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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.
How shallow can a French drain be?
DIGGING A TRENCH FOR A FRENCH DRAIN Because there is a direct relationship between the diameter of a drain pipe and its relative effectiveness, make your trench no smaller than 12 inches wide, and aim for a depth between 18 and 24 inches.
How wide and deep does a French drain need to 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 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.
How close to the house should a French drain be?
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 50 foot 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.
What is the difference between a French drain and a trench drain?
Aside from what we’ve listed here, the difference between a French drain and a trench drain is that a French drain is used for water that is underground while a trench drain diverts excess water from a surface.
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.
Where do French drains run to?
As mentioned a moment ago, French drains ensure any rainwater in outside your property will flow away from the building. The liquid runs into a gravel trench and then flows into a pipe at the bottom of the drain. The water travels through the tube and then empties somewhere safe away from the house.
What size gravel is best for French drain?
In general, you want to aim for ½ inch to 1-inch gravel for drainage. Areas that will see especially heavy flow may need larger gravel. Or, projects without drainage pipes may also need larger gravel. For example, a French drain without perforated pipe needs 1 ½ inch gravel.
How much water can a French drain handle?
Generally, a French drain should drop at least one percent in depth for every 100 feet of length.
Is sand or gravel better for drainage?
Gravel is far better at providing drainage than sand. Sand grains will interlock and form a barrier that prevents drainage. If you level a driveway or path with sand, leave several inches so you can add base gravel on top of the sand.
How long will a French drain last?
Properly installed drains use advanced plastic sheeting called geotextile to protect the drainpipe from a blockage. French drains can last decades before needing maintenance. If your home requires a sump pump, a high-quality model will last around ten years before needing replacement.
How often replace French drain?
This is why most experts state that a French drain is not a long-term solution to a drainage problem: You have to dig it up and reinstall it every eight to 10 years.
Should French drain be next to foundation?
It’s important to install French drains around foundations because a French drain can prevent water from causing foundation damage.
How much do french drains cost?
According to Fixr, the average French drain costs $4,500. An exterior drain located fairly close to the surface could cost as little as $1,000, or $25 per linear foot on average. Drains installed under your basement floor could cost $2,000 or more. Expect to pay $60 to $70 per linear foot for installation.
Is a French drain a good idea?
French drain systems are incredibly effective because, unlike typical surface drains, they collect water over the entire length of the drain as opposed to one dedicated area. The force of gravity helps to guide water along a reliably smooth path to a desired discharge point.
Is gravel necessary for French drain?
Good drainage is important to ensure that a home stays dry and free of mold. 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.
How much area will a French drain cover?
Generally, a French drain should drop at least one percent in depth for every 100 feet of length.
Do you cap the end of a French drain?
Cap the end at beginning of the system. Level rock 4 inches from the top of the trench. Note: If you just dump rock on top of the pipe, it will shift to one side of the trench. Make sure to keep it in the middle of the trench.
What is the difference between a curtain drain and a French drain?
A curtain drain is an underground trench that slopes downward. It usually begins around two feet below ground level and is one and a half feet wide. A French drain sits at ground-level. You can see the gravel even with the ground around it.