Roof Framing Geometry

Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape.

Roof framing geometry.

There is more trigonometry in this book than all of the roof framing books written in english combined. The central angle for an octagon roof is 45. The tangent of 22 5 41421 laying out an octagon using a framing square we would take 12 on the blade and the number to be taken on the tongue is 12 41421 which is 4 97 or nearly 5. With overhang selected drag slider to increment decrement birdsmouth seat width to suit.

It will take more than just reading to understand roof framing geometry. Roof framing geometry trigonometry for polygons polygons in mathematical context polygons in carpenters mathematical context central angle pi 2 n working angle pi 2 n 2 plan angle pi central angle 2 exterior angle plan angle 2 s is the length of any side of the polygon n is the number of sides. There are smartphone apps available which can be used to sight a roof s pitch from the ground. One half of 45 is 22 5.

Roof framing geometry is empirical type knowledge. Information gained by means of observation experience or experiment. You ll need to draw out the roof framing geometry. However it has over 1 000 geometric roof framing drawings in the book as well for carpenters that are not comfortable using trigonometry.

The pitch or steepness of a roof is often referred to in terms of the amount of vertical rise over a 12 horizontal run. For complex roof framing trigonometry or geometry must be used.