How to Install a French Drain, Step by Step Instructions
1. Prep Your French Drain Trench
After you’ve planned your French drain location you will need to cut the sod before you start your dig. You want the sod cutter to be set at the deepest notch so you have a nice thick piece of turf and all its root, because you will be using these pieces of sod to cover your French drain later.
Then you go ahead start digging. I know that homeowners do a lot of hand digging for DIY. It’s super easy to do hand dig in the spring. That’s when the soil is saturated and clay just cuts like butter. So I really recommend a hand dig in the spring.
Notice how we left the sod in order and kept it in tact so the pieces come together like a puzzle. Remember we will be using this sod to cover our French Drain after we install it.
2. Line the Trench with Non Woven Geotextile Fabric
Once you have your trench, then you have to go ahead and line it with either 40z or 8oz non-woven geo-textile filter fabric.
Notice how we take the fabric pins and we pin the fabric back. That’s so when you dump the stone in with your wheelbarrow, it doesn’t pull the fabric down to the bottom of the trench. Because that is exactly what will happen. So you go ahead and take your fabric staples, just punch them right through. The guys have a technique where they just do a quick strike and go right through the fabric.
Next we will talk about the French Drain pipe. Now, remember how we do things at French Drain Man. We put the French drain pipe at the bottom of the trench. That means it goes in before the stone. And if you have a sprinkler system, you want your French drain pipe underneath the sprinkler lines. So when you pull it, you want to pull it under all your sprinkler lines.
3. Pick the Best French Drain Pipe
Your next step is you want to pick a really good french drain pipe. And there’s only one purpose-built yard drain pipe out there – the High Octane. It is the blue pipe. It has more inlet than any other pipe in the world, and it’s the strongest single wall corrugated pipe in the world. High Octane was purpose-built just for yard drains and French drains. So you want to make sure that you use the very best pipe out there after you’ve spent all that time digging out all that clay! You want to make sure that you benefit from all that sweat equity that you put into your yard drain projects.
4. Place French Drain Pipe on Top of Fabric – Before Stone
Once you have your drain pipe we want to put it at the bottom of the trench – right on the fabric.
Why do you want your pipe on the bottom? So that you drain all the water out of your system.
When people tell you, “Oh, put three, four inches of stone down, then put down your yard drain pipe,” that’s bad information. Because you’re not going to get the water that’s laying in that stone that’s three inches underneath the yard drain pipe. You’re not going to get that out of the trench. So the trees and shrubs in the yard and landscape, they sniff that water out and the roots fill your french drain. And now your french drain has an expiration date.
5. Add High Quality Stone like Round Rock
Once your French Drain has been prepped and the pipe is at the bottom it’s ready for stone.
I get asked all the time, how do I install a French Drain and what stone should I use? I like to use a really big stone. The bigger the stones, the bigger the voids, because you want to feed this pipe. You want to be able to move that water as fast as you can. If you evacuate the water quicker, then you get less soil saturation to your yard.
Use inch and a half round rock, and make sure it’s round rock. Search long and hard for round rock. If you can’t find any, use inch and a half in crushed, but make sure it’s screened.
Now, you can put bricks, blocks, I don’t care what, on this pipe to keep it down when you’re putting in the stone. That’s definitely something that you have to be careful. You’ll go to dump the stone in and it’ll push the pipe aside and the stone will go up underneath the pipe and you don’t want that. So have somebody stand on the pipe, put cinder blocks on a pipe, whatever you want.
6. Burrito Wrap Your French Drain System in Fabric
When you go to do your burrito wrap on your French drain system, you want to make sure not to overlap. I’ve seen drains where they do a heavy overlap. The water flows through this filter fabric just fine. The filter fabric always has a gallons per minute rating. This filter fabric is going to move water. It’s going to move 140 gallons per minute through a square foot of it. So what we want to make sure is that we don’t overlap. Sure, we want to pull them together, we want to keep the dirt out, but we don’t want to have a bunch of extra filter fabric. We’re just overlapping on top of one another, because that is going to create a problem. It actually, that will slow down your drains.
And keep in mind that once in awhile, you’re going to have to enter the drain. You’re going to have cable, AT&T, Comcast. Sprinklers too. You got to make way for them. And there’s just really no getting around that.
7. Cover Your French Drain with the Sod You Saved Earlier
Lay in each piece of sod one by one. They will be heavy because when you cut them with the sod cutter earlier, you should have cut it as thick as possible.
This will be plenty of roots and dirt to cover your french drain. If you put any more dirt the slower it’s going to work. So haul all of the remaining dirt out of your yard.
What’s Better? .. A Yard Drain or French Drain?
People always ask me, “Should I install a French drain or a Yard drain?” Well, that depends. A yard drain just catches surface water in yard drain catch basins. That’s it.
A French drain, well, that’s a different story. It’s pulling water from the subsurface. It is pulling water 365 days out of the year from your soil in your yard, so that your dog and your children and you can enjoy this yard. You’re not running around in that sloppy mess. If you’re watching this, you need a French drain, I’m sure. If you’re muddy, soft, squishy, yard drain, all that’s going to do is get rid of those puddles. It’s just going to take standing water away. That is it. But remember to use big stone like round rock.
How do I Install a French Drain – Final Tips
Following the above tips will give you a French Drain that literally lasts forever (over 200 years).
Remember, you’ll want to use a non-woven geotextile fabric in 4 or 8oz. Don’t buy the cheaper landscape fabric if you want your french drain to last!
Remember to put your corrugated pipe at the bottom of the trench on the fabric. Then put the stone on top of your drain pipe. A common mistake among contractors and DIYers is they put the stone at the bottom of the trench.
To learn more about how to install a French drain, and other outdoor drainage systems subscribe to the French Drain Man YouTube Channel. If you’re looking for the service in Southeastern Michigan, give us a call at 248-505-3065.