How deep should a French drain trench be?
French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.
Does French drain need an outlet?
A properly designed French drain system does not require an outlet. The water will simply soak into the soil as it flows along the perforated pipe. In fact, a French drain doesn’t require an inlet on just one end either. You can construct the drain to accept water along its length, and disperse it underground.
What size gravel should I use for a French drain?
Use Natural 1-1/2″ round rock for best drainage. Washed rock is ideal. Avoid small pea gravel as the spaces in between stone is smaller minimizing flow rates. Avoid Crushed Rock (minus) that compacts and has “fines” that will clog pipe inlets.
Should I use landscape fabric in French drain?
Non-woven geotextile fabric is the best choice for drainage applications where water flow through (permeability) is the main concern. Non-woven landscape fabric is commonly used in French-drains, drain-fields, and erosion control.
Do french drains need an exit?
Short answer to the title of “Where should french drain terminate?” is that, ideally, the french drain will terminate to an above-ground exit on the side of a hill or at least a downwards slope, so that the water that was in the drain can escape to get into the place that normal surface runoff goes from the property.
How deep should you make a French drain?
Does French drain need a fall?
Properly constructed, french drains will work well to transmit water from the pipe to the exit of the pipe; however, they are not very efficient in dewatering poorly drained soils. Adequate fall means at least 2 ft lower per 100 ft of pipe or 0.25 in. per foot of slope.