How to Add a Lean-To on a Front Porch

Floor Construction

• 1

  Cut the necessary pieces of 2-by-4-inch lumber for floor construction. This requires two 6-foot pieces and six 4-foot pieces.

• 2

  Form a square with the two 6-foot pieces and two of the 4-foot pieces. Space the rest of the 4-foot pieces 16-inches on center to complete the grid. Mark the position for each board.

• 3

  Nail the floor pieces together with 16d nails, using the marks to find the correct position if the boards are moved.

• 4

  Cut two 6-foot pieces from 4-by-4-inch lumber. Set these pieces on the ground, spaced 4-feet apart in the desired location for the lean-to. Leave the pieces a few feet from the outside wall of the house so there is still access to the back of the lean-to.

• 5

  Set the floor frame on the 4-by-4s and nail the floor joists to them to secure.

• 6

  Nail 3/4-inch plywood over the floor joists to complete the floor.

Back Wall Construction

• 7

  Cut all the necessary pieces of 2-by-4-inch lumber for the back wall. This requires two 6-foot pieces and four 8-foot pieces.

• 8

  Lay the two 6-foot pieces on a flat surface, narrow sides up.

• 9

  Cut an 18-degree angled miter cut at one end of each of the 8-foot boards.

• 10

  Set the four 8-foot pieces between the 6-foot pieces with the mitered ends facing the same direction. Set one board at each end and space the other two boards 18-inches on center.

• 11

  Set the wall in place and check that the wall is square. Nail in place into the floor joists. Use spare 2-by-4s to brace the structure while the rest of the lean-to is assembled.

Front Wall Construction

• 12

  Cut all the necessary pieces of 2-by-4-inch lumber for the front wall. This requires one 6-foot piece, two 1-foot pieces, four 81 1/4-inch pieces, two 51-inch-long pieces and two 6 1/4-inch pieces.

• 13

  Line up two of the 81 1/4-inch wall stud pieces with the 1-foot boards. The outer edge of the studs lines up with the outer edge of the 1-foot pieces. Nail the pieces together through the bottom of the 1-foot boards and repeat with the other set of wall studs.

• 14

  Line up the 6-foot board with the opposite end of the wall studs and nail together.

• 15

  Nail the two 51-inch boards together to create a doubled header for the door frame. Measure 71 1/2 inches from the bottom of the front wall frame and nail in place between the two inner wall studs. The bottom of the doubled header is 71 1/2 inches from the bottom of the frame.

• 16

  Tap the 6 1/4-inch pieces into place between the doubled header and the 6-foot top plate with a hammer. Ensure the two pieces are evenly spaced. Nail these pieces in place to complete the front wall. This framing allows room for a 4-foot-wide door.

• 17

  Set the front wall in place on the shed floor and nail down through the floor joists. Brace the structure with spare 2-by-4s while you continue the build.

Side Wall Construction

• 18

  Cut all the necessary pieces of 2-by-4-inch lumber for the two side walls. Each side requires two 41-inch pieces and three 81 1/4-inch wall stud pieces.

• 19

  Nail the 81 1/4-inch wall studs into the 41-inch top and bottom plates to form each wall.

• 20

  Raise the side walls into position on the floor of the shed. Nail in place through the floor joists.

• 21

  Check that all the sides are square. Screw each of the walls together at the corners until stable.

Roof Construction

• 22

  Cut the ends of the 2-by-4 roof rafters so they line up with the wall studs for the front and back walls. Dry fit the boards first, making angled cuts at the ends so the boards rest comfortably on the top wall plates.

• 23

  Cut a gable stud to fit between the rafter and the center stud of each side wall. Tap into place with a hammer and nail to secure.

• 24

  Nail a 6-foot piece of 2-by-4 sub-fascia to cover the front ends of the rafters.

Finishing the Lean-To

• 25

  Cut T1-11 siding to cover the side and front walls. Secure to the wall studs with 8d nails every 8 inches. Ensure that the siding is even with the bottom of the floor joists.

• 26

  Cover the back wall with 1/2-inch plywood nailed into the wall studs with 8d nails spaced 8 inches apart.

• 27

  Cover the rafters with 1/2-inch plywood secured in place with 8d nails spaced every 8 inches.

• 28

  Cover the roof with roofing felt. Apply your choice of roofing material, such as asphalt shingles or choose a roofing material that matches your house.

• 29

  Construct the door using two 4-foot-long 2-by-4s for the top and bottom plates and two 71 1/2-inch 2-by-4s for the sides. Cover the front of the door with T1-11 siding. Add trim if desired.

• 30

  Attach the door to the shed with decorative strap hinges and install a latch and lock.

• 31

  Slide the lean-to into its final position on the porch. The lean-to was placed away from the house to allow room to access the back wall.