Downspout Drains

Reversed Splash Block

Downspout Drainage and flooded Basements

Many homeowners are unaware of the risks that splash blocks pose to the foundation of their homes. They mistakenly believe that splash blocks are a suitable solution for managing roof drainage around their house. However, it’s important to understand the potential consequences before dismissing the importance of proper drainage.

Let’s be honest, downspout drains and splash blocks may not be the most exciting topic. However, their significance becomes evident when you experience a flooded basement or, even worse, encounter structural problems. You might wonder how a simple splash block can cause harm to the structure. I understand your curiosity, so let’s delve into some background information about the construction of your home’s foundation.

The Big Dig

To build a home, we have to dig! We dig to reach solid ground that will support the weight of the home. To ensure the safety of the workers and allow them room to work, we have to dig the hole a little wider, typically four or five feet wider, on all sides of the home. 

This area is known as the over-dig and is an OSHA safety requirement. When the foundation has been completed the over-dig area is filled in, this is called backfilling. Once the foundation is backfilled the area around the foundation is graded to drain water away from your home.

At this point everything looks great, but herein lies the problem. You now have an area of disturbed soil surrounding your home. This soil is not compacted to the same level as the undisturbed soil around the home and the looser soil will hold water, much like a moat around a castle. The difference is you can’t see this moat, so it goes unnoticed. 

Foundation Over Dig And Downspout Drainage
Home Constructed by Kelly in Bethesda Maryland

Don't Fill The Invisble Moat

Although splash blocks installed under your downspouts can help prevent localized erosion, they do not provide protection against basement flooding. Moreover, the excess water from the downspouts can accumulate in the loosely-compacted soil surrounding your home, essentially filling the moat with water.

This condition will cause the soil to settle, leading to an increased workload for your underground drainage system and sump pump. Over time, the excessive water can saturate and weaken the soil that supports your home, compromising its stability. It’s important to keep in mind that when your home was built, the foundation was placed on solid soil to ensure its structural integrity.

Solving The Drainage Problem

So how do we protect your home’s foundation?  Start by ditching the splash blocks and install downspout drains that channel water away from the foundation well past the over-dig area around your home, usually six to ten feet.

Downspout extensions can be a quick fix but are susceptible to damage by lawn maintenance equipment and they certainly lack curb appeal.

A better solution is to install an underground flexible corrugated drain pipe (pictured) or ridged plastic drain pipes. A good landscaper can handle this for you in a day or two.

Channeling water away from your home’s foundation is a big step to preserving the structural integrity of your home for years to come.


Buried Downspout Drain

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Picture of Kelly R. Regan

Kelly R. Regan

Kelly Regan, the founder of FullScale Home Inspection, has a deep-rooted passion for construction that began at a young age. Growing up, he helped his father build new homes and commercial buildings in Washington D.C. and Maryland suburbs.

Kelly is a certified Master Inspector with over 35 years of experience in residential and light commercial construction and remodeling. Kelly is also certified with the state of Maryland to teach home inspection and continuing education classes.

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