What Is A French Drain and How To Install A French Drain Around Your House?

Maybe you have ever seen water collecting on your yard to form a pool that prevents grass and flowers from growing.

You might also be experiencing a situation where the drainage around your home’s perimeter is causing wetness in the basement or your driveway is completely washed out.

The best solution is to hire a professional Sydney plumbing company and set up French drains. While this type of drainage has a European name, it’s a commonly used drainage solution in most parts of the world.

henry french portrait

Henry F. French c. 1866

French drains are named from a Massachusetts based farmer who was known as Henry French. He constructed the first-ever French drain in 1859. This kind of drain is built underground.

The drain is basically a trench that slopes at an angle. The trench contains gravel and has a drain pipe that is perforated.

The pipe is covered with landscape fabric and drain rock. The drain works by draining water away from the areas you don’t want standing water.

It channels the collected water to an area where it’s stored and pumped away or absorbed by the soil. The drainage may be used outside or inside the home.

If you need such drainage in your home, then installing a French drainage system would be the best option.

 

Solving Drainage Problems in Your Backyard

If your yard has a poorly draining type of soil or large depressions, then water may stand and form pools. Standing water pools may create more problems.

For instance, standing water offers a perfect breeding ground for mosquitoes. Moreover, it drowns the surrounding vegetation, thereby making the affected yard area unusable.

A good method of channeling the standing water to other areas of your yard, dry well, or the street is by installing French drains. French drains are also known as curtain drains or shallow French drains.

The shallow type of French drains come with a trench that has a width of approximately 12 inches. Its depth is typically between 12 to 24 inches.

It’s good to note that the minimum slope of the trench should be 1 inch for every 8 feet towards the location where water is being directed.

The trench is lined with some landscape fabric and its bottom is filled with gravel. A perforated 3-inch drain pipe is then set on top of the gravel. The drain pipe is backfilled with drainage rock.

A landscape fabric is then folded over the drainage rock. You can cover the fabric with topsoil. You can as well plant grass over the soil to keep the drainage hidden.

It’s common practice for a shallow type of French drain to be built in an area that is a little bit higher in elevation than where the water pool stands.

The design allows the water flowing towards the depression to flow into the drainage rather than adding to the standing water. As such, the standing water drains without more water flowing into it.

 

french drain

How to Prevent Water from Seeping Into the Basement

If your home’s foundation is laid on a flat surface, then it can form a depression on which surface runoff collects. The water flowing from the roofing can also collect on the depression.

In this case, you’d need to construct a French drainage around your home’s perimeter. You can also call it a footing drainage system.

It channels surface runoff and water from the roofing away from your home’s foundation, such that it won’t seep into the home’s basement.

Another name used for this kind of a drainage system is deep French drainage. This is because the drain has to be dug to reach the home’s footing, which can be at least 2 feet deep.

The best time to construct this drainage is when constructing a home. Constructing it afterward is more challenging and expensive since it might demand moving shrubs, walkways, and decks.

 

Using French Drainage in Flooded Basements

If your house is built on an area where groundwater is high, then you’ll have more drainage problems besides surface runoff.

Hydrostatic pressure from the groundwater can push water upward through the slab or the concrete foundation, thereby flooding the basement.

While this problem is common in areas that have high groundwater, you can handle it effectively by constructing a French drainage.

Installing the drain in existing basements is quite expensive since it will involve breaking through a concrete floor. You might also have to redesign the floor for it to slope towards the drainage.

When installing the drain, you can design it to direct water towards a tank, from where it will be pumped from the basement.

You can also design the drain to collect groundwater before seeping into your home’s basement. Here, the drain works by catching water that may be seeping from below.

Alternatively, you can cover the drainage pipes with concrete to hide the entire French drainage system. In this case, the drainage is usually referred to as a tile drainage.

 

plumber installing a french drain in the backyard of a house

Tips on How to Install a French Drain

  • The most crucial part of any French drain is the drainage pipe. You may use a flexible drainage pipe that has slits or a rigid PVC piping with holes. If you’re installing a rigid pipe, ensure the holes are positioned toward the direction that the water flows from. In case you’re controlling groundwater, then ensure the holes are facing downward. If you’re dealing with surface water, then ensure the holes are facing upward.

 

  • You can improve the flow of water into the drain pipes by installing some catch basins. You can get the basins from your local hardware store. The basins are designed in such a way that they’ll fit perfectly on the drain pipes. The basins come with a grid that can be removed to make it easier to clean the drainage whenever the pipes clog.

 

  • It’s necessary to have a French drainage system when constructing a retaining type of wall on hilly locations. In this case, the drain should be constructed along the wall’s uphill side to catch any water that may be flowing downward, thereby preventing it from damaging the wall.

 

  • If you’re installing the French drain in an area close to trees or shrubs, the best pipe to use is a rigid pipe. The pipe shouldn’t be perforated within a distance of 10-20 feet away from a tree or bush. Doing so will ensure the roots don’t penetrate the drain pipes and clog them. However, if the roots eventually grow through the pipes, you can introduce some salt into the drain through the cleanout or catch basins to kill the roots. Thus, it’s advisable to ensure the drain has a cleanout when constructing it.

 

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2020-09-30T20:23:44+10:30