Savannah. Charleston. New Orleans. San Antonio. These colonial-era cities inspire the courtyard garden ideal: green and lush, with beautiful plants, pools and fountains, paved with stone, tiles or bricks, & protected by sheltering walls with gates that reveal a table and chairs for cocktails or an al fresco meal...

Friday, July 23, 2010

Parlez vous du drainage?

I’m sweaty and exhausted! I really wanted to be blogging in air-conditioned comfort, but instead have been hard at work outside digging a French drain. I know, I know, my best friend asked me the two obvious questions. 1) Why didn’t you hire someone? & 2) Why did you pick July? The answer to question number one is that it is located right next to my driveway and had to be dug by hand anyway. Number two? Because I was tired of looking at the corrugated pipe in my garage.

Why are French drains French? Do they come from France? Do they require cufflinks? Or are they cut at an angle like the green beans and bread of the same name? Should we call them “Freedom Drains?” They actually sound more Dutch or German to me, but it turns out that they are not French at all. Experts report that a man named French first described them as an open-trench drain filled with gravel. Read about it in Wikipedia or in this interesting article.

Courtyards, being surrounded by at least a couple of walls by definition, will usually have some drainage issues. The drainage should ideally be planned for well in advance and before any pavement is laid ~ unless you enjoy spending more money after replacing your living room’s parquet. My courtyard drains well and away from the house, but my mini-lawn gets waterlogged during heavy rains due to my driveway blocking the water’s egress toward the street, which is on lower ground. Hence, the French drain along the edge of the driveway.

I am using black plastic drainage pipe which is corrugated and perforated. The perforations allow water to flow in wherever necessary, and also to seep out anywhere to deeper soil, keeping all of it from being simply dumped unused into the street. The pipe is covered with a landscape fabric sock to keep it from filling up with sediment. So far, I have also installed three receptacles with grates:

along the way to allow for future high pressure garden hose cleanout. The protected pipe is finally covered with gravel, and massive quantities of diet cola beverages are consumed. Preferably TaB™.

For adequate drainage, the recommended slope is between 1:100 and 1:200, which translates to between 1/8 and 1/16 inch drop per one foot run. I could have carefully measured this out, but since my lawn’s elevation is fixed, and the level of my street is fixed, and the driveway naturally drains down to the street, I am simply keeping the depth of my trench stable in reference to the edge of the drive. If the tube does dip slightly lower in places, the resulting puddle will simply drain out the perforations. By the way, it is functioning really well! (It’s much more fun to test than to dig!)

I didn’t want the end of the pipe to be visible to my neighbors, so I disguised it with the help of some large, loosely placed river rock. C’est magnifique, n’est pas?


  1. Dear F, I have much enjoyed your weblog, having come across it by chance, for its beautiful presentation [putting my own somewhat to shame], its amusing and highly readable style and, not least, for the way in which it informs and is full of interest. I have signed myself as a 'Follower' in order to keep up with future activities!

    As for French drains, or what my gardener/handyman would refer to as 'land drains', I intend to inform him of all you say in the hope that, once and for all, he will do something about the standing water on the gravel sweep in front of my London house.

  2. Thank you, thank you for this post. I have to do something about the drainage in my own garden, and I was feeling a little confused. You actually made it look easy, although I am wondering about the grates that you placed along the way. I did not see them in the pictures, did I?

  3. I've added a picture of a receptacle similar to the type I used, this one from Home Depot. More pictures to follow upon completion!


  4. Thanks for the pic, looking forward to the next post.


Thank you so much for your comments. They are always appreciated!