French Drain Installation

Those new to the concept of landscape drainage will find the following paragraphs on french drain installation helpful. Above all others, this drainage system is the most commonly used landscape drainage system, especially in the Houston area. We discuss not only the necessary steps of a french drain installation primarily but also provide interesting and useful facts. Houston Landscape Pros will help you determine if you need a french drain or a catch basin drain system

In addition, we can assist you in your lawn sprinkler system or landscaping needs. Keep in mind that we are Texas licensed irrigators and landscapers, and we can inspect your underground watering system instantly. Call us at 713-396-3320 or fill out one of our free quote pages!

French Drains in Houston

The difference between the French drain invented by Henry F. French and the modern French drains is the use of PVC pipes. Nowadays, there are two types of French drain systems.  They differ slightly due to their placement. Here we will introduce the two French drain types:

For some French drains in Houston, depending on the situation, the drain pipe is buried with gravel closer to the building itself. This type of drainage pertains to both residential homes or commercial buildings. Due to it’s construction and proximity to the building, only gravel will cover the drain. Professionals implement this type of french drain when the problem area receiving excess water is close to the building and poses a threat to the foundation.

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Modern Backyard French Drain Installation type 1.

By contrast, the second type of French drain system can be under any turf, including Artificial Grass, and for any problem area. The ability to install a lawn or a landscape bed over the French drain is the major difference between the two types. That is to say, the first type can never have dirt or grass covering it. For example, say you had a flooding issue in the middle of your yard, but you do not want to see a catch basin grate. In this case, the second french drain model would be perfect for this situation. It is the ideal solution because it will be hidden entirely from view. Although this type of french drain will be more expensive, it is versatile.

The following will outline the French drain installation process for the two models.

How does a French Drainage System work

When it rains, water will drain to the bottom of the trench. We put gravel in so that water can go straight to the bottom and into the pipes. Professionals fill the trench with gravel instead of dirt for two reasons. Firstly, it prevents the water from flowing to the bottom. Secondly, it also clogs the pipes. When the water goes to the bottom, it will start to fill the trench and rise until it enters the pipes through the perforations. Next, the perforated PVC pipes will divert water into the solid pipes that will take it to its final destination. Since the French drain system is always at a downward slope, the water will follow the slope and run off into the proper area.

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French Drain Pipes and Materials

Before beginning the french drain installation process, the installer must have the proper materials. Houston landscape Pros always chooses the indicated materials that are compliant with city codes. Undoubtedly, for a French drain pipe, the best is PVC SDR-35 piping to use. In comparison to most pipes used in this kind of drainage it is a little more expensive. However, we have found it to be the most durable product. It protects against root systems and movements in the soil. A French drain pipe requires 4-in PVC perforated pipes and solid 4-inch PVC pipes.

Additionally, we use geotextile fabric to prevent dirt from coming into the pipes. After that comes the gravel. In this case, we recommend the most natural gravel available for french drain installations, which is River Rock and Bull Rock. Another essential material is bend-a-board edging. It is durable and made out of recycled material. Lastly, don’t forget the shovel needed to dig the trench! The shovel will be your best friend for the trenching part.

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French Drain: Type 1

Below Houston Landscape Pros will teach you the necessary steps. If you have any more question after reading the information provided below, then go to our landscape drainage web-form. One of our professional team members would be happy to answer any questions or visit with you on site.

There are roughly four parts to a French drain installation type 1:

1. Digging the trench, laying the geotextile
2. Laying the perforated PVC pipe correctly
3. Covering the pipe with gravel on all sides
4. Inserting the edging

First Step:

Digging the trench is the most labor-intensive part of the process. The trenches require manual digging because the installer must be mindful of utility lines. The beginning of the trench will be approximately six inches deep. Then, the installer must dig the trench at a slope: one inch deeper for every ten feet of piping to force the water to its final destination. Sloping the trench in this way accounts for friction loss and flow velocities caused by the moving water.

french drain installation type 1 diagram Houston Landscape Pros

French Drain: Type 1 Diagram

Second Step:

The next step is to cover the trench completely with a landscaping geo-textile fabric. This unique material keeps the perforated PVC pipe clean from debris that could potentially clog the system. After that, lay down the PVC pipe with the holes facing down. Then, cover the pipe with gravel on all sides. After the job is over, you will be able to see only the gravel at the same level as the ground.

Third Step:

The final step of the French drain installation is the edging. It will be the barrier between the gravel and the grass or the gravel and the landscaping bed. Otherwise, the grass will try to grow over the French drain, which does not look good. Again, only install the French drain in the problem area. Eventually, the French drain connects to a pipe that is completely solid with no perforations that will take the water to its deposit area. Dirt will cover the solid pipes with no holes. Lastly, grass will be laid on top of it since these pipes cut straight through the grass area of the lawn.

French Drain: Type 2

As previously stated, the difference between type one and type two of the French drain is that type two can be installed under any turf. It will use all the same materials with a few differences in the installation process.

The six steps for the French Drain installation under any turf:

1. Dig the trench
2. Lay the geotextile
3. Connect the perforated pipe with the solid pipes
4. Put in the gravel
5. Wrap both the gravel and the perforated PVC pipes
completely with the geotextile material
6. Cover it with dirt and the preferred turf

French Drain Type 2 Diagram Houston Landscape Pros

French Drain: Type 2 Diagram

French Drain Under Existing Grass Installation

Since installed under a grass turf, the trenches will be much deeper. The channel needs to be about 1 foot deep at the start to install grass on top. The gravel and the pipes will each take up 4 inches. The lawn will need the remaining 4 inches of soil to grow correctly. Then, the trench will slope 1 inch for every 10 feet of piping. This one will be more expensive because of the labor involved in digging deeper trenches. It will also be more costly because there will be a lot more dirt that needs to be hauled out and stored somewhere until the trenches are fully dug and the piping completely installed.

Geotextile Installation

Next, the geotextile material will be laid on the trench, making sure to put enough down to be able to cover the gravel and the pipes completely. Then, the perforated pipes will connect with the solid pipes that will take the excess water to the exit area. Since soil and sod will be installed on top of the French drain, the gravel along with the perforated PVC pipe must be completely wrapped around with the geo-textile material. This fabric-like material protects the landscape drainage system from debris. Lastly, the soil and the grass will lie on top.

French Drain Additional Information

French drains cannot be connected directly to any other type of landscape drainage system; there needs to be at least 5 feet of solid piping separating it from another landscape drainage system, such as a Catch Basin or a Sump Pump Drainage System. Putting one any closer would effect the opposite of the French drain’s purpose. A French drain cannot be connected to another landscape drainage system on the higher side of the slope because a French drain cannot have more water flow into it from another system. The design aims to deal with specific problem areas. Having another system higher on the slope of the trench will cause the French drain to overflow or even clog.

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French drain installation and catch basin system side-by-side but separate lines.

French Drain Cost

A French drain costs anywhere from $1600 to $4500. The French drain installation cost will vary depending on the following factors. The French drain installation cost will vary depending on the following factors: pool equipment, utility lines, lawn sprinkler systems, trees and shrubbery, and fences. These factors impact prices because they will be time-consuming obstacles. The most expensive element of a French drain installation is labor. Remember, the more time consuming the work, the higher the price of the job will be. When our landscape drainage specialist provides an estimate for a customer, he must inspect the property for obstacles during the installation. However, the proposed price for the French drain installation enumerates the labor-intensive obstacles. The size of the property is also a factor. A larger property will require more piping; therefore, this property will involve more labor to dig longer trenches.

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