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How to Install a Downspout to an Existing Gutter [9 Easy Steps]

Rainwater would erode the foundation soil and splatter dirt on the siding.

If rainwater frequently clogs your gutters, you can decide to install an extra downspout.

Downspouts can be added to your gutters with ease but that requires some tricks and skills. 

How to install a downspout to an existing gutter?

Initially, measure the gutter’s depth. After that, drill a hole and put the connector in place. Before connecting the elbows, the connection flange must be sealed to the gutter interior. Afterward, screw the gutter elbow in place. Then, secure the downspout straps. Lastly, screw-in the final elbow.

It was only a teaser. More on these solutions is coming up shortly. Curious to learn more? Then, go through this content.

Instructions for Installing a Downspout to an Existing Gutter

If your gutters frequently overflow after severe rains, you may want to consider installing an extra downspout. Determining the position of your new downspout is important when downspouting to an existing gutter. 

Gutter-to-wall measurement and gutter-to-ground measurement are required. Using these two measures, you can estimate how much straight downspout you’ll need.

All you need is a downspout connector, three elbows, and a downspout.

This is not a detailed description I’ve added here. So for your clear information, you need to follow some instructions to install.

Before the step-by-step instructions, you need some materials to get the job done. 

So, check them down below!

Materials Needed

  • A downspout
  • Ladder
  • Tape measure
  • Screws to mount bracket to house
  • Mounting brackets
  • A pencil or a sharpie.
  • Elbows: number varies by setup
  • Gutter seam sealant
  • Straight hacksaw to cut holes for the outlet
  • Downspout outlet
  • Drill, screwdriver bit, drill bits. 
  • Hacksaw to right-size parts
  • Rivet tool

Step 1: Measure the Gutter’s Bottom

First, place the downspout installation ladder directly beneath the location you intend to use. A tape measure and a pencil indicate the gutter’s bottom at a distance. The distance should be four inches from one of the gutter’s outside corners.

Step 2: Drill the Hole and Position the Connector

Next, use the drill attachment to make a 1-inch hole in the gutter’s bottom at the 4-inch mark. You can use m7 or m42 drill bits here for doing the drilling process. 

Get a pencil to create a mark on the connector’s exterior. Do it until the connector has been positioned correctly.

Step 3: Install the Connector

Sheet metal cutters can be used to cut the connector’s trace. Use a shop rag to remove any debris from the gutter around the hole. Ensure that the area is totally dry before proceeding. To install the connector, place the connector’s inner lip inside the gutter.

Step 4: Seal the Gutter’s Interior the Connecting Flange

Using a cordless screwdriver, fasten the connector’s lip with 3/8-inch sheet metal screws. Do it from beneath the gutter. It will secure it to the gutter. 

Seal the gutter’s interior and the connecting flange in aluminum sealant with a caulking gun. Make sure that your caulking dries faster. Otherwise, the aluminum sealant won’t stick strongly.

Step 5: Place the Elbows to the Connector

The first elbow should be attached to the first connector. Then, using a single sheet metal screw, fasten the elbow to the connector. Connectors under the gutter will allow the elbow to slip around the elbow 6 inches. That should be below the bottom of the first elbow. 

Place the second elbow against the house. Start at one elbow and work your way backward to find the curve’s starting point.

Here are two recommendations for elbows. You can easily choose between these:


These elbows are best in the market. In addition, your local store should carry these. Also, they’re reasonably priced.

Step 6: Put the Screws on the Gutter’s Elbow

In this step, first, measure the length of the straight downspout. Then cut it with a hacksaw following your specifications. Make a house elbow out of the straight piece. 

Then fasten it with one sheet metal screw-on both the front and back of the elbow. Insert the straight piece’s other end into the elbow of the gutter. Put two sheet metal screws in it after that.

Step 7: Connect the Downspout to the Elbow in the Wall

Using a tape measure, measure from the elbow of the wall to the bottom of the floor. Straighten out the downspout using a hacksaw by subtracting 8-inch from the measurement. 

Using two sheet metal screws, connect the downspout to the elbow in your wall. Then tighten it in place.

Step 8: Secure Downspout Straps

Install downspout straps on the house every 10 feet. One screw should be used to attach the first strap. Attach it to the house beneath the downspout, two feet above ground level. 

Using a sheet metal screw, fasten the downspout strap to the downspout with a curve. Use a pair of sheet metal cutters to remove any extra strap.

Step 9: Fasten the Final Elbow with Screws

Use sheet metal screws to fasten the final elbow to the downspout’s bottom end. Put a splash block under the downspout to direct the rainwater away from the home.

Hopefully, now you can install a downspout to an existing gutter by yourself. Just don’t be panicked while you’re doing the work. 

While doing the installation procedure, your outside wall’s plaster can be damaged. In that case, plaster walls need to be remade. If things go wrong don’t delay seeking help.


What’s the best way to hang gutters?

Answer: Half an inch per ten feet is the usual rain gutter slope. This means you need to do it at every 10-foot point until you reach the downspout. Your gutter should be a half-inch shorter in height.

Is slotted guttering effective?

Answer: In the industry, conventional gutters have the same effective carrying capacity as slotted gutters.

What is the difference between a slotted and an unslotted gutter?

Answer: The cross-sectional area of gutters with optional slots is less than that of gutters without slots. Slotted gutters carry less weight than non-slotted gutters of the same profile.


You now know how to install a downspout to an existing gutter.

DIY gutter replacement can save your money over professional gutter installation. Before installing gutters, inspect the fascia and soffit for rotting wood to replace.

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Have a nice day!