Use 4 to 6 ounce weight non-woven Drainage Fabric. These are the most commonly used weighted fabrics to line a french drain. It provides great flow through rates and is strong enough to last the life of the drain. Ultra-thick rip rap fabric (8 oz +) is best used in erosion control applications and not french drains.
You want a 4 or 6oz non woven geotextile such as Mirafi 140n or 160n wrapped around your gravel. They make it in 3' rolls just for the purpose of french drains.
A french drain needs a non-woven geotextile wrap around the stone. Otherwise fines will enter the stone long term and reduce the effectiveness of the system.
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.
Landscape Fabric vs Drainage Fabric. Landscape fabric / drainage cloth is used in landscaping for water to pass through. Drain Field fabric is used in septic drain fields as a filter. They both act as a barrier, are from the same class of synthetic textiles and are similar in their construction.
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.
Use 4 to 6 ounce weight non-woven Drainage Fabric. These are the most commonly used weighted fabrics to line a french drain.
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.
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.
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.
Cover the pipe with about 3 inches of gravel or crushed stone, but not enough to cross above ground level. filter fabric over it for another layer of protection.
Landscape fabric is a woven cloth that is primarily used to suppress weed growth and separate different layers of materials in garden beds. While it can also be used for erosion control, it is generally less intensive in its applications compared to geotextiles.
Clogging and Blockages
Clogging is one of the leading causes of French drain failure, often due to root intrusion or sediment build-up.
Geotextile drainage fabric can help prevent soil erosion by providing a stable base for soil and prevent it from being washed away by water. The fabric acts as a barrier, allowing water to pass through while holding soil in place.
With fine-grained backfill like clays or silty soils behind the drainage gravel, filter fabric may not be required. These types of backfill can clog and obstruct the permeable filter fabric, increasing hydrostatic pressure and the chances of wall failure.
One step you can take is to install a filter or strainer at the inlet point of your French drain. This can help catch larger debris before it has a chance to enter the drain and cause a clog. Just be sure to clean or replace the filter regularly.
Interior French drains are meant for waterproofing the basement or draining your crawl space. They cost more because contractors must tear out the basement floor (most often made of concrete), install the drain, and then repair it.
If trench drains channel water that has pooled on the surface of your yard away from your house, French drains manage ground water or water that doesn't necessarily pool on the surface, but rather seeps through the ground immediately.
Dewitt Non-Woven 12-Year Landscape Fabric
While many landscape fabrics only last a season or two, this hardy fabric from Dewitt claims it will last for up to 12 years, making it a great choice for any garden area where you'd like to cut down on weeding permanently.
Cons of Landscape Fabric
As the fabric becomes clogged, adequate amounts of water and air are unable to to reach the plant roots, leading to the plant's decline. ✗ Earthworms, which aerate the soil, don't develop, leading to compacted and unhealthy soil.
The use of landscape fabric is a common practice among professional landscapers. It is often used as a base layer for mulch or decorative rock and under pavers or walkways to help prevent weeds from growing through the cracks.