# Building a french drain



## Ontario Buckeye (Feb 25, 2010)

With water coming out of the down spouts, I bought a length of non-perforated pipe, a length of perforated pipe. I then dug a trench under my lawn in almost a horse-shoe pattern (the length really doesn't matter as long as it goes away from your house...it all depends on how much digging you want to do). I attached the non-perforated pipe to the down spout and ran it in the trench until is was around 3 feet from the house. I then connected it to the perforated pipe for the remainder of the trench. Using a sock and gravel, I then covered the pipe before topping it off with topsoil and seed. My lawn on top of that pipe is the best grass on the entire property. It is almost the same idea of a French drain, but you don't have an output nor a bubbler at the end. If you get a lot of rain, you can also put a T connection between the perforated and non-perforated pipes so that if the water does get backed up for some reason, it comes up 3 feet away from the house rather then right beside the foundation. Make sure you put a rodent guard or a case and grill over the T connection, so you don't have animals/foreign substances getting into your drain. I would recommend this for both sides of your house, as with new dirt, you will probably be putting down new grass. This might not be what you are looking to do, but I did this and will do this in every house I own. In my opinion, it is much better than rain barrels!


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## gruntman (Sep 19, 2008)

In colder climates how far down do you need to dig when you put down the pipe? 

I have seen perforated pipe at the box store that has some kind of peanuts wrapped in a sock around the length of pipe. Is that junk? am I better off doing the perf pipe crushed stone wrapped in cloth myself?

How do you deal with debris that comes down the drain pipe? Some type of catch basin installed near the beginning of the pipe? I dont want this thing getting clogged.


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## Ontario Buckeye (Feb 25, 2010)

Well, I only went down about a foot and a half. It doesn't really matter how far you go, because it is your lawn. I have never used the pipe that you are talking about, so I can't make comment if it is junk or not. I have the cloth sock that I wrapped myself. As for the debris, it all depends on your surrounding area and your eave-troughs. I installed a piece of chicken wire at the top of my down spout, so that the big leaves don't even make it into the spout. For the little stuff, I have a little clean out that I cut into my down spout near the bottom. I cut a hole in my down spout that is about halfway through the pipe and about 6 inches in height. I cut it out using a jigsaw, but it really depends on the material of your eaves. Try not to mangle the piece you are going to remove...I used the removed piece as a cover for the hole. I inserted a piece of chicken wire and placed a piece of screening (from an old window) on top of it and secured both to the inside of the pipe, near the bottom of the hole. This collects all the little stuff that comes down without disrupting the flow of the water. If you have a lot of water coming down, you might want to use something a little less restrictive than the screening...possibly old pantyhose?. After my little filter was installed using a couple screws, I used the remove piece from when I cut the hole to make a door, so that it looked nicer. I had to cut the edges a little, but was able to have it so it is attached at 1 end and swings open and closed. I then used a little "hook" for lack of a better name to secure the door closed. It is barely noticeable and I only have to clean in out once or twice a year...usually around the fall. Here is a picture I found on-line that is similar to what I did


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## tbeaulieu (Apr 6, 2009)

Great discussion guys. I'd like to do this, as well.


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## Allison1888 (Mar 16, 2008)

*drainage*

Drainage is a tricky thing. We had a French drain system built in our last house and it worked great. Just make sure you look at the whole picture. I've seen people do French drains but not address basic grading issues, which can offset the water flow. Here's more on the whole drainage thing:

http://www.oldhouseweb.com/how-to-advice/fixing-a-chronically-wet-basement.shtml


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## tbeaulieu (Apr 6, 2009)

Agreed. In fact, I've got dozens of hours logged this spring so far, regrading ... by hand. Ugh!

We had/have a number of raised mounds that someone installed in the front yard many years ago. In my view they trap the water between them and the house. In fact, there's even reverse grading at portions of the foundation. I'm removing the mounding, sloping the ground away form the house. To make it even more fun, there's are old tree stumps (one took 2.5 hours last night!) and a number of bushes that I'm removing (and their stumps). 

Once I've got it all dug out I'll switch to drain mode. I'm also going by the water pattern's I observed earlier this spring and took pictures of.


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## AllanJ (Nov 24, 2007)

If you lay the drain pipes above the frost line then they could freeze up when full and just not function for awhile. You could get a big late winter rainstorm and the pipes are not thawed out yet and the result is simply as if you never installed the drain pipes in the first place.


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## Ontario Buckeye (Feb 25, 2010)

agreed...you may have a problem once a year. I have never had that problem with mine...again, not to say you won't. If you put them below the frost line, you receive none of the benefits...you might as well just get a non-perforated pipe and take it all the way to the ditch or catch basin. Plus, digging a foot and a half deep trench (properly graded away from the house of course) is a heck of a lot easier that digging a 4 foot trench. Also, the layer of gravel doesn't need to be 6 inches think...2 or 3 should probably be enough to disapate the water and allow enough room for top soil and grass.


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## tbeaulieu (Apr 6, 2009)

Why do you say none of the benefits by burrying the pipe below the frost line?

One a new house, that's where they'd put it these days. Why wouldn't I want to a) install french drains near the footer of my foundation and b) bring downspouts into similar setups, albeit not quite as deep?


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## Ontario Buckeye (Feb 25, 2010)

sorry, you get the benefits of proper drainage of water away from the house, but I worked mine into helping the lawn. Similar to Gruntman, I needed new dirt and new lawn and used the "wasted" water to build my lawn while moving the water away from the house. Gruntman seems more interested in his lawn drainage than his basement drainage. I am assuming that his weeping tile around his foundation is working fine and he is just trying to remove access surface water. I apologize for my choice of words and not clearly explaining the benefit I was referring to. I would definitely dig it down below the frost line if I was putting in drainage for the foundation. For downspouts, I use them as a sub-terrain watering system. No need for sprinklers when the water is already in the ground.


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## tbeaulieu (Apr 6, 2009)

OH! Gotcha!


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## gruntman (Sep 19, 2008)

My property is slightly slanted and drops off at the end over a small hill with a top of boulders. There are houses below. If I build the french drain and run the perforated pipe and gravel along the back yard (see string) shouild I just end it at the fence? I could install one of those pop-up emiters at the end. The one thing Im concerned about with that is if I run it shallow enough for an emmiter to work it will just freeze up in winter.


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## tbeaulieu (Apr 6, 2009)

I'd be careful not to send the water directly into the neighbors' properties. That would get you into trouble, for sure. I'm just learning this stuff, too, so I'm no expert. My feeling is that the emitter would be appropriate if you were looking to redirect water into a storm drain or an edge of your yard where it wouldn't adversely impact neighbors. If it were me I think I'd just run solid pipe for a short section and then switch to perf pipe. And I'd keep it below the freeze line. If I really wanted to go the extra mile I'd install dry wells as the final destination. In fact, I'm about to make this very decision myself in a few days...


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## AllanJ (Nov 24, 2007)

Ontario Buckeye said:


> For downspouts, I use them as a sub-terrain watering system. No need for sprinklers when the water is already in the ground.


I don't think that underground perforated pipes, even close to the surface, are going to do a good job of watering the lawn unless there are enough of them to cover the lawn less than 18 inches apart.


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## handy man88 (Jan 23, 2007)

Ontario Buckeye said:


> Well, I only went down about a foot and a half. It doesn't really matter how far you go, because it is your lawn. I have never used the pipe that you are talking about, so I can't make comment if it is junk or not. I have the cloth sock that I wrapped myself. As for the debris, it all depends on your surrounding area and your eave-troughs. I installed a piece of chicken wire at the top of my down spout, so that the big leaves don't even make it into the spout. For the little stuff, I have a little clean out that I cut into my down spout near the bottom. I cut a hole in my down spout that is about halfway through the pipe and about 6 inches in height. I cut it out using a jigsaw, but it really depends on the material of your eaves. Try not to mangle the piece you are going to remove...I used the removed piece as a cover for the hole. I inserted a piece of chicken wire and placed a piece of screening (from an old window) on top of it and secured both to the inside of the pipe, near the bottom of the hole. This collects all the little stuff that comes down without disrupting the flow of the water. If you have a lot of water coming down, you might want to use something a little less restrictive than the screening...possibly old pantyhose?. After my little filter was installed using a couple screws, I used the remove piece from when I cut the hole to make a door, so that it looked nicer. I had to cut the edges a little, but was able to have it so it is attached at 1 end and swings open and closed. I then used a little "hook" for lack of a better name to secure the door closed. It is barely noticeable and I only have to clean in out once or twice a year...usually around the fall. Here is a picture I found on-line that is similar to what I did


I assume you remove this for the winter.


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## Ontario Buckeye (Feb 25, 2010)

@AllanJ: It does't water my entire lawn...just a 4 foot cross section which happened to be the worst 4 foot cross section of my entire lawn. 

@Gruntman: Personally, I wouldn't run it to the back fence...bad drainage makes bad neighbors. As I said before and based on your pictures, I would loop it around my lawn. You remove water away from your house and you irrigate the spots where grass is having a hard time growing.


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## tbeaulieu (Apr 6, 2009)

I don't know about your local requirements, but I just stumbled across a ton of legal requirements I'm subject to in MA in order to dig a trench on my own property if it's deeper than 36". Being in New England, I had hoped to keep it below the frost line, which I think is around 42". 

So, either I'll keep it at 36", or I'll need a permit, barriers while unattented (plywood can't be used!) and it even mentions an insurance certificate when applying for the permit! Ugh.


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## Ontario Buckeye (Feb 25, 2010)

handy man88 said:


> I assume you remove this for the winter.


never have and it has never been a problem for me


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## gruntman (Sep 19, 2008)

I decided to go for it an dig the french drain. How much crushed rock should I purchase if the pipe is going to run for 30 feet? 1 yard? 2 yards?


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## gruntman (Sep 19, 2008)

Actually it is closer to 40 feet. Does anyone have a way to calculate how much stone to put down? Is 3/4 inch diameter the right size stone to use?


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## tbeaulieu (Apr 6, 2009)

If you google "gravel calculator" you'll find forms that let you figure this out. On the first page is "earth products". You'll have to figure out how wide and deep you want the gravel. Assuming 12" wide and 4" on the top and 4 on the bottom, plus ... say 2" for each side, that would be 2.2 tons. In researching my own project, I've found they usually sell gravel by the ton. And I've read that 3/4" is the correct size. Please keep us posted of your project. I'm getting serious about starting one of my own.


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## gruntman (Sep 19, 2008)

Started digging and ran into very large rocks. I was able to move all of them except one. Im thinking of using black landscape pipe to go around it and then switch back to perf pipe with holes on the bottom. These are the NDS containers I am deciding between.


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## gruntman (Sep 19, 2008)

Dug deeper - the rocks were boulders. I used the black perf pipe at the beginning and then switched to the solid with hole on the bottom wrapped by the sock. Covered top & bottom in 2 tons of 3/4 inch stone and wrapped the whole thing in landscape fabric. Threw left over stone and then the dirt on top. Had a storm last night and it worked great. 

A couple of things - I shoud have dug deeper; once I added 4 inches of stone the trench was no longer 3 feet deep. Buy 30 year professional grade landscape fabric - the cheap stuff tears easy and dirt gets in. Buy it wide enough (6 feet) so that you can wrap up the entire thing once you put down gravel on top of your perf pipe. I'll attach another pic when it is complete.


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