How to Install French Drains

A French drain is a shallow trench filled with earth or stone or a perforated drain, which redirects contaminated groundwater to a downspout or down the sewer system. This type of drain is very effective in eliminating standing water in basements. French Drain is usually installed by using a specially-designed French drain pump or French drain line. The pumps used in French drains are generally pressure-washer systems. However, you can also install the French drains using hand power or a manual excavating machine.

French drain

There are three steps in installing the French drains. First, you have to determine where you want to install the French drain, then excavating the desired distance from the walls and pour the soil or gravel to the new location. Finally, you install the drain perforations straight down the slope.

First, determine the location you want to install the French drain in your yard. Measure the depth of at least three feet to the nearest house. After measuring, note the measurement to the nearest wall. Then, if necessary, hire a professional installer to help you install the French drain in your yard.

The next step in French drain installation is to excavate the desired distance from the wall. Note the measurement from the house to the nearest wall and adjust to get the depth of the trench needed. Then, build the trench according to the specifications given by your local authorities. If you don’t have the required expertise, ask for help from a contractor to make it. If your landscape fabric is not strong enough, consider using a wood ledger board, which will be stronger than your landscape fabric and will more likely withstand frequent leakings.

After digging the French drain trench:

  1. Prepare the foundation for the installation.
  2. Start by placing gravel in the bottom of the trench to prepare the foundation for further filling.
  3. Lay sand at an angle, with the slope towards the house to prevent water from stagnating.
  4. Remove all debris from the hole, including soil, tree roots, and any other solid material like bricks, impeding water flow from the basement.
  5. Remove any grass and sod from the area to prevent muddy spots from accumulating on the floor of the French drain trench.

When the hole is dug, fill it with dirt or soil according to the instructions of your local government. Then, level the area again and place the French drain properly inside it. Note that installing the French drains is more accessible when the ground is flat; if the ground slopes toward the house, you might need to use a pump to keep the French drain entrance open. It’s always best to practice before actually installing a French drain to make sure everything is correct.

Finally, if you’re doing the project yourself, dig the trench once, using the excavating tool (a large trowel) to level the area and position it. Then, use the pump to keep the French drain open. When digging, make sure the dirt is firm; otherwise, the French drains will not be installed properly.

After digging the French drain:

  1. Set the pipe into place.
  2. Please make sure the French drain exit is above the slope, as it exits the ditch, and it needs to be in an upright position.
  3. Line it up with the house.

If you have a hill, you might need to install a wooden board on the uphill side of the French drain pipe to keep it from slipping away when the water comes. Lastly, screw on a dirt timer into the pipe near the top of the French drain to let the soil slowly drain away from the French drain.