Divert Water with a French Drain: When do you need them
You may need a French drain if you have water pooling in your yard after a rain or a soggy yard that never seems to dry. A French drain will help divert water away from your foundation and your yard. Here’s how they work:
Water always flows downhill, and by the easiest route possible. That is the basic concept behind a French drain, a slightly sloped trench filled with washed gravel and a pipe that diverts water away from your house.
French drains provide an easy channel for water to flow through. Water runs into a gravel-filled trench, then into perforated pipe at the bottom of the trench. Essentially, a French drain is used to divert water to another location.
Water travels freely through the pipe, which empties a safe distance from the house.
The trench bottom should be sloped about 1/8 inches for every foot in the direction you want water to flow. Depending on your situation, the water can be diverted to:
- A low-lying area of your property
- A drainage ditch
- A dry creek bed
- The street
Things we do to extend the life of your French drain.
We line the channel/trench with filter cloth. Then the bottom of the filter cloth will be filled with 2-3 inches of washed pea gravel. A 4 inch perforated corrugated pipe with a filter sock on it will be laid in the channel. The rest of the channel will be filled with washed pea gravel and the filter cloth lining the channel will be folded over on top of it and pinned down with sod staples.
Please keep in mind.
In severely heavy rains/storms or flash flooding a French drain will not prevent water from flooding or pooling. Movement of water is limited to the size of the drain. After a period of time it will divert the water but it will not do it instantly. Have to think of it like pulling the plug from a drain with the bathtub completely full. The water takes time to drain.
Keep your French drain clean
Even though we use filter cloth and gravel it is very important to keep the French drain clean. Silt, mud and leaves can clog a drain. This then would require it being dug up and redone.