8 Common French Drain Mistakes and How to Avoid Them

Man digging out french drain in driveway to clean out

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If you want to install a French drain, there are a few things that you need to know.

A French drain sounds like a fancy device. However, it’s really just a gravel ditch with an embedded pipe for diverting water away from your home.

Gutters collect rainwater as it runs off your roof. However, a French drain directs water on the ground.

For example, you might notice a spot in your yard where puddles of water gather after a rainstorm. You’d use a French drain to resolve the issue.

French drains are also ideal for preventing water from seeping into your basement. Here, water might pool against your foundation and eventually seep into your basement. With a French drain, however, you can reroute that water elsewhere.

Keep reading for common French drain mistakes and how to avoid them.

1. Not Knowing Zoning Regulations

It’s important that your French drain doesn’t negatively impact anyone’s land or a public area. Either of these scenarios could lead to legal troubles. You’ll want to check with the local building authority for these reasons.

Building codes, community rules or zoning laws might restrict drainage projects in your area. Accordingly, it’s important to confirm your plans with any local building, zoning or homeowner’s authorities.

Also, you’ll want to call the “Call Before You Dig” hotline at 8-1-1 before you begin the project. The proper authorities will mark your property with paint or a flag so that you don’t accidentally dig into an underground utility line.

2. Overlooking the Direction of Water Flow

Here, you want to assess the flood-prone areas of your yard. You’ll need to determine a general direction for the flow of your French drain before you start planning. It’s important that water flows in the right direction—away from your home.

You’ll also want to think about the effects of exposed gravel in your yard. For example, you’ll need to think about how it affects vehicular travel. You may also consider how the gravel will affect the views and recreation areas in your yard.

3. Failing to Figure Out the Slope

A French drain needs a slope to work properly. The slope should descend at a rate of 1%. That rate is equivalent to a 1-foot drop for every 100 feet of French drain.

Alternatively, your property may have a natural slope that steeper, and that’s fine. However, it’s important to understand that a steeper slope creates more velocity.

Erosion can develop in the discharge area for this reason. You need to plan the slope of your French drain accordingly.

4. Not Lining the Trench

It’s also important to line your French drain with fabric. You want to use a continuous swath if possible.

If not, you can overlap pieces of fabric by at least 12”. However, it’s important to secure both ends of the fabric with staples driven into the ground. As you lay the fabric, fold the excess on both sides and trim it away later.

Also, it’s important to overlap the fabric in the desired direction of flow. In other words, the fabric on the high side of the trench must overlap the fabric on the low side.

5. Using the Wrong Gravel

The right drainage rock is vital for adequate permeability and drainage. Accordingly, you’ll want round natural stones for fill material.

This kind of stone will enable better flow through the material. Also, you don’t have to worry about pieces breaking off and clogging the French drain when you use the right rock.

Ideally, you should try to source 1 1/2” Round Rock. Washed Round Rock is ideal for a French drain.

6. Skipping the Drainpipe

Many homeowners fail to install a drainpipe in their French drain. Accordingly, their drain system cannot handle heavy water flow.

The idea of a French drain is to direct pooling surface water where you want it to go. However, this circumstance reduces the effectiveness of the French drain in mitigating idle water.

Most French drainpipes are perforated and 4” to 6” in diameter. These features give the pipe the capacity to move water away from structures and prevent pooling.

It’s better to include the drainpipe with the first go around. Eventually, you’ll realize that you have to dig the French drain up to install the pipe later, perhaps after a heavy storm.

7. Routing a Down Spout into the French Drain

Many homeowners also run gutter spouts directly into a French drain system. However, these kinds of systems can become overwhelmed with water during heavy rain. Ultimately, a flood of water will enter the drainage system.

Instead, you’ll want to install a catch basin before the drain field. Then, you can tie the French strain into the basin. As a bonus, the catch basin also provides you with a point of access to clean out leaves and debris that can clog your French drain.

8. Misdirecting the Pipe Holes

Some homeowners mistakenly point the holes in the pipe sideways. However, there’s a logic to this error.

They want the water to filter as far away from their house as possible. Accordingly, they’ll point the holes away from their home. However, that’s not how water works.

Instead, the holes of the pipe should face down. You want to keep the water level in the French drain as low as possible. The only way to achieve this effect is by pointing the pipe drain holes down.

The Importance of a Properly Installed French Drain

It’s important to install a French drainage system just right. Poor installation can lead to pooling in the drain system. In turn, the pooling can cause major issues and problems.

You’ll want to avoid the most common mistakes when installing French drain systems. For example, you always want to make sure the drain system is installed on a slope. This way, gravity will carry water out of the French drain.

Other homeowners make the mistake of installing a completely flat French drain. Resultantly, it takes more energy for water to move through the system. It cannot remove subsurface water properly for this reason.

Finally, it’s important to avoid low spots and dips in a French drain. These areas can create pooling.

Pooling is the problem that you’re trying to prevent in the first place by installing the French drain. What’s more, it can prove extremely problematic.

Moisture attracts the natural enemy of French drains—the dreaded tree root. Tree roots love standing water in your yard, even if it’s underground.

Once tree roots enter your French drain system, they’ll block the flow of water. This blockage will reduce the effectiveness of your French drain system.

Although it happens rarely, some homeowners even install a French drain with a negative slope. A negative slope will draw water back to your home. In this case, you might need a pump drainage system to remedy the issue until you can correct the error.

Why You Should Consider Professional Installation for Your French Drain

As you can see, many things can go wrong when installing a French drain. Also, these are only the most common French drain installation mistakes.

There are many more ways to foul a French drain installation. Accordingly, it might prove wise to hire an experienced professional for the job.

An incorrectly installed French drain can cause water to collect in your home. For example, it can lead to seasonal flooding in your basement.

It’s especially important to seek the help of a professional if the French drain will run close to your home. Here, the French drain could affect the natural runoff pattern of your property. If not executed perfectly, the drainage system can do more harm than good.

A Simple Device That's Not Always Simple to Install

In some instances, the installation of a French drain can present considerable challenges. It may call for the use of engineering skills and heavy equipment.

If you have a minor yard flooding issue, it’s quite possible that you can install a French drain system successfully. However, if you have major flooding or you need to keep water out of your basement, you’ll most likely need the services of a professional. Performing a French drain installation without the right experience and equipment can end up costing you more time and money.

Also, the landscaping involved in installing a French drain is typically harder than it looks. For example, most French drains need a ditch that’s about a foot wide and 18” deep. For every foot you dig, you’ll need to excavate one and a half cubic feet of soil.

Ten feet of soil weighs approximately 100 pounds. In other words, for every 10 feet of the trench that you dig, you’ll move about 1,500 pounds of soil.

You’ll also need to use more than half a yard of gravel for every 10 feet of drainage. Each yard of gravel can weigh between 2,400 and 2,900 pounds. In the end, you’ll most likely save time, money and grief by hiring a professional.

Avoid French Drain Mistakes: Call Us for Expert French Drain Installation

Now you know more about common French drain mistakes and how to avoid them. If you want the best contractor for installing your French drain, you’ve come to the right place.

Crawlspace Medic is an honest and dependable service. Our contractors are highly skilled in crawl space and basement repairs.

At Crawlspace Medic, we stand behind our work. Every job is warrantied. Furthermore, we’ll develop a customized long-term solution for your drainage, crawlspace or basement issues.

Contact Crawlspace Medic today at (866) 882-7295 or connect with us online for your crawl space or basement inspection, repair and maintenance needs.

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