A downspout drains water from a gutter. When you add a downspout to an existing gutter, it probably means you are not happy with the drainage of your current system. You can also add another downspout to serve as a back-up in case another downspout becomes clogged. Once you have established where you want to place the new downspout on the gutter, use a few basic steps to install it.
Place a sleeve under the gutter at the place you are adding the new downspout. A sleeve connects an elbow to the gutter. Trace around the sleeve with a pencil.
Drill four small holes into the corners of the tracing. Cut along the lines of the tracing with sheet metal sheers. File the edges of the sleeve to make them smooth.
Place aluminium sealant around the lip of the sleeve. Place the sleeve into the new hole. Press down to hold it in place. Attach the sleeve to the gutter with four sheet metal screws.
Attach an elbow to the newly installed sleeve so that it points straight down the house.
Measure and cut the new piece of downspout with a hacksaw. The downspout should reach from the elbow you just installed to 6 inches above the ground. Slide the new piece of downspout into the elbow.
Attach an elbow at the bottom of the downspout. Point elbow away from the house.
Place aluminium straps around the downspout and onto the side of the house. Place straps every 10 feet. Secure the straps with screws.