French Drains – A Practical Solution for Water Management

Sept. 8, 2010 - PRLog -- Introduction

A French Drain is an underground water management and drainage system developed and popularized by Henry French, a Concord, Massachusetts judge and farmer, and discussed in his 1859 book, Farm Drainage. Though his actual drainage system predates him by several centuries (the ancient Romans utilized a version), the French drain continues to be one of the most efficient and widely used methods of redirecting water today.

The French Drain’s Humble Beginnings

Henry French’s original idea came to him through careful observation. His findings – water runs downhill and loves to accumulate in the most inconvenient locations. Henry observed water behavior and the laws of nature until he figured out the best way to make sure it would run in the direction he wanted. His system was developed around the already existing idea of a ditch/trench or gutter/pipe system of drainage. But this system could easily become clogged, requiring constant and costly maintenance. Instead, he utilized gravel as a screening element to minimize clogging over time and would allow water to flow freely according to the laws of gravity.  Though it has undergone many improvements over the intervening years, it continues to be one of the most efficient and widely used methods of redirecting water.

Today’s French Drain System

Generally a French drain is used today to protect the foundation of a house or other structure from ground or surface water. Good drainage is important to ensure that a home, particularly a basement, stays dry and free of mold. Wet basements and the associated groundwater accumulation are the primary causes of financial, structural integrity and health-related problems for today’s homeowners.

Exterior French drains usually consist of a trench, often lined with landscaping textiles that prevent clogging from dirt or roots, as well as reducing the possibility of the drainage material from migrating , one or two perforated pipes surrounded by gravel, (depending upon sizing and redundancy requirements and always placed perforated side down), and covered with sand for further filtration of sediment. The advantages of an exterior French drainage system are it’s relatively low cost and easy installation, generally low maintenance (a French drain can last up to ten years without maintenance), and the fact that it can be covered inconspicuously with turf to maintain the aesthetic beauty of the landscape.

In addition to their primary function of directing water away from your home, French drains are also environmentally proactive as they can lead to a dry well, a structure that returns excess water to the supply of groundwater, or to a rain garden, an environmentally friendly invention that uses wetland plants to absorb excess water and return it to the atmosphere through transpiration.

Four Common Uses of French Drains

In waterproofing your home and/or property, four common uses of French drains are the following:

1.   a shallow curtain drain to divert surface water;
2.   a deep French drain to keep water out of the basement;
3.   an interior French drain to stop water where it enters the home;
4.   a French drain built into a retaining wall to eliminate pressure build-up on the wall.

A shallow curtain drain can be used to eliminate problem areas on your property where water build-up can occur, such as a low spot on the lawn or a continually washed out landscaped bed. It can also be used to divert water around your house. This fairly shallow drain extends horizontally across your property, uphill of the area you want to dry out and redirects the water to either side.

A deep French drain runs around the perimeter of the house at the footing level. Though this is easy to install during house construction, it is much more problematic and costly to install later. Sometimes on a flat property, collected water may need to be piped to a basin at a low point in the basement where a sump pump can remove it from the home. For information on capabilities and quality of sump pumps, consult a waterproofing professional.

An interior French drain should be used if you cannot keep water from seeping into your basement, since it can involve some extensive work within your living space. Generally, a channel is cut around the perimeter of the basement floor. Perforated pipe is laid all the way around. The perforated pipe and stone field then directs the water to a collection tank sunk into the floor and a sump pump carries it out to the yard or a storm drain. The channel is patched with a thin layer of concrete, except for a small gap at the edge to catch any water that comes down the wall. Again, discuss sump pump capabilities with a waterproofing professional.

And, of course, any retaining wall that is built into a hillside should incorporate a French drain so that the wall footings don’t give out from the water pressure that can easily build up behind the wall on the downslope.

Consult A Waterproofing Professional

For any home waterproofing problems, consider consulting with a reliable waterproofing specialist regarding the use of a French drain. They can properly inform you about your specific needs.

Visit us online at: http://www.vulcanwaterproofing.com/

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