Arid Basement Waterproofing HAS BEEN Serving New Jersey and New York Since 1963

French Drain Installation

A properly designed and installed French drain system is the only complete and permanent solution to ground water intrusions in your basement.

Water always flows downhill, and by the easiest route possible. That's the basic concept behind a French drain; a slightly sloped trench filled with gravel and perforated pipe that's used to divert underground water and relieve hydrostatic pressure to prevent flooding in your basement.

To accomplish this, we begin by opening a 12" - 14" trench in the basement floor (Fig. 1). Typically the trench will be along the perimeter of the basement. However, the length and location of the trench varies depending on the unique circumstances on site.

A perforated PVC pipe (Fig. 2) is laid in the trench and covered with gravel. The PVC pipe will catch any water that comes up from under the foundation or down through the gravel. The trench is pitched so that the pipe will quickly vent any water to a sump (pit) where it is discharged from the house by a pump (Fig. 3).

Once in place the pipe and gravel are covered back up with cement to blend in with the existing floor. In most cases we leave a 1"gap where the floor and wall meet (Fig. 4). This opening allows any water that might come off the wall to bypass the floor and trickle into the French drain. That water filters through the gravel and is evacuated with the rest of the ground water. Depending on the construction of your finished basement walls, in many cases the 1" gap will not even be visible.

A French drain is the only way to truly stop groundwater seepage in your basement. The French drain was designed to do more than a sump pump, which only relieves the hydrostatic pressure in roughly a 5-foot circumference and simply expels water from your house after it has entered. The French drain addresses the core problem by relieving hydrostatic pressure below your entire house or wall(s) before the water enters your basement. It is the only way to completely and permanently stop ground water from flooding your basement and damaging your foundation.


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French Drain

French Drain

Pressure Relief

Pressure Relief

Fig. 1

Fig. 1

Then we lay in a perforated PVC pipe to direct water to the sump.

Fig. 2

This is the pump that sits in the sump and expels the water from your house before it causes any problems.

Fig. 3

A 1 inch gap prevents water that may seep through the wall to end up on your floor.

Fig. 4