# What is the correct way to install a French drain in clay?



## cnet24 (Jul 14, 2017)

Hello- I am looking to install a French drain to help with a muddy area in my backyard and wondering what is the correct way to do so? I've researched online and YouTube via apple drains, etc. and have found so many videos defending both wrapped and un-wrapped drains. Each video I see seems to contradict the others. So, what is the best method for Georgia red clay?


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## wiseowl (May 25, 2020)

Here's what I did in California clay. Dug my trenches a spade shovel width, about 11 to 14" wide and maintained a 2% grade from the back yard down to the front out to the street. This is key to good drainage as well. I used 4" sdr35 perforated piping ( https://store.ewingirrigation.com/25002380-4-inch-sdr-35-perforated-solvent-weld-sewer-pipe ) and used non woven geotextile filter fabric, can't find what I used on Ewing's site but they have it.

I laid the fabric down into the trench and put 3/4" gravel down into the trenches to create a base layer. I then put the perforated piping in, holes down, glued it up and then back filled with 3/4" gravel. I probably went about 2-4" top and bottom of gravel before I wrapped it all up like a burrito and then back filled the remaining trench with my clay. You have to dig as deep as you need to maintain your grade to the front of the house. You can see I ran my drains under my laterals which were roughly 6" deep before I laid my own sod.

It's worked a treat. I followed French drain man's walk through and apple drains and kind of blended the two. I didn't like the corregated piping we get from NDS here at Ewing or site one and wasn't willing to spend the non trade price with french drain man on his piping so I went with the standard sdr35 stuff. I have had zero problems in rain with my setup and even when I run my irrigation I will see water run out to the street drain, when I do long cycle and soaks, so I know that they're working as intended.

Because threads are worthless without pics:


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## cnet24 (Jul 14, 2017)

Thanks @wiseowl. There is so much information out there that contradicts it will make your head spin. I was weary of the burrito but I think at the end of the day what matters with clay is the fabric that is used.

How long as your drain been operational?


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## Easyluck (Feb 5, 2019)

How you watched this video?

https://youtu.be/JhmVT9FO72I

Fabric will keep the soil separated from the rock. The rock and the pipe will move ground water.


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## wiseowl (May 25, 2020)

cnet24 said:


> Thanks @wiseowl. There is so much information out there that contradicts it will make your head spin. I was weary of the burrito but I think at the end of the day what matters with clay is the fabric that is used.
> 
> How long as your drain been operational?


I put these in myself almost 3 years ago when I did all my irrigation and laid sod. There is a lot of random information out there for sure which is why I blended the info. There's videos out there of corregated being crushed where as sdr stands up. I mean it's just a home lawn, I'm not driving trucks on it so either would be fine.

The fabric is the key whichever way you do it. There's a bucket video somewhere of the fabrics for french drains that shows the difference. Definitely want the non woven geo textile fabric.


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## MGC (Jun 4, 2017)

nice wiseowl ... did u happen to get any pics that u can post how u finished the drain at the street like depth and any fittings also did u install any catch basins anywhere in the system just asking i have got to do this in my backyard and tie in the gutter downspouts, in long heavy rains itsa mess .... the apple drains guy is so practical and down to earth and informative ,,,, cheers


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## cnet24 (Jul 14, 2017)

Easyluck said:


> How you watched this video?
> 
> 
> 
> ...


Yes lol, but I have also seen another video from that company directly contradicting the findings and conclusions in this video, hence the confusion.


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## wiseowl (May 25, 2020)

MGC said:


> nice wiseowl ... did u happen to get any pics that u can post how u finished the drain at the street like depth and any fittings also did u install any catch basins anywhere in the system just asking i have got to do this in my backyard and tie in the gutter downspouts, in long heavy rains itsa mess .... the apple drains guy is so practical and down to earth and informative ,,,, cheers


I don't have any pictures at the street but I did reduce at my last drain down to 3" and had to water trench a hole under the pedestrian walkway to the curb and core a 3" hole in the curb. No fittings just all slipfit and glue and have it setback from the cored hole in the curb just a bit for aesthetics. The key is maintaining the proper slope for the drain to the curb. This is the easiest way to do it 



 starts at 1:30 and ends at 3:00 , there may be some other stuff in the video but for every 100" the diff between two level points is your % grade. The literal hardest part is digging the trenches, everything else is cake.

We don't have enough rain, nor do I have any trees to really warrant a catch basin in my configuration. If you have a need I'd install one but if I ever need to clean out I've got my 100' Underhill I can feed into my down spouts with the flush tool (honestly though will never need it in my configuration). I also used flared end 4" for my down spouts do I could fit in drain covers/grates that I flip upside down and inset in the fitting with no glue so I can remove as needed and they keep snails and lizards etc out of the drains. It also helps with some of my planter boxes as you can see here

These are what I use









https://store.ewingirrigation.com/25052695-4-in-pvc-drain-grate


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## mjc440 (Dec 27, 2020)

If you don't have the vertical drop to get water away from that area you can also dig a dry well. I used the nds flo well for a couple of those in my yard. It was really difficult to dig a big enough hole though so I would recommend this as a backup option.


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