French drains   
French drains usually are designed and installed with a slight slope to carry the water down to its destination. Perforated pipe is laid in a trench and covered with sand or gravel. The rock gravel used is usually three quarter inch to one and one half inches in diameter to provide good drainage and a firm support. Water flows into the pipe through the filtering sand or gravel. The actual drain includes pipe couplings and anchors. The couplings connect pieces of pipe in a continuous length. Most important is that they do this without leaking. The way to ensure good fittings is to select coupling designed for the pipe in use and to use watertight gaskets with the couplings.  

Another important fixture in a French drainage system is the anchor. Pipe anchors are built on slopes to keep pipes in place. This entire assemblage of perforated pipes, coupling, anchors, gravel, and geothermal textile can only work well together if the planned design and installation for the given area have been thought through carefully. If a homeowner plans a do-it-yourself project, it is suggested that they first consult manuals and landscape professionals on how to install a French drain.
 
French Drain Installation
Before installing a French drain around a basement wall, it is advisable to investigate their functioning and maintenance. Although a French drain that is built around the outside perimeter of a building can work well for a number of years, it more likely will become clogged and cause flooding at some point. When that happens, the walkways, shrubberies and gardens must be torn up for drain repair. This is an expensive undertaking which possibly can be avoided with some earlier consideration and planning.

French drain installation on the inside perimeter of a basement is most often done to relieve a wet basement. The first task is to remove the floor and cement directly around the inside of the outside walls. Then stone or gravel is put down as bedding, and the drain is laid on top of it. Water entering the basement at the juncture of the wall and floor is collected in the drain and then pumped out of the house by a sump pump.

The advantage of an interior French drain over the exterior version is that the former is much less likely to clog. It is recognized that maintaining dry-basements can be challenging. For that reason, it may be easier, less time consuming and a better solution to hire a professional contractor for French drain installation.