are charts giving the diagonals of rectangles. These are useful for squaring up foundations or wall plates, especially on those odd shaped sizes which cannot use the 3-4-5 triangle. You'll have the diagonal dimension of rectangles up to 50 feet by 72 feet, faster than you can punch in the numbers on one of those expensive calculators.
Note: All rafter dimensions from the tables are given in inches to avoid having to convert back and forth between feet and inches, and to make it easier to use a calculator.  If at any time you wish to convert to feet, the conversion table is on the last page of the book. Please note that the dimensions given in the tables are from exact mathematical formulas. If the walls of the structure are out of level or out of square, the rafters may not fit properly. Always start from a level and straight plate line and everything will "fit like a glove".
The following abbreviations are used throughout:
- RL - Rafter Length
- H / V - Hip or Valley
- (SP) - Short Point of the Bevel
- (LP) - Long Point of the Bevel
- Hp - High Pitch
- Lp - Low Pitch
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