Many houses are built with a door access projecting from a cantilevered bay. In most cases, particularly in older construction, these bays are not built from continuous floor trusses running through the house. They are instead simply applied or tacked on to the side of the house. This means you cannot directly hang off this section of house. If you are working around a canted bay, verify your house's construction by checking your house plans or the house frame itself if you have an unfinished basement. You can always cut beam pockets into the house to provide bearing support or install posts and footings beside the house. But, why the hassle? The best and least invasive technique is to frame an H around the cantilevered bay.
This is done by installing two beams running perpendicular to the house from either side of the bay and running a beam between them directly in front of the bay. In essence, you are transferring the load off of the cantilevered bay through the beam set in front to the two perpendicular-oriented beams and finally to a solid part of the house. Use the proper joist hangers and fasteners to secure the framing. Because of the long spans across the bay, you may need to use a 3-2x10 beam.