French Drain Vs. Trench Drain: What Are The Major Differences?

Heather Robbins
by Heather Robbins
There are numerous sorts of drainage solutions available today. Each performs best under specific situations, making drainage choices crucial. So, what about french and trench drains? What’s the difference? The

There are numerous sorts of drainage solutions available today. Each performs best under specific situations, making drainage choices crucial. So, what about french and trench drains? What’s the difference?

The key distinction is that French drains catch and remove groundwater, whereas trench drains quickly remove surface water before it saturates the ground. Although both structures are the first line of defense against onsite water collecting, the trench drain is a surface structure and the french drain is a subsurface structure.

Water can be removed from a property and directed to the right channels in a variety of methods. The differences between French and trench drains, which are both utilized to convey water offsite, are sometimes misinterpreted.

Understanding the differences between a French drain and a trench drain can help you see why a trench drain’s adaptability is preferable.

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About French Drains

Perforated pipes are used in French drains, which are surrounded with gravel or sand and landscaping fiber to keep the drainage material from migrating. The landscaping material also prevents soil and roots from clogging or entering the pipe’s openings.

It’s simple to make by hand, but it’s best for draining water from gardens and around building foundations. French drains are best used on land that is frequently saturated from rainfall and prone to flooding because they direct trapped water to a specific spot.

Sloped Yards

In yards that slope toward a building’s foundation, one concern with French drains arises. If the slope is larger than one and a half inches, a surface drainage system is more appropriate. This is because if there are drainage concerns, a steep slope can cause excessive water to infiltrate beneath your property, and the drain’s subsurface construction makes it more difficult to reach.

Natural water flow may be disrupted by digging, and weeping tile or perforated pipe is prone to clogging over time. Furthermore, if there are electricity, communications, or water lines underground nearby, installing French drains can be problematic.

How Pipeless French Drains Work

French drains are gravel or rock-covered trenches. They have a perforated pipe that sends surface water to a septic tank or drain field from a specific region. The drains are often erected around the outside perimeter of the foundation or put beneath the basement floor on the inside perimeter of the basement in most homes.

When it rains heavily, your home is protected from sub-surface water accumulation, and water is routed away from any underground areas of your property. French drains are hidden because they are buried beneath the dirt or rocks.

These drain systems can last up to ten years if they are properly maintained, but they must be inspected on a regular basis. Flooded basements and other issues might result from a clogged French drain line.

About Trench Drains

Trench drains, also known as channel drains, are a type of above-ground drainage system. Its elements are encased in a long, narrow trench in the ground. It features a grate on top that resembles guttering.

Trench drains in residential areas divert water away from locations where it could cause damage, hazard, or erosion. To maintain the environment, the trench drain is connected to a local storm sewer or canal after it is installed.

These come in a variety of grate strengths and look to match the surroundings of a home. Because of its surface exposure and strong materials, it can withstand big weights without being damaged. Patios, pools, driveways, and walkways benefit from ABT’s pre-cast and cast-in-place materials, which give a permanent and lasting fixture.

What’s The Difference Between French Drains And Trench Drains?

Aside from what we’ve already mentioned, the difference between a French drain and a trench drain is that a French drain is utilized for underground water, whilst a trench drain is used to channel surplus water from the surface.

The trench drain is lined with concrete and slopes to drain away from your property using gravity. Both should be installed only after consulting with experienced drainage experts, as you risk disrupting other underground lines and the ecosystem’s natural water flow, which could result in new problems.

Installing French Drains

Gravity will direct the water with a slope of around 1% (or 1 inch every 10 feet) while building French drainage. Here’s how to dig your own French drainage system and install it on your land:

  • Decide on a location. Examine where surplus water is accumulating and where you want it to go. Water should always be directed away from your home or property.
  • Make a trench. 9-12 inches wide and 18 inches deep is a good size.
  • Line your trench with a weed barrier or water-permeable filter fabric. The pipe will not be contaminated by tree roots or dirt as a result of this.
  • Spread a 3-inch layer of gravel on the ground. This will allow for more drainage.
  • Put the pipe in place. Consider installing a small grate on the surface of the water where it collects the most. If you’re using PVC plumbing, drill holes every 6 inches or so all the way down the pipe. Install the pipe in the trench and test it to make sure it’s working properly.
  • Add additional gravel on top. Cover the pipe with additional 3 inches of gravel or stones. Wrap any leftover filter fabric around the pipe for added protection.
  • Backfill with top-soil as desired.

Installing Trench Drains

When it comes to trench drainage, the procedure is pretty similar. You identify where you need to dig, dig a trench, and install an open-sided drain pipe (similar to a roof gutter) that is covered with a metal grate rather than gravel and fabric.

Pipe and gravel are being inserted into a seam bored into the ground.Trench is a surface grate frequently in or edging hardscape: French drains are built below softscape.

Which Direction Do French Drain Holes Face?

When building piping for French drains in gravel drainage systems, the holes should face down so that water may easily enter the pipe from the button. If they were at the top, the water level would have to reach the pipe’s top before it could wash away within.

How To Choose Grates For Trench Drainage

From pedestrian walkways to industrial loading docks, cast iron trench grates provide adequate drainage. They’re made to quickly remove surplus surface water so that pedestrians and vehicles may safely pass over.

They can be carved and designed in a range of styles, from industrial to beautiful, to match their surroundings.

Cast iron is designed to last in any environment and can even handle heavy loads. Grates should be built to last, but they should also be attractive. Design contributes to people’s comfort and enjoyment of public spaces.

Cost To Install Trench Or Channel Drain

Depending on the grate and channel type, trench drain installation costs range from $30 to $150 per linear foot (plastic, metal, or concrete). Trench drains with a flush grate top that captures water in a channel are installed in driveways, patios, concrete slabs, or between pavers.

Driveway Trench Or Channel Drain Cost

Installing a driveway trench or channel drain can cost anywhere from $400 to $2,400, depending on the size, channel width (4″ to 8″), and grate material (plastic, metal, fiberglass, or concrete). Water cannot pool or enter the garage because of driveway trench drains or floor drains.

French Drain Cost

For around the house, yard, and curtain drain systems, exterior French drain installation costs $10 to $30 per linear foot, or $1,000 to $4,000. For crawl space and basement drain systems, interior perimeter French drains cost $40 to $85 per linear foot, or $4,000 to $15,000 total.

A French drain is a slanted trench filled with gravel and a perforated pipe that uses gravity or a sump pump to divert water away from a home’s foundation or basement.

Exterior surface water is diverted from around a house by shallow French drains or curtain drains. Interior perimeter French drains around a basement floor absorb water that seeps in and channel it to a sump pump or drain line, rather than preventing it from entering the basement.

Weeping tile drains, also known as deep footing drains, run around the perimeter of a house to prevent groundwater from entering the basement.

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Related Questions

Should I put in a French drain?

If your primary issue is flooding in the basement then you would benefit from installing a deep French drain, or even footing drain.

This will go around the perimeter of your house to help drain any water before it seeps into the basement. If your home is already finished this can be tricky to install but it’s definitely possible.

How do you unclog a French drain?

To unclog a French drain you will need a sewer snake, pressure cleaner, and also a drain opener. Dump the drain opener into the drain and let it sit for 4 hours.

After the chemicals sit, use the pressure washer. If you notice water backing up, the clog is still there and you will then need to snake the drain.

Heather Robbins
Heather Robbins

Heather is a passionate writer who loves anything DIY. Growing up, she learned everything from home repairs to design, and wants to share her tips with you. When she's not writing, she's usually hiking or searching for her next DIY project.

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