How deep do you have to dig for a French drain?

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.

What is the minimum depth for a French drain?

Depth Recommendations

The minimum depth is typically ​18 to 24 inches​. This depth helps capture most of the water that's an issue. If your goal is to protect your foundation or keep water from getting into the basement, you want your pipe installed deep enough to achieve that goal.

How shallow can a French drain be?

The trench should be about 18 inches deep and 9 to 12 inches wide. French drains need to have a slope of at least 1 percent, so the force of gravity will work for you. This means that the drain should slope down a total of at least one inch for every 10 feet of pipe.

Does a 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.

How deep should a drainage trench be?

A drainage trench should be at least 18 inches deep. This allows you to install a gravel bed, as well as an adequately-sized pipe to carry away water.

How Deep

How far should a French drain be from the house?

How Close Should a French Drain be to the House? A good rule of thumb is to install french drains 3 feet from the house. Make sure to measure around the porch, patio and deck.

How much gravel do I need for a 100 foot French drain?

To calculate gravel needed for a 100′ french drain, multiply the length of the trench by the width and depth. If you plan to lay down 4 inches of gravel, multiply 100 feet x 4 inches = 400 cubic feet. Since each bag equals 1.5 cubic feet, divide 400 by 16 to determine the number of bags you will need about 26 bags.

Can I cover a French drain with dirt?

Can I cover a French drain with dirt? Because a French drain has holes throughout the pipe which allow it collect water, you should not install dirt on top of the drain pipe. Installing dirt will clog the pipe and the holes, rendering it useless.

What size gravel is best for 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.

What is better than a French drain?

A sump pump is one the the most popular and most effective alternatives to a french drain. A sump pump add lots of drainage but comes with a few downsides. A sump system requires electricity to function and can be expensive to install and maintain.

Do you have to use gravel in a French drain?

The old way of installing French drains is to do it without the gravel and the fabric. Without the gravel and the fabric, however, the drain can clog up with sand and soil over time.

Can a French drain be too deep?

Gas and water lines, electrical wires, and sewer pipes are some of the things that this digging may encounter. If the drain is dug below the footer, it will cause the home to settle and it's important not to dig too deep.

How much does it cost to put in a French drain?

Location in Home and Accessibility

Interior French drains are more expensive to install than exterior drains because they require more labor to excavate through a concrete floor. On average, homeowners can expect to pay between $5,000 and $13,500 to have a French drain installed in the home.

What goes on the end of a French drain?

The two ends of a French drain system are: The drain field, or high end, where excess ground water enters the drain pipes. The drain exit, or lowest point, where water leaves the system.

Which is better sump pump or French drain?

Sump pumps offer a few key advantages over french drains. The biggest and most obvious advantage is the amount of water they can pump and drain. Pumps like the Zoeller M53 Mighty Mate can drain up to 43 gallons of water per hour at a 5′ head height – something that french drains can't compete with!

Should a French drain have standing water?

Look for Standing Water

French drains are designed to collect rainwater and channel it downhill. If surface water is standing in low areas of the yard that are supposed to flow into your French drain, you have a drainage problem.

Can you run downspouts into French drain?

A French drain is actually a network of pipes laid in trenches dug beneath the ground through which water runoff can flow. This structure can be attached to your downspouts and will work seamlessly with your existing gutters.

How much river rock do I need for French drain?

How much gravel do I need per foot of French drain? You would need around 0.72 cubic feet of gravel per foot length of French drain for a typical French drain width of 10 inches and a depth of 12 inches if you're using a 4" drain pipe.

Can you use landscape fabric for 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.