How to Grow Grass Over a French Drain 01 Mar 2021

How to Grow Grass Over a French Drain

A soggy yard, standing water, or poor storm water drainage can prevent you from getting the landscape you want and enhancing the beauty of your exterior. Fortunately, a French drain may be the right solution to your problems. A French drain helps to direct ground and surface water away from over-saturated areas towards a lower point where it won’t cause any damage.

French drain services can help to improve your landscape in various ways, including:

  • Providing shallow drains to divert surface water
  • Preventing pressure build-up on a retaining wall
  • Preventing water from seeping through the foundation
  • Stopping water from entering your home or basement

It is a relatively low-cost system that’s easy to install and maintain, since it draws water into the drain through gravity to prevent pooling and diverts water appropriately. Additionally, a French drain can be covered to help you maintain the aesthetic of your landscape.

What is a French drain?

A French drain comprises a trench with a slope in the direction the water will drain, which contains a buried perforated pipe installed at a depth of 12-18 inches and covered with a gravel bed (perf side down). Professional plumbers dig a trench with a 1% slope or 1 inch deep per 8 feet in length. The trench usually has a minimum width of 12 inches, and a depth of 18 to 24 inches. The trench is then partially filled with a few inches of crushed stone, after which a water-permeable landscaping fabric is applied to prevent weed growth.

The next step is to lay a rigid PVC (polyvinyl chloride) pipe with predrilled holes, though they may also place a flexible drain pipe that’s cut with slits. Although the flexible pipe is cheaper and easier to work with, it’s not as easy to clean as PVC in the event of a clog. PVC is also more durable. The pipe holes are oriented downward, and the pipe wrapped in landscaping fabric to prevent dirt and roots from obstructing the system. The next step involves infilling the trench with gravel to the top or just a few inches below ground level to add topsoil.

Getting Started

The first step to getting a neat lawn above a French drain is getting the drain system professionally designed and installed. The areas that need a French drain usually have serious drainage caused by issues that range from flat land to poor architectural and landscape design to non-porous soils that retain too much water. High water tables and erecting buildings on low elevation that is exposed to off-site runoff can also cause drainage problems. Unless you have some skills in soil and water management, it’s unlikely that you will solve this kind problem satisfactorily without seeking expert help.

The process of setting up a French drain seems rather straightforward, as you need to dig a trench at a gradient, add some gravel, lay a pipe with holes, then cover it up to ground level. However, an incorrect design and installation can render the entire system worthless while wasting your time and money. On the other hand, a well-designed French drain system will not only keep your property free of excessive moisture and water, but also enhance the beauty of the landscape.

Some of the common issues associated with poorly designed French drains include:

  • A shallow trench that results in flooding
  • Wrong location of the drain
  • Pipes getting clogged by roots
  • A small pipe that starts overflowing

Any of these issues can frustrate your efforts in dealing with flooding or oversaturation, leaving your yard in a mess. So it’s important to get a professionally designed system by reputable French drain services who can get the job done right the first time. This will then allow you to successfully cultivate healthy grass on the French drain to beautify your lawn.

French Drain Designs that Favour Plant Growth

Besides improving drainage, you can use runoff from your French drain to do some landscape projects of your choice. While you can choose to leave the French drain open or the trench simply filled with gravel or coarse stone, some homeowners prefer to cover it up completely by adding a few inches of topsoil and sod for aesthetics. Once the French drain is covered, you have a three-dimensional watershed system that can be enhanced with plants.

Some designs to consider for French drains include:

1. Rain garden

It features a large but shallow bed positioned at the end of the French drain run. The trench is filled with gravel, but provides room to plant deep-rooted water plants. Since the plants have deep roots, they can easily access as much ground water as they need while the rest is drained via the French drain. This helps to reduce pollutants that wash into streams, ponds, lakes, and wetlands, while minimizing the strain on water treatment plants. Many plants that grow well along streams, including rose mallow, cardinal flower, and ferns, can thrive in your mini-watershed.

2. Dry well

This refers to a large hole in the ground that’s lined with landscaping fabric before being filled with gravel. The landscape fabric lining holds soil and silt from mixing with the gravel. Alternatively, some homeowners may request the installation of a perforated drain pipe (drain tile) in the well to slow down water dispersion. This makes it possible to create an area to collect and filter water down into the soil. A dry well is typically placed at the junction of multiple French drains. With the backfill soil that settles at the top, you can grow some grass.

3. Landscaping French drain

Grass doesn’t require as much water as streamside plants. So, you should use a French drain system that leaves only enough moisture for your grass. This type of French drain features a trench that’s filled with gravel and then lined with landscape fabric to hold the topsoil. Unlike a dry well that’s in the form of a deep well, your trench covers a wider area of your landscape, providing more surface area for topsoil to grow your grass.

When to Contact Professional French Drain Services

If your lawn feels squishy after it rains, then you should consider getting a French drain system. A properly installed French drain will not only be effective in improving drainage outside your home, but also make it easier for you to beautify your landscape with plants and grass, without the risk of clogging the underlying drain pipes. For more information, please contact Brothers Plumbing.

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