Step 1
Measure and mark the outline of the area that will be covered by the overhang.
Step 2
Connect three boards with screws to frame the overhang outline. Attach to an exterior wall of the pole barn with screws to complete the outline framing.
Step 3
Dig post holes at the frame corners opposite the pole barn wall with an auger. Holes should be at least five feet deep. Insert a 4-by-4-inch post in both holes and fill with concrete mix. Fill the frame with concrete for a level surface under the overhang.
Step 4
Measure the distance from the edge of the pole barn roof to the far edge of the 4-by-4 post. Add 18 inches to the measurement and cut a 2-by-10-inch beam to that length.
Step 5
Place a 2-by-4 board across the 4-by-4 beams to connect the overhang posts. Count the number of pole barn roof trusses between the edges of the overhang outline and cut enough 2-by-10 inch boards to the length determined in the previous step to attach to each truss.
Step 6
Remove the fascia from the pole barn roof trusses, if present. Attach each board cut in the previous step to a roof truss with a rafter tie and nails or screws.
Step 7
Cover the exposed end of each 2-by-10 inch beam with fascia board.
Step 8
Attach tin roofing sheet to each 2-by-10-inch beam with roofing nails to cover the area beneath the overhang.