Downspouts are straight, hollow tubes that run vertically along the exterior of buildings and connect to the gutters at the roof line. Water flows out of the gutter and through the downspout where it is directed onto the ground. If the downspout cannot go straight to the ground, or if you want to extend the bottom away from the building's foundation you must install elbows. Elbows are pre-formed curved sections that connect two straight pieces of downspout together.
Connect the Elbow to the Gutter
Place a ladder against the house directly under the gutter where the downspout will be installed. Insert an elbow up one inch into the bottom of the funnel-shaped opening on the gutter, which is called a gutter outlet.
Insert a 3/4-inch sheet metal screw through the front of the gutter outlet, using a screwdriver, so that it penetrates the elbow and holds it in place. Place two more screws on the sides of the gutter.
Grasp the bottom circular edge of the elbow with a pair of needle-nose pliers and bend it inward approximately 1/4 inch. Repeat the process to crimp the entire edge of the elbow, as this will help the elbow adhere to the downspout.
Connect the Elbow to the Downspout
Insert the straight downspout up into the bottom crimped edge of the elbow, as far as it will go.
Insert three more sheet metal screws on each side of the elbow, to secure it to the downspout.
Climb down the ladder and pick up another elbow. Crimp both ends of the elbow with the pliers, just as you did in Section 1, Step 3.
Slide the elbow into the bottom end of the downspout---as far as it will go---making sure that the bottom opening of the elbow points away from the building. Insert additional sheet metal screws through the elbow and the downspout.
Lay another straight piece of downspout on the ground; be sure the piece is at least five feet long. Slide it into the free edge of the elbow, until it stops. Secure the edge with three more screws.