Once the drain is finished place a 2” layer of Stone on top of the French Drain. Then add another layer of Weed Mat across the French Drain then add a 2” Layer of Diamond Sand followed by Weed Mat and at least 4” of Top Soil.
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.
Cory, As you note, the ideal backfill material would be a granular, free-draining material like crushed stone or gravel. If you go that route, it's a good idea to install landscape fabric on top of the gravel to prevent clay particles from clogging the system.
French drains can also work fine covering with dirt. Since the water under the surface is being moved it gives the water on the surface somewhere to drain. The inside should be some kind of river rock on bottom and top wrapped and then back filled over top.
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. On the other hand, you would need around 0.6 cubic feet of gravel if you're using a 6" drain pipe.
Once the drain is finished place a 2” layer of Stone on top of the French Drain. Then add another layer of Weed Mat across the French Drain then add a 2” Layer of Diamond Sand followed by Weed Mat and at least 4” of Top Soil.
Consider a ½ cubic foot bag of stone or soil weighs about 50 lbs and will cover 2 square feet at 3" deep.
To prevent this, clean out and snake the French drain once a year. Whether you're performing interior French drain maintenance, basement French drain cleanout, or exterior French drain maintenance, you'll need an electric sewer snake. You can easily rent one if you don't want to buy it.
Clogging and Blockages
Clogging is one of the leading causes of French drain failure, often due to root intrusion or sediment build-up.
A French drain needs to be surrounded by gravel in order to filter out silt and prevent clogging the drain pipe.
Swales: A Natural Solution
They're a great option if you're looking for a more natural, eco-friendly alternative to French drains. A swale is typically lined with grass or vegetation that helps slow down and absorb water.
Clay soil has poor permeability, meaning it doesn't allow water to pass through easily. In such cases, the effectiveness of a French drain may be limited as the water may struggle to drain away from the area efficiently. French drains may not be suitable for areas with high water tables.
If installing the drain involves diverting a stream or affecting a wetland, you likely need a permit to move forward. Generally, a small French drain on your property that doesn't change the flow of runoff entering and exiting your yard won't need a permit.
Installing a French drain costs $500 to $18,000, with a national average of $9,250. On average, you can expect to pay $10 to $100 per linear foot, or between $500 and $5,000 to have a 50-foot French drain installed.
The trench should be about 18 inches deep and 9 to 12 inches wide. 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.
A French drain has a typical lifespan of 20 to 30 years, although this can vary depending on the quality of the installation and surrounding conditions. Regular maintenance and the materials used, such as PVC or crushed stone, play an important role in prolonging its lifespan.
Just like other types of drains, they are susceptible to clogging over time. Ideally, clean the French drain once every year.
8 cons of French drains
May require regular maintenance. Care must be taken not to hit utility lines when digging for installation. Installing them may involve digging up your yard or even pavement. If the pipe gets clogged, it can be difficult to find and fix the problem area on your own.
The minimum cover required when the drainage system is in a traffic area with drainage pipe diameters from 100 mm through 1200 mm (4”-48”) must have at least 0.3 m (12”) of cover over the pipe crown, while 1500 mm (60”) pipes must have at least 0.6 m (24”) of cover.
Among 15 choices, these Pea gravel Landscaping Rock have the highest satisfaction ratings with Lowe's customers. While these might be the highest rated, what you choose should fit your needs, so consider additional features such as Brand, Size and Color/Finish Family when making your selection.
At a depth of 3 inches, a cubic yard of material can be spread over a 10×10 area (100 square feet).