French drains are often installed around a home foundation in two different ways, or in combination of both:
* Buried around the external side of the foundation wall
* Installed underneath the basement floor on the inside perimeter of the basement
In most homes, an external French drain or drain tile is installed around the foundation walls before the foundation soil is backfilled. It is laid on the bottom of the excavated area, and a layer of stone is laid on top.  In many cases, a filter fabric is then laid on top of the stone to keep fine sediments and particles from entering. Once the drain is installed, the area is backfilled, and the system is left alone until it clogs.