A French drain is a narrow trench filled with earth or stone or containing a perforated drain for seeping off surface water and/or groundwater away from a place. The depth may vary depending on the purpose and design of the French drain, but they are usually as deep as four feet. For a typical French drain, the trench is lined with a layer of soil that has been packed around it, leaving a two to three foot wide by two to three foot long depression in the ground.

After the trench is dug, a layer of soil is poured over the trench and left to set. A sloping site is then lined with a layer of soil. If the French drain pipe is going down, then the slope will need to be steeper, whereas if it is going up, a thinner layer of soil can be used. Once the soil has been placed, a PVC pipe or flex pipe is inserted into the depression, and then concrete is poured over the concrete to seal it. Then a waterproof mixture is applied to the pipe, and it is held in place with a steel strainer.

An alternative to the French drain is to use a French drain excavator. This is more costly than a French drain, but can be more effective. A French excavator is an excavating machine that has a wide-mouth digging ability, and is generally powered by a engine. These machines can dig a wide hole, but like a French drain, the slope needs to be steeper to maintain the drainage.

In order to dig a French drain, you first need to have a qualified person on hand to make sure the trench is level. By using a professional grade French drain kit, there should be no problem with this. Once the level is established, the French drain excavator is turned on, and a large amount of gravel is poured through the opening. This gravel acts as a filter to catch runoff water, which helps to reduce pollution and prevent flooding.

As the gravel is poured, it is covered with a filter fabric, and then topped with a layer of soil. The French drain installation then begins. The soil helps to contain the gravel and create a firm base for the French drain pipe system to rest on. A series of drainage pipes, each laid from a different direction, are then placed through the fabric layer and connected.

For larger jobs, such as sewers and drainage pipe systems, it is recommended that you hire a professional company. For French drains, you can install your own French drain system, if you are careful enough to install them properly the first time. However, installing French drains right yourself may not be the best idea. Installing French drains without the proper preparation may result in a leak, and then you would have an entire section of exposed French drains with water collecting on the surface.

Before beginning to install the French drains themselves, you should create a channel for them to run under. This channel should be about two feet wide and four feet long, allowing for the length of the French drain pipes to cross. Since most gravel is not large enough to be installed along the surface, you will need to install the gravel inside an existing trench filled with soil. With enough rainfall, the gravel will catch enough water away from the French drain so that it will no longer be visible.

After creating a channel for the French drain to go through, you will want to line it with landscape stone. You should put landscape stone on the inside channel, and on the outside edge, you should line it with sand. This ensures that the water will spread evenly throughout the French drain pipe. When the gravel becomes saturated, it will cut off the flow of water, but when the soil around the French drain has dried out, then you can remove the landscape stone and fill in the channel with dirt.