How to Add a Roof Over the Front Door

Measure the width of the door using a tape measure and add 12 inches. Cut three 2-by-4s to this length using a circular saw. Cut two 2-by-4s to a length of 12 inches. Hold one of the door-width pieces against the wall just above the door so there are 6 inches of wood on each side of the door. Drill holes through the wood and into the wall every 6 inches along the length, using a hammer drill.

Fill the holes in the wall with wall plugs. Screw one of the 12-inch pieces to either end of the drilled wood using two countersunk 2-inch-long screws per piece, to form a U shape. Screw another door-width piece to the other end of the 12-inch-pieces in the same manner, to form a rectangle as long as the width of the door plus 12 inches and 16 inches wide.

Screw the rectangle to the wall via 6-inch-long galvanized screws in the holes you drilled. Hold the remaining 2-by-4 piece horizontally across the wall 12 inches above the top of the rectangle. Drill holes through the wood and into the wall every 6 inches along the length of the wood. Fill the holes in the wall with wall plugs. Screw the wood to the wall using 6-inch-long galvanized screws.

Measure from the wall just above the top 2-by-4 piece and diagonally down to the outer edge of the rectangle. Add 6 inches to this measurement to find the length of the joists you will need. Cut enough 2-by-4 lumber to make one joist at either side of the roof and one joist every 6 inches between.

Stand the joists on the rectangle and top piece with the 4-inch sides of the joists vertical and the corner of one end touching the wall. Hold a plumb line to the top corner on the side by the wall on each piece. Draw a vertical line down the plumb line with a pencil. Cut along the lines using a jigsaw, to allow the joists to sit flush with the wall.

Stand the joists on the rectangle and top piece again. Use the plumb line to draw vertical lines down the joists at each point where they connect with the rectangle and top piece. Draw a horizontal line bisecting these lines using a ruler. Cut out the notches formed by the lines using the jigsaw.

Stand the joists back on the rectangles and top pieces, with the notches allowing the joists to sit flush against the wood. Screw the joists to the rectangle and top piece using one countersunk 6-inch galvanized screw per joint.

Cut enough pieces of 2-by-2 lumber to sit one piece as a crossbeam every 4 inches down the length of the joists. Screw the 2-by-2 pieces across the joists with one 3-inch-long screw per joint. Leave a 2-inch gap between each crossbeam.

Cut strips of underfelt to the width of the roof line. Nail the first strip to the bottom of the roof line using clout nails and a hammer. Nail the second strip above the first with a 1-inch overlap. Continue nailing the underfelt to the roof until the roof is covered.

Nail the first row of slate roofing tiles to the bottom of the roof using 1-inch-long roofing nails. Lay the second row above the first with a 1-inch overlap. Alternate nailing and laying rows of tiles until you reach the final row. Nail the final row to the top of the roofline.

Cut a sheet of 3/4-inch-thick plywood 20 inches long and 12 inches wide. Cut a diagonal line across the sheet using a jigsaw or circular saw, to form two right-angled triangles. Screw one triangle to either side of the roof using 1-inch-long screws.

Cut a sheet of 3/4-inch-thick plywood as long as the width of the roof and 16 inches wide. Screw the sheet to the underside of the roof using 1-inch-long screws. Varnish the front, sides and underside of the roof using exterior-grade varnish and a paintbrush.