Do not check build roof planes.
Framing and roof crickets.
You will need to use compound miter cuts for the cricket rafters.
This also makes it easier.
The cricket or saddle basically rests on top of the house roof to visually extend the porch roof gracefully into the house roof.
Install a waterproof membrane over the cricket sides and edges fastened to the cricket with a construction stapler.
Always frame the cricket at the same pitch as the roof and you will be within code guidelines.
Here the build roof dialog is being used to set the defaults for manually drawn roof planes.
2x8 sleepers should be nailed to the roof surface to pick up the ends of the rafters.
Put metal flashing along the sides of the cricket nailed in place to overlap seams with the roof.
In this example a pitch of 12 12 and 1 1 2 x 5 1 2 rafters are specified.
This is the number which we will use to lay out our rafter for the cricket.
Ok so a four foot wide chimney has a span of 4 foot and half of that is the run which is 2 foot.