How to Install a Gutter Downspout

What You'll Need
Downspout Pipe
Self Tapping Screws
Hack Saw
Step Ladder
Elbow Joint (if existing one is being replaced)

If a gutter downspout on your home needs replacing, you will need the correct replacement parts and tools to complete the job accurately. Gutter downspouts serve a highly important function in the redistribution of water from your roofing gutters and they should be located correctly.

Step 1 – Measuring the Downspout

Always measure correctly the length of downspout you will need. Measure the length from the existing elbow joint to the existing exit point of the pipe. Also, measure, correctly the angled lean that the downspout has, as this will need to be duplicated with the replacement.

Step 2 – Cutting

Use a hacksaw to cut the right length of downspout required. Make the cut as clean and neat as possible and make sure it fits into the existing elbow joint, or replacement elbow joint, if you are changing that as well. Always do a dry fit of the pieces to be certain they will fit.

Step 3 – Preparing the Gutter

If the gutter has connecting pieces for angles from the soffits make sure that all pieces of connector have been cut accurately to cope with the correct angles of descent from the roof. Fit the connector tightly. There should be no gaps in the connections at all. Use sealant around the connector lips to ensure a waterproof joint.

Step 4 – Installing the Downspout

Slip the elbow joint onto the connector. Use self tapping screws to secure the joint. Slide the downspout into the joint hole and screw the two together. Then seal the joint with caulk sealant. Make sure the downspout is flush with the wall of the house. Place the level vertically against the downspout and ensure it is perpendicular. Do not use bands to hold the spout. These are no longer recommended and it is strongly advised that you use back brackets which attach to the back of the downspout to improve visual appearance of the finished downspout.

Step 5 – Bottom Part

When the downspout has been attached, make sure that there is a gap of about 2 inches from the ground. Any more than that and you are risking splashes and misdirection of the water. Affix another angled connector to the bottom of the downspout to face outward, allowing the distribution of water to go away from the house.

Step 6 – Checking the installation

When all brackets have been secured and the downspout is firmly in place, let all the sealed joints set thoroughly before testing. Use the right exterior sealant for guttering installation. When the sealant has dried and set you can test the gutter by spraying the roof guttering with water and test the behavior of the newly installed downspout. What should happen is that the water flows straight from the roof guttering into the downspout and to the bottom, flowing toward any downward land or drainage area. You should not see any water coming from the sealed joints.