Table of Contents
How deep should a French drain be dug?
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 deep and wide for a French drain?
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.
How do you build a French drain that lasts forever?
Can you make your own French drain pipe?
Installing a French Drain is fairly easy and you should be able to manage to build a drainage system like this with a few materials, and either a hired mini digger, or some serious hard work with a shovel and wheelbarrow.
Can a French drain be shallow?
A French drain is a good solution. This wide, shallow trench allows surface water drainage, yet is simple enough to install.
What size gravel do you use for a French drain?
Gravel used for this layer is typically 1/2 inch to 1 inch across — the larger it is, the better the water flow and less chance of clogs and blockages. For a French drain without a perforated pipe, opt for even larger gravel, such as 1 1/2 inches across.
How do you calculate the size of a French drain?
Measure the diameter of the drainage pipe. This is usually 4 inches. The volume of the pipe is expressed by the formula: volume = pi x (radius^2) x length of the pipe, where pi = 3.1415, and the radius is half the width of the pipe, expressed in feet.
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.
How deep should drain pipe 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.
How many years does 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 long do French drains last?
Generally speaking, a French drain will last approximately 30 to 40 years. However, the above-mentioned factors may shorten its life cycle and it must then be replaced by a team of foundation experts.
Why do French drains fail?
Over time, a French drain may become clogged. Tiny soil and clay granules slip through the pores of the landscape fabric and gradually build up inside the pipe. Another common cause of French drain clogs is root intrusion from grass, shrubs, and trees.
What can I do instead of a French drain?
Swales or Valleys Swales, also called valleys, are an alternative to French drains that capture and divert rainwater. Swales are shallow ditches that do not contain pipes. You can usually find them along a property’s edge, following the natural grade of the land to direct runoff to ditches or wooded areas.
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.
How much does a DIY French drain 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.
How far should a French drain be from the foundation?
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.
Can you 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 is the best rock to use for a French drain?
For the best drainage, look for coarse washed rock (gravel) that is screened, with a stone size of 1/2 to 3/4 inch. Smaller rock with fine particles could clog the holes of the drain pipe. Pea stone works, but the smooth stones settle together and don’t move as much water as coarse rock.
What is the best stone to 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.
Is #57 gravel good for drainage?
Crushed Stone #57 This type of gravel, made from machine-crushed stone, is also a popular choice for landscape design and for constructing French drains, as the size and shape of the rock fragments promotes proper drainage and prevents the gravel from locking together to form an impervious surface.
