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A solid gutter system and a few firmly attached downspouts are key to a dry roof and moisture-free foundation or crawlspace.

Yet, if your downspouts barely keep the drained water away from your house by a few inches, heavy rainfall could easily cause the water to gather near the structure.

Don’t fret if this is the case with your property; you only need to install reliable downspout extenders to solve the problem. Here’s our hassle-free guide on how to drain gutters away from your house!

Do Downspout Extensions Work?

Yes!

In short, downspout extensions are useful attachments that direct the water away from a house’s foundation so that it drains at a safer distance. These extenders are usually available in a wide variety of materials, like PVC and vinyl steel.

Downspout extensions do a magnificent job of ensuring no rainwater puddles around your house if you live somewhere susceptible to heavy rain. They’re essential for properties with landscapes that are angled in a way that allows the water to accumulate around the foundation.

While many people might argue that splash blocks can also work in this scenario, they’re only good enough for slowing down the impact of the water. They don’t help with accumulation, which is why you’re still better off installing a downspout extender.

How to Extend a Downspout

Thankfully, the process of installing a downspout extension is pretty straightforward, even for those who aren’t skilled in the DIY world. Here are a few guidelines that can set you on the right path when it comes to assembling downspout extenders.

Step 1: Measure Your Downspout’s Opening First

Before you head over to your nearest hardware store, you need to get the measurements of the bottom part of your downspouts. Without this step, you risk a flimsy fit that could cause leaks, which defeats the purpose of an extension!

Chances are your downspout outlet is 2 x 3 inches or 3 x 4 inches if it’s rectangular or attached to a K-Style gutter. Otherwise, it could be 3, 4, or 5 inches in diameter in case of a round downspout.

Step 2: Shop for the Right Size Downspout Extension

Now that you know the size of your downspout outlet, you can buy an attachment that’s specifically designed for this size. You won’t have to do much digging, as these extensions are all over big box hardware stores with downspout sizes already written on the packaging.

Even better, many downspout extenders are easy-to-assemble or pre-assembled. Others are made up of just one part that you get to roll out once the rain starts falling.

Some downspout extensions come with snap-on mounting, too, to give you maximum convenience as a user.

Step 3: Attach the Downspout Extension to the Elbow

Now, you can fit the extension into the downspout’s elbow. Or, you may remove the elbow entirely and connect the extension to the bottom part of the downspout.

Again, how you approach this step depends on the design and assembly method of each extension. So, always refer to the manufacturer’s guidelines and follow the instructions to attach the downspout extension.

After that, allow some water to run into the downspout to test the extension for leaks and make sure the water doesn’t go backward. Adjust the extension’s angle as necessary until you achieve the desired result.

If the extension ends up being too long with no way to adjust it to make it shorter, you can cut the downspout using a hacksaw. Otherwise, you may use the help of a professional for a cleaner cut.

Step 4: Seal the Connection Between the Downspout and the Extension

Leaving things as they are isn’t the best course of action because an unsealed joint between the downspout and extension may lead to leaks or blockages in the long run. It might also lead to the extension becoming loose with constant wear and tear.

This is why we advise you to seal that joint using Zipp screws to keep it from popping off with pressure. However, ensure these screws aren’t longer than half an inch to prevent clogging.

How Far Should Downspouts Extend From the House?

The length of your downspout extenders heavily depends on the type of soil you have in your yard. That’s because different soil types vary in their drainage abilities, and you don’t want to mistakenly flood your lawn!

As a rule of thumb, clay soils on sloped land will require you to direct your gutter water at least three feet away from your house’s foundation. If the area is flat, you’d better go with ten feet for high clay content or even more for sandy soils.

How to Extend a Downspout Underground

If you don’t want to leave anything for chance, running your downspout underground is your best shot at zero water accumulation near your house. For this DIY project, you’ll need:

Downspout filter
45-degree-angle PVC joint
Plastic SDR-35 sewer pipe (4 inches in diameter and 4–8 feet long)
PVC T-connector
PVC filter

Then, follow these steps to understand how to extend a downspout underground:

For each downspout, dig a trench that stretches for a length of around ten feet, with a width of six inches and a depth of 12 inches.
Create a slight slope so the water easily flows through the pipe, dropping the trench ⅛ inch per foot.
Connect the PVC joint to the end of the sewer pipe, adding PVC glue where their ends overlap and twisting them into a snug fit.
Attach the downspout filter to the other end of the angle fitting, then hold that end next to your downspout so that it’s above the ground.
Mark that spot to cut it using a hacksaw or tin snips.
Attach the filter to the downspout itself, keep it steady to the house’s siding using screws, then slide the angle joint onto the bottom part of the filter.
Secure them with PVC glue.
With the sewer pipe lying in the trench, consider packing some dirt under it to adjust its position as you see fit.
Under the end of the sewer pipe, dig a three-foot-deep hole, then line its bottom with gravel.
Slide the T-connector into the open end of the sewer pipe, ensuring that it’s going up and down on the pipe and attaching a PVC filter on the top opening of the connector.
Make sure that the top part of the T-connector is at the same level as the ground.
Cover the trench with dirt and even out the ground.

Now, any rainfall that goes through your downspout will be collected in the gravel-lined hole first. Then, any excess water will flow outside the pipe and into the ground.

Final Thoughts

Downspout extensions go hand in hand with a durable guttering system to keep your foundation safe from water accumulation.

Thankfully, learning how to drain gutters away from your house isn’t that hard. Just follow the steps we’ve listed out earlier, and your DIY project should be a breeze!

Ben Esman

Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.

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