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Why Should You Invest in Underground Downspouts? 

Drought is part of life when you’re living in Colorado, there’s no way around it. For that reason, it might seem like gutters and downspouts aren’t really serving much of a purpose.  

Drought eventually has to end, and when it does, your gutters and downspouts will start capturing tons of water. However, as you can see in the image, most normal downspouts end up expelling water right next to the base of your home, which can lead to foundation damage.  

In this guide, we want to provide you with as much useful information on underground downspouts (also known as buried downspouts) as possible, and why investing in them is an effective way to keep your home safe from damage. 

Let’s dive into it.  

Water Accumulation After Rain or Snow

First, to understand the value of a gutter system with underground downspout extensions, we need to start by looking at how much water tends to accumulate around an average-sized home after it rains.  

Rainfall on a 1,600-square-foot home 

Surprisingly, a single-story single-family home with 1,600 square feet will accumulate nearly 1,000 gallons of water after just one inch of rain.  

That means if there’s a storm that brings a foot of rain with it, there would be nearly 12,000 gallons of water falling on that same home’s roof. You can see from this chart why a high-quality gutter system is important. 

  • 1″ of rain: 997 gallons of water 
  • 5″ of rain: 4,984 gallons of water 
  • 12″ of rain: 11,962 gallons of water 

Steepness of the Roof 

Keep in mind, the steepness of a home’s roof will also affect the amount of rainwater captured by a gutter system. For example, one inch of rainfall could translate to 1.25 inches of water collected by gutters because of the roof’s angle. 

Potential Risks Without Underground Downspouts 

After rain or snow, your gutter captures the water, but where does it go? Water moves through the gutters toward downspouts located at different points around your home.  

Unfortunately, many downspouts expel water directly into the soil just a foot or two away from your home. This can end up causing foundation issues, especially in Colorado where bentonite clay is a common soil type.  

When water drains from the downspout and into the soil in your yard, it has the potential to cause the following problems: 

That’s because most of the soil in Colorado is extremely expansive. When water of any kind is absorbed by bentonite, it swells up and the soil particles increase in size. 

Quickly, the ground surrounding your foundation begins to push against the structure and causes the structural problems we mentioned.  

Installing underground downspout extensions helps avoid expansive soil and foundation damage. Additionally, they provide added benefits to your entire property. We’ll cover these in the next section. 

Benefits of Underground Downspouts 

Reduces Water Damage 

First and foremost, underground downspouts protect your home from water damage by moving captured rain and snowmelt far away from the structure.  

Buried downspouts work best when they extend at least 10 feet away from the home. At this distance, water from the gutters won’t be able to drain next to foundation walls which lowers the chances for water damage immensely.  

Protects Landscaping 

During particularly heavy rain or snow, your downspouts end up ejecting more water than usual. Sometimes, so much water comes out that large puddles can form right near the downspout.  

All this water can pose a risk to your property as it builds up, potentially killing grass, shrubbery, and other plants near the affected area. Any concrete (including the foundation) on your property could also be affected. 

If too much water is poured onto concrete, it could start to crack, sink, or crumble over time. Underground downspout extensions help you avoid damage to landscaping in your yard.  

Avoids Soil Issues 

As mentioned earlier, bentonite soil is the most prevalent soil type in Colorado. When water is absorbed by this soil, it grows in size. Any bentonite near your foundation can expand and cause damage if downspouts drain water close to your home.  

Keep in mind, some parts of Denver have sandy, rocky soil which faces a different issue without proper downspout drainage. When water oversaturates this type of soil, it faces erosion and washout.  

Essentially, this means parts of the soil are moved away and broken down. This is a problem because the soil becomes weakened and unable to properly support your foundation, which leads to damage.  

Installing Buried Downspouts 

Installing underground downspout extensions is a job best completed by professionals because the process involves a lot of digging and measuring. Whether you work with Groundworks or another company, here’s what you should expect from a trusted professional.  

1. Dig a Sloped Trench 

Before any downspout extensions can be installed, the team needs to dig corresponding trenches. They will be dug at a slope to ensure water keeps moving after exiting the gutter system.  

These trenches will house the underground downspout and provide a pathway for the extension to carry water safely away from your home. Don’t worry, these will be filled back in at the end of the process.  

2. Attach the Extension 

Once the digging is completed, the underground downspout will be attached to the original downspout and laid out along the trench. Most downspouts extend between 10-50 feet depending on your needs.  

Based on how long you need each extension to be, there could be multiple sections to your downspout. Either way, a professional team will have the tools and resources to accomplish this. 

3. Backfill the Trench 

After the extension is attached and placed in the trench, the ground will need to be refilled so the downspout is covered.  

Keep in mind, if a trench is refilled with bentonite clay, it will face the same issues as your foundation – expansive soil that may cause damage and puncture the downspout.  

Without the proper backfill, you could face flooding in your yard, so this step is important. When you work with Groundworks, the trench is refilled with rock and gravel which don’t expand when exposed to water. 

4. Replace Grass and Landscaping 

Any reputable company should replace any grass and landscaping that may have been removed during the installation process. Groundworks ensures your yard is cleaned and back to normal once the job is done.  

That way, the underground downspout becomes virtually invisible after installation. Once this step is completed, your home will have a more effective water management system. 

Call Groundworks for a Free Estimate!  

Underground Downspouts FAQs

Underground downspouts come in a variety of materials. These include PVC pipes, corrugated pipes, concrete pipes, and polyethylene pipes.   

For residential purposes, PVC is the most popular choice followed by corrugated pipes.  

It generally takes about 1 hour to install a single underground downspout. That could change depending on the length of the downspout.  

Either way, installing multiple downspout extensions on your property normally won’t take any longer than two days.  

Underground downspouts should be checked at least once a year. Sometimes, extensions can become clogged or worn down over time. 

If you work with Groundworks, we offer an annual service plan to check for these issues and make sure the system is still working smoothly.  

Service Areas  

Groundworks serves local communities in 33 states, including Colorado where bentonite clay tends to cause a lot of foundation damage. In Colorado, look for Groundworks in the following areas:  

  • Denver  
  • Boulder  
  • Fort Collins  
  • Littleton  
  • Colorado Springs  

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