During the spring months, as the weather starts to warm up and you want to start enjoying your backyard, you may be getting flashbacks of what your yard looked like in the fall and winter. You are most likely remembering that your space is unusable due to your yard being wet and muddy from accumulated surface water. To top it off, when the kids and pets come in from playing, they are always covered in wet grass and mud that gets tracked into your house. This can be super frustrating because you probably bought your house with the intention of actually using, and enjoying your yard! Luckily there is a fix. Putting in a French drain is the solution to drainage issues, effectively "waterproofing" your yard and will have you enjoying your backyard oasis in no time!
Back 40 Landscaping is the only company in the Lower mainland to use Baughman Tile for our French Drain systems, providing a fail proof drainage system each time they are installed.
A French drain system is a trench, usually filled with soil, gravel or round rock, that contains a drainage pipe. Its purpose is to absorb ground and surface water, and make it disappear to a designated area.
French drains transport water away from yards, and are a great option for fixing a wet, soggy yard. By putting a French drain in your backyard, you can change what would otherwise be a damp spongy lawn, into a useable one by getting rid of all that excess water.
A typical residential backyard is anything that takes 30 min or less to mow.
There are many different materials and methods that can be used to create a French drain. Each contractor designs and installs their system by using different materials, tools, and methods. This is the reason the cost of a French drainage system varies, and why some systems work better, and last longer than others.
Single punched: This landscape fabric has half the number of punched openings as the double punched fabric, and can easily lead to clogging because it restricts the flow of water.
Double punched: This fabric has a high-water flow, and will not get plugged. It comes in different thicknesses for durability and lifespan.
Black ADS brand french drain pipe (Big-o, with lime green stripe): This pipe is made up of recycled materials and has three small inlets sliced in every valley. It is flexible and quick to install, but clogs and crushes very easily. It is the cheapest french drain pipe, and the most used pipe locally.
White PVC perforated pipe: This pipe is a rigid pipe that is 3x the price of big-o. It has no flex to it, does not stretch, and can crack when the ground settles. Due to each pipe being 10’ long, it is the slowest to install, because each of the 10’ sections have to be primed and glued together. Lots of fittings are needed to get the pipe to curve around trees or other objects. Unless it is installed below the frost line (18 inches) it will crack when frozen.
Blue High-Octane pipe (Baughman Tile brand): This purposed built French drainage pipe was designed for the clay soil that the Fraser Valley has. It is extremely flexible, fast to install, and has an excellent crush rating. Due to its 8 massive inlets in every valley, there is open air exchange that can dry out the subsoil much faster than any other option of pipe. Baughman tile is the most durable of all of the pipes, but is the most expensive option.
Existing soil: The trench drain can be backfilled using the existing soil that was excavated. This soil is usually clay, since yards with sandy soil do not typically need a drain put in. Using the native soil as backfill will work until the original soil compacts again. This gives you effective drainage for 2 months - 2 years.
¾” clear gravel: Backfilling the trench drain with gravel will allow some water to pass through, however, it only provides the trench with a little bit of void space. This lack of void space limits it’s storage potential in a heavy rain, or snow melt event, and never fully dries out the subsurface.
1 1/2” round rock:
When round rock is used to backfill the trench, it allows for greater void space and air movement, creating an underground drying effect. When the subsurface is dry, it allows the soil to act as a sponge, and soaks up water during rainfall. Plant roots are healthier, and your lawn will not have a yellowish waterlogged look to it.
Amazingly, there are over 18 different combinations of methods that can be used by various contractors to build your French drain. The cost of a French drain installation is based on labor, tools needed to complete the job, and the effectiveness of the method used to install the French drain. Some systems will last centuries if the right materials and methods are used, while others can fail after only a few months after being put in.
The trench can be dug using two methods.
Digging by hand: When a trench is dug by hand this can be a very slow process, and due to it being so labor intensive, the proper depth may not be achieved.
Digging with an excavator:
Excavators are a way quicker way to dig a trench, and will be able to make it to the proper depth quicker than by hand. However, some space may not allow access for an excavator, and because excavated soil can expand up to 1.3 x its size, it can be nearly impossible to get the soil out of a yard unless the right machines are used. Skid steers or wheelbarrows can move the soil to a dump truck, where it can then be taken to be disposed of.
Fabric can be used in a number of ways in a French drain install. Its purpose is to keep soil from mixing with the rock around the pipe. Some contractors choose to use fabric, while others do not.
No fabric:
Not using fabric cuts down on the cost of installation. Without fabric in the trench, there is nothing from keeping the soil from penetrating into the pipe.
Fabric placed on top of the pipe:
When fabric is only placed on top of the pipe, the bottom and sides of the trench will allow soil to get into the gravel in the trench.
Fabric placed on bottom, sides and top of the trench:
When the pipe is “burrito” wrapped, no soil or debris can get into the system. By preventing soil and debris from entering the trench, there is no way that the pipe can get clogged, or backed up.
The purpose of the pipe in a French drain system is to “carry” the water away from the area that is water logged. The placement of pipe really makes a difference in how the drain works, and for how long it will work for.
Placing the pipe on dirt: If the pipe is laid directly on top of the dirt, the inlets of the pipe can get clogged. Once the pipe is clogged, the system will not be able to work properly and the water will become stagnant.
Placing the pipe on rock: When the pipe is placed on top of the rock there will always be standing water under the pipe. If you have standing water, tree roots will seek out the water and infiltrate the system.
Placing the pipe on fabric: When the pipe is placed on fabric, it there is no clogging as the fabric keeps dirt and debris from getting into the trench. Since the pipe is at the bottom, there will be no standing water in the bottom of the trench.
This is due to the wide variety of different ways to combine all of the systems, materials and methods that can be used. It would be impossible to inform you of each type of install, so here are three typical installs we see. Usually, these French drains are based on price, ease of installation, and effectiveness.
Cost: $5,000-$9,000
Materials used: Big-o pipe
Method: The trench is hand dug, big-o pipe is put in, and clay soil backfills the trench.
Pros of this method:
Cons of this method:
Cost: $9,000-$13,000
Materials used: PVC pipe, 3/4” clear gravel, single punched fabric
Method: The trench is dug with an excavator, ¾” clear gravel is dumped into the trench, pipe is placed on top of the gravel, more gravel is used to backfill, and fabric is laid on top.
Pros of this method:
Cons of this method:
Cost: $13,000-$17,000
Materials used: Blue octane pipe (Baughman tile), double punched fabric, 1 ½” round rock
Method: This trench is dug with an excavator, double punched fabric lines the bottom, and sides of the trench, and blue octane pipe is placed inside. 1 ½” round rock is used as backfill, and the fabric burrito wraps the whole system.
Pros of this method:
Cons of this method:
Some factors that can increase the cost of your French drain install
To give you an idea of how linear feet changes the size and price of a system, here are three examples of French drains being installed in the same yard, using the exact same materials. The more pipe that is installed, the greater the cost of the French drain will be due to labor and supplies. The plus side to this increase of pipe is that your system will dry your yard out faster after a rain event.
To truly decide what system and methods are best for you, and your yard, you need to decide whether or not you want to solve your water problems for good. Having to redo the system in a couple of months-years is not only frustrating, but costly, as your old system will need to removed and hauled away, before a new one can be put in.
When a French drain system is done properly, the pain of the project is soon forgotten when you see your system working. Nothing beats having peace of mind that you put in the best French drain you can get.