A roof overhanging an exterior door provides a high degree of protection from the elements, both for the door and anyone using it. While the overhang will not protect anyone from side winds, it helps to keep the rain and snow off anyone standing at the door; which makes finding your keys when coming home from work in the rain or during a snowstorm less unpleasant experience.
Measure the width of the door frame using a tape measure and add 2 feet to this number to find the width of the roof you will build. Cut three pieces of 2-by-4-inch lumber to this length using a circular saw. Cut two more pieces of 2-by-4-inch lumber 18 inches long.
Draw a 1-by-1-inch square on the ends of the 2-inch wide faces of two roof width pieces and both 18-inch-long pieces using a pencil and ruler. Cut these squares out using a jigsaw to leave 1-by-1-by-4 inch notches in the lumbers. Screw the notched lumbers together to form a rectangle using a hammer drill and screwdriver drill bit to seat 2 countersunk 6 inch screws per corner joint.
Lift the remaining roof width lumber onto the wall 12 inches above the door frame and center lumber over the door so there is 1 foot of wood on each side of the frame. Drill holes through the lumber and into the wall every 6 inches along the length of the lumber. Fit a wall plug into each hole in the wall. Screw the lumber to the wall using 6-inch-long screws.
Lift the rectangle so it sits on top of the door frame. Drill holes at 6-inch intervals through the lumber pressed against the wall and into the wall itself using the hammer drill. Fill the holes in the wall with wall plugs. Screw the rectangle to the wall using 6-inch-long screws. Set up a step ladder on the ground inside the rectangle to gain easy access to the overhang.
Cut two pieces of 2-by-inch lumber 8 inches long. Screw one two-by-four on either side of the roof overhang between the top piece and the rectangle using two equidistant 6-inch-long screws per piece. Ensure both pieces of wood are flush with the edges of both the top piece and the rectangle. Screw the two-by-fours to both the top piece and the rectangle using L-brackets.
Measure the distance from the top of the top piece of wood to the frontmost edge of the rectangle, and add 8 inches. Cut enough strips of 2-by-4-inch timber to fit one strip to the roof every 4 inches using a circular saw.
Stand the first strip on top of the top bar and the front of the rectangle. Use a pumb line to draw a line on the end of the wood to make it sit flush with the wall. Repeat with the other strips. Cut the strips along these lines. Stand the first strip on the bar and rectangle again, flush against the wall.
Draw a line vertically up the two-by-four from the point where it connects with the front of the top bar, using a pencil and ruler. Repeat this process where the two-by-four connects with the frontmost edge of the rectangle. Draw horizontal lines bisecting the verticals line at the half way point. Repeat for the other 2-by-4-inch strips. Cut out notches in the two-by-fours along the lines you just drew using a jigsaw.
Stand the two-by-fours on the top bar and rectangle so the notches you cut make the lumbers stand flush with the top bar and rectangle. Space the two-by-fours to there is a 2-inch gap between each of them, with one lumber flush with either end of the roof. Screw the lumbers to the top bar and rectangle using 6-inch-long screws to form the roof braces.
Cut enough strips of one-by-two to place a strip across the braces with a gap of 3 inches between each strip. Standing on the step ladder, screw one strip of one-by-two to the top of the roof, flush with the wall, using 3-inch-long screws. Screw a second strip to the bottom of the roof, flush with the end of the 2-by-4-inch braces.
Screw the other 1-by-2-inch strips between the first two, leaving 2-inch gaps between each strip. Cut strips of underfelt as long as the width of the roof. Nail the first strip to the roof flush with the lowest edge of the roof, using 1/2-inch-long nails. Nail the second strip to the roof so it overlaps with the first strip by 1 inch. Continue to nail down underfelt until the roof is covered.
Lay a row of tiles on the roof, flush with the edge at the bottom of the roof. Nail the row of tiles to the roof using the tile nails that came with the tiles. Lay a second row of tiles above the first, so they overlap with the first row by 1 inch. Nail down a third row, again with a 1 inch overlap. Repeat until you reach the top. Nail down the final row.
Cut strips of fascia to the width of the sides of the roof. Screw the fascia to the wood frame visible on the sides of the roof, using 4-inch-long screws. Cut the edges of the fascia to fit the shape of the roof in order to fit the fascia to slope of the roof line.
Cut a strip of fascia to the width of the roof. Screw the strip to the roof beams along the front of the roof. Cut strips of fascia to the depth of the roof. Screw the strips to the wood frame on the underside of the roof to cover the underside and protect it from the weather.