Table of Contents
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?
Add a Layer of Topsoil to Drainage Ditch Dig a trench along the outside of your footing. The trench should be at least 2 feet wide, and can be as deep as 6 feet for a basement or as shallow as two feet for a slab-on-grade home.
How far should a foundation be from a French drain?
We recommend installing the french drains between 2 and 5 feet away from the foundation. There are a few variables that impact the exact distance to dig the new drain lines to carry water away from your home. Finding the right distance: Check where water is pooling naturally during heavy rains.
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 much slope does a French drain need?
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.
How deep should drain pipes be buried?
Maintaining a depth of 12 to 18 inches is best for drain pipes, but the depth of the pipe may vary in order to maintain a downward slope, which is critical for proper drain functioning.
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.
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 should a French drain drain to?
LOCATION: French drains should run along the center of the low area(s) needing drained, and end at the desired drainage point. There should be adequate “fall” in the french drain construction, for water to naturally run downhill, toward the drainage end.
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.
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 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.
How deep should a perimeter drain be?
You’ll have to dig a trench around the perimeter of your footing. This trench must be at least two feet wide and six feet deep. For a slab-on-grade home, the trench can be as shallow as two feet.
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.
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 do I build drainage in my yard?
5 Yard Drainage Solutions You Can Do Yourself Reduce Your Watering Schedule. Extend Your Downspout. Dig a Creek Bed or Swale. Construct a Rain Garden. Install a French Drain and/or Dry Well.
Can you put a French drain next to foundation?
It can be placed inside a basement or outside along the foundation. If water pressure beneath the slab forces water into the basement via the joins of wall and floor or through cracks in the foundation, then a French Drain will be placed inside the basement along the wall and floor joins.
Can you use pea gravel in a French drain?
For a French drain without a perforated pipe, opt for even larger gravel, such as 1 1/2 inches across. Smaller gravel such as pea gravel would not allow sufficient water flow. No matter what the gravel or stone, opt for washed varieties, otherwise fine dust and particles may hinder or even stop water flow.
Can I use #57 gravel for French drain?
For large projects, such as a gravel driveway, pour a 3–4-inch deep layer of #3 gravel. Then, top it off with 2–3 inches of #57 gravel. You can use #57 gravel for paths and small runoff drains. For larger and more complex drains, such as a french drain, we recommend #3 crushed stone.
