DIY Simple Drainage Around a Foundation

French drains can be installed around a foundation or in other trouble areas.

A poorly-draining landscape around a house or other structure can lead to a number of problems ranging from annoying puddles in the lawn or landscape beds to serious structural problems or a flooded basement. One possible solution to a home landscape's drainage woes is the installation of a French drain. This type of drainage system incorporates a perforated pipe covered with gravel and filter fabric buried at the bottom of a trench that can be dug as deeply as the footing, if needed. It can be placed around the entire foundation, only in problem areas or to catch water that runs down a slope towards a foundation.

Things You'll Need

• Shovel and other digging tools
• Level
• 4-inch perforated PVC pipe
• Gravel or river rocks
• Landscape cloth or filter fabric
• Backfill material

Instructions

1. Dig a trench where the French drain will be installed. The trench can be as narrow as 8 inches or wider than 2 feet and as deep as needed to address the drainage issue. If the drainage is primarily a surface issue caused by roof runoff or a gutter downspout, the French drain may not need to be any more than 2 feet deep. If the drainage issue extends deeper, make the trench for the French drain deeper than the bottom of the foundation.

2. Level the bottom of the trench. The trench and pipe should have a slope of less than 2 percent, allowing for a slow flow towards an outlet if the system will be draining to a ditch, pond or other feature.

3. Lay the perforated PVC piping in the center of the trench bottom. Check to make sure that the slope of the piping reflects the slope of the trench bottom and adjust it by moving soil around as necessary.

4. Place at least 12 inches of river rock or large gravel around and on top of the PVC piping. Use large, clean gravel or rocks so that water can flow through freely without collecting silt that can clog the piping. The gravel layer can extend as high up as 6 inches below the ground surface.

5. Cover the gravel layer with landscape cloth or filter fabric that will let water pass through but prevent solids from entering the gravel bed or piping.

6. Backfill the trench as desired. Fill it in with soil and revegetate using only plants that have a shallow root system or fill it to the surface with gravel or large rocks.

Tips & Warnings

• If desired, the perforated piping and the entire trench can be wrapped in or lined with filter fabric. Thorough protection from silt may extend the functional life of the drain or reduce the need for cleaning.

• Consult local utilities before digging to determine the location of any buried utilities.

References

• North Dakota State University Extension Service; Drainage Around the Home Can Prevent Wet Basements; Ken Hellevang, et al.; June 2005
• Washington State Unviersity Clark County Extension; Improving Drainage; Erin Harwood; September 2005
• "Foundations and Concrete Work"; Fine Homebuilding; 2003
• "Dig This!: Landscaping Without a Backhoe Or a Big Budget..."; Kate Anchordoguy; 2003
• Foundation Repair Association; Foundation Maintenance; W. Tom Witherspoon