verkanteter Kehlsparren auf spitzwinkligem Grund
Canted Valley Rafter on Acute Angled Ground Plan
This task model is basically the same as the Canted Valley Rafter on Rectangular Ground Plan task model. The geometry is fairly straightforward after studying the geometry for the canted valley rafter on a 90° ground plan.
Drawing the valley rafter backing triangle is not in the book, but it's my way of making sure I've drawn the canted valley rafter footprint correctly.
Here I used the German technique "Ausbaukante", expansion form the bottom edges of the profile rafters to locate the bottom edge of the canted valley rafter. In the last model I centered the canted valley rafter and the jack rafter claws protruded below the bottom edge of the canted valley rafter. By using the Ausbaukante technique in the book, the jack rafter claws do not protrude below the bottom edge of the canted valley rafter.
Witches cut plane in #d.
Witches cut angles.
Bottom of jack rafter claws flush with the bottom of the canted valley rafter.
Drawing for developing the witches cut planes on the ground plan and roof surface.
Drawing with the valley rafter shadow line for developing the cutting direction of the jack rafter lower claw.
The new book on the ancient knowledge Roof Framing by Bernd Küppers