French Drains and Foundation Drains
Sometimes we have to live with a neighbor’s landscape. If you are below a neighbor’s yard, then you will be getting double the amount of rainwater.
One of the best ways to divert water is by a French drain (see Figure 3.4). A French drain traditionally is a trench with gravel in it to catch water and channel it away from your home.
Figure 3.4 A French drain catches water and channels it away from your home.
Find a place on your property at the bottom of the slope where you can horizontally catch the water and safely divert it away from your home. You don’t want to spill water into another neighbor’s home.
You should dig a French drain 8"–12" deep and 6" wide. You fill the trench with landscape fabric, pour in gravel, and wrap the gravel with the fabric creating a tube to keep out the dirt. Then shovel in some coarse sand and finish it off with sod.
Foundation drains are installed at the bottom of the foundation to divert the water that gathers around the house (see Figure 3.5). These drains are mandatory for some newer homes. The principle for the foundation drain and the French drain are the same; however, a foundation drain uses perforated PVC pipe that catches the water and diverts it around the house. Landscaping fabric is usually put on top of the PVC pipe, then gravel, then tarpaper or about 4" of straw before back filling. Make sure this is sloped properly so the water moves to a storm sewer or disposal area.
Figure 3.5 A foundation drain diverts water that gathers around the house.
For more information about French and foundation drains, see Chapter 6, "Drainage."