Install a waterproof membrane over the cricket sides and edges fastened to the cricket with a construction stapler.
Framing and roof crickets.
Always frame the cricket at the same pitch as the roof and you will be within code guidelines.
Ok so a four foot wide chimney has a span of 4 foot and half of that is the run which is 2 foot.
In this example a pitch of 12 12 and 1 1 2 x 5 1 2 rafters are specified.
Put metal flashing along the sides of the cricket nailed in place to overlap seams with the roof.
Secure the plywood triangles to the roof decking and cricket ridge with galvanized screws.
You will need to use compound miter cuts for the cricket rafters.
Here the build roof dialog is being used to set the defaults for manually drawn roof planes.
This beam will provide the backbone for the cricket or saddle.
Select build roof build roof from the menu and in the build roof dialog specify the pitch framing and any other attributes that you will need for the cricket.
2x8 sleepers should be nailed to the roof surface to pick up the ends of the rafters.
The cricket or saddle basically rests on top of the house roof to visually extend the porch roof gracefully into the house roof.