How to Install or Replace a Gutter Downspout

Home repairs and home improvement projects can be intimidating, but something like installing or replacing a gutter downspout is pretty simple and quite important to the well-being of your home.

Depending on your gutter type, these steps may need to be adjusted, but overall, it’s a project that anyone can do. The materials are inexpensive, and most homeowners probably already have most of the tools they need to install new gutters or replace their old ones.

What is a Gutter Downspout?

Downspouts are basically drains for your gutter. These lightweight, vertical tubes connect to the underside of your gutters to carry water to the ground below. They are usually installed at any low point of the gutter system facing a suitable drainage area.

When it rains, rainwater travels down the roof’s slope and collects in the gutter. From there, the water runs to either end of the gutter and empties through the downspout. Some downspouts empty into rain barrels, while others take the water to an underground drain pipe. Generally, however, they just empty harmlessly into the yard and away from the house.

Downspouts have four main parts:

• The downspout itself

• A gutter elbow shaped like a macaroni noodle that connects the gutter to the downspout

• Downspout brackets or straps that secure the downspout to the building so it stays in place

• Downspout extension that attaches to the bottom end of the downspout, guiding water further away from your home.

The goal is to prevent water from pooling near the home so that it doesn’t saturate the ground and leach into the foundation. When water thaws and freezes, it can create cracks in the foundation, causing leaks in your basement or crawlspace and endangering the structural integrity of your home.

How to Choose Your Downspout

Downspouts are available in a variety of styles, sizes, and materials, including aluminum, vinyl, PVC, and stainless steel. When choosing your downspout, consider the size of your roof, the volume of the gutter, and the quantity of rainfall you expect during rainy months.

Each type of downspout has advantages and disadvantages. Here are the two main downspout styles:

Rectangular downspouts: These downspouts are the most common on modern homes. They have an angular shape and are are typically 2 by 3 inches, 3 by 4 inches, or 4 by 5 inches.

Pros:

• Easy to install because they lay flat on the wall
• Match most gutter styles

Cons:

• May not look as nice with half-round gutters

Round Downspouts: This downspout shape typically comes in 2, 3, and 4-inch sizes. You may be required to install a round downspout if your home is historic or in a historic neighborhood since many homes built before 1960 featured round downspouts. However, it also looks good on modern homes.

Pros:

• Looks good with many gutter styles, especially half-round gutters
• Matches both historical and modern homes

Cons:

• More difficult to install
• Tend to be more expensive

Both rectangular and round downspouts come in smooth and corrugated varieties. Corrugated downspouts are best for colder climates because they can expand if they freeze. Smooth downspouts are sleek, but it will be more obvious if they’re dented.

You should choose a larger downspout to lessen the chance of it being clogged by leaves and other debris. Adding gutter guards will further decrease the chance of this occurring.

Whether you have steel gutters, aluminum gutters, or seamless gutters, it is recommended that you use the same materials instead of mixing and matching different types of gutter materials. For example, you shouldn’t attach vinyl gutters to a metal downspout. Use a metal downspout for a metal gutter, and so on. They won’t fit securely otherwise.

Tools You Will Need

You will need to gather your tools and materials before your downspout installation. Here’s a list of the essentials: 

• Ladder
• Cordless drill
• Round hole saw attachment for your drill the same size as the drop outlet
• Hacksaw
• Tin snips
• Sheet metal screws or rivets
• Downspout brackets or straps
• Masonry screws or wood screws, depending on the material of your home, to connect the downspout straps or brackets to the outside of the house
• A drop outlet (generally 2 ⅜ inches)
• Downspout extensions
• Gutter sealant
• Downspout
• Elbows

Before You Start

Map out where you would like your downspouts to be located and where they should drain. Here are a few general tips to keep in mind when planning out your downspout and drainage locations:

• You should have one downspout for every 40 feet of gutter
• Water should drain at least four to six feet away from the foundation
• Keep the end of the gutter away from any landscaping so as not to wash away or drown your plants

8 Steps to Install Gutter Downspouts

Step 1. Detach the Downspout

Unscrew and detach the old downspout from the drop outlet (also known as a downspout outlet). These outlets are small attachments that connect your downspout to the gutter, so water flows out of the gutter and into the downspout.

If there isn’t already a hole for a downspout outlet, drill a hole in your gutter using the round saw attachment on your drill. The round saw attachment is the same size as the drop outlet, so the cylinder will fit snugly in the hole you drilled.

Step 2. Place the Drop Outlet

Coat the lip of the drop outlet with the sealant and place it pipe-side down into the hole you made with the drill. Push the drop outlet down firmly into the gutter.

Step 3. Attach the Elbow

You will need two elbow pieces and a short length of downspout material. One elbow attaches to the drop outlet and another to the side of the building, with a short piece of downspout connecting the two elbows at a slanted angle so water flows through them.

Fit the first elbow over the drop pipe of the outlet. Make sure that the elbow’s other end is facing toward the house. Measure the distance between the end of the elbow and the wall to see how long the connecting piece needs to be, taking into account the size of the other elbow. Cut the piece to the correct length with a hacksaw.

Step 4. Measure and Cut

Measure from where the gutter is to the ground, then subtract around seven or eight inches to make room for the top and bottom elbows. Always get more downspout material than you need, just in case of mistakes.

Measure out the length of the downspout before cutting it with the hacksaw. Measure the distance from the downspout to the side of the building to determine what height you’ll be attaching the second downspout to the house. 

Step 5. Prepare the Gutter Extender

Cut your gutter extender to the correct length with the hacksaw. Downspouts should extend four feet away from your home, but this length varies from property to property and on how the ground is sloped.

Attach an elbow to the extender so you can attach it perpendicular to the downspout. If the downspout is aluminum, you will need to crimp each piece with tin snips to hold it together nice and tight until you’re done installing. Slide whatever part will go on top into the one below so everything stays watertight. Otherwise, water might flow out of the seams.

Step 6. Attach the Downspout 

It’s best to put all the parts together on the ground so that you don’t have to do it while you’re up on a ladder. Fit the downspout to the top elbows attached to the gutter, and attach the extender with an elbow to the bottom of the downspout. Each piece should go at least one inch into the connecting part. Then you can lift it up and fit it all into place. Double check that the parts on top slide into the parts below.

Step 7: Install the Bracket or Straps 

Wrap one strap around the downspout a foot or so below the top elbow and screw it to both sides of the exterior wall. Add another bracket about halfway down and a third at the bottom, just above the final elbow.

You might need a helper to hold the downspout in place while you attach the pieces and screw them in place.

Screws are better than nails because they hold tight and are easier to remove when you need to replace them.

Step 8. Screw the Gutter Sections Together

Use small sheet metal screws to fasten the gutter sections together.

Vinyl parts may require brackets to hold them together, and you can use caulk to help keep things in place. Keep in mind that if you do choose to use caulk, the parts will be more difficult to pull apart when they need to be replaced.

FAQ About Installing or Repairing Gutter Downspouts

When to Hire a Pro 

Why spend your free time screwing gutters and using hacksaws when you could hire an experienced gutter pro instead? If you’re looking for someone to take care of the hassle of installing downspouts, we invite you to check out gutter professionals available in your area. 

They know how to replace old gutters, do gutter repair, or install downspouts and have plenty of pro tips from their years of experience with drainage solutions.

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