Channel drains, trench drains or strip drains are linear drainage applications used to prevent surface and rain water from flooding garages, basements, driveways and gardens.
Channel drains are straight drainage strips that collect and convey surface water. They can be found on driveways, around pools, parking lots among other places. Channel drains are an effective way to collect water before drainage issues arise. Excess water around a house can seep into a basement and cause water damage. Water can also pool around landscaping and cause damage to the exterior of a residence.
There are a few different channel drain manufacturers such as NDS, Polycast, Rainbird, Source 1 and Swiftdrain. It may get confusing when you find cheap channel drains for $100.00 on Amazon and are wondering what the differences are to the ones that cost more. The thing is, what you spend now is what you will save in time, cost and redoing a job later. There are cheap channel drain options, but they simply don’t last. Basic residential kits go for about $50.00 a linear foot. This would include a metal grate, end cap, end outlet and channel. For a 12 foot garage section, one can expect to pay about $600.00 in channel drain materials.
One of the first things to consider is how much water we need to drain. There are complex ways and simple ways to calculate water runoff. The simple way can be calculated with this flow chart.
We need to know how much water we will have to drain in order to select the right depth, width and length of the trench drain system. Typically, a 6”, 8” or 12” wide channel is sufficient. Without going too crazy with flow charts and formulas, if you have moderate pooling or drainage issues go with a 6” or 8” and if you have severe pooling and drainage issues go with a 12” wide channel drain.
When selecting the right channel drain the following must be taken into consideration:
- The slope of the surface where the channel drain is going
- The amount of water to be collected
- What will be going over the channel drain (cars, people, pets)
- The slope of the ground leading to the channel drain affects the speed and volume of water the channel will carry. A simple and easy way of determining flow rates through the grates can be found here. Generally speaking a pre-sloped trench drain system sloped from .7% - 1% is sufficient for most residential applications.
- The amount of water to be collected can be determined by water tables flow charts. This will help us determine the width of the drain. For residential applications, 4” – 12” is usually the width selected. For most applications 6” is more than sufficient.
- What goes over the channel drain should be considered. There are different class load capacities.
- A – Pedestrians
- B- Small Cars
- C- Passenger Cars, SUVS and trucks
- D- Loaded Forklifts
Also, if you have animals or pets constantly going over the grates. Paw proof channel drain grates would be another consideration.
Channel Drain Grates
ADA grates or American with Disability Act are grates with holes (slots) that are smaller than 1” x 1”. This prevents crutches and wheel chairs from getting stuck when going over the channel drain.
Channel drain grates come in plastic, cast iron, galvanized steel, stainless steel and bronze. Plastic is suitable for pedestrian and light veichular traffic. Most manufacturers include U.V. inhibitors in the grate to increase its structural lifespan. Sunlight can cause damage and cause grates to warp.
Channel drains can also come furnished with frames or rails to give added support to the grates that sit on top. This will also increase the lifespan of the drain and minimizes the chance of shifting and breaking over time. It’s a slight additional cost now which increases the lifespan of the drain over time.
Decorative channel drain grates can also be used to give the driveway area an aesthetic charm. Urban Accessories, NDS and ACO carry a full line of decorative grate options. Grates can also come unpainted, bronze and with a baked on oil finish to give an added sense of design.
Catch basins can also be added to the channel drain system to collect leaves and other debris before they enter the pipe. Channel Drains should come with one end cap, one end outlet, channel, grates and screws.
Channel Drains V.S. French Drains
A French drain is a trench filled with rocks, pebbles or gravel that contains a perforated pipe and conveys surface water from point A to point B. A French drain can have hollowed out perforated pipes along the bottom to convey water that seeps into the ground system. French drains are useful to prevent water accumulation, foundation damage, retaining wall buildup and other septic tank uses.
French drain sizing depends on the expected water volume. Usually 2 or 3 pipes is sufficient for the drain. Filters like sand, gravel, rocks and pebbles are used to keep out particles from the surrounding soil. Gravel, stone and rock are used as permeable materials and placed around the pipe to help out with water flow.
French drains are usually buried around the foundation wall on the external side of the foundation or installed underneath the basement floor on the inside perimeter of the basement.
French drains can be a useful way to convey water but also have downsides such as expansive excavation, clogging issues and the need for a sump pump. We have seen that channel drains offer a higher success rate than French drain systems.
The most popular channel drains are the NDS Pro Series, Josam, ACO 100 and Swiftdrain Sierra. These channel drains have polymer and hdpe channels with a variety of grate options to choose from.
Driveway Channel drains should cost about $500.00 for a ten foot section. This would include an hdpe channel, metal grates, end cap and end outlet.