Tuesday, September 22, 2009

Canalisation Francaise

In other words, French drain.

A torrential rain sent water into the window well of our basement, creating a leak and a big mess. Carpet, ruined. Refrigerator, unplugged; beer, wine and flower bulbs relocated to the kitchen fridge. Old dust bunnies in corners, drowned.

After the initial mess was cleaned (it would take a week to professionally dry the carpet), I realized I had a mere 3 hours until the next huge storm was predicted to arrive. I couldn't risk relying on the weatherman to be wrong.

The little swale I had created the spring before had well, unswaled. I needed something that would drain water away from the house, not refill within a few months and only take a few hours to build. Having designed and studied how french drains work, it was time for me to spring into action. Pulling out some old notes, I took some measurements, drafted a quick sketch and was off for a quick trip to the nearby hardware store (the old-fashioned (read: expensive) local one) as the looming thunderclounds didn't allow for a trek to the large national chain store.

Shopping List:

12 large bags of pea gravel
black mesh "landscape fabric"
new shovel (why not)

Once my materials were in hand, I dug and dug and dug an 8" deep and 12" wide trench from the area before the water began to pool, about a foot away from the house. To make sure the water would flow away from the house, I poured a small amount of water into the trench until I could see it flow the entire length to where the trench met the grade of the lawn. Once I was sure my trench was properly sloped, I laid a long strip of landscape fabric in the trench, and filled it with pea gravel about 4" across and 2-3" deep. Then, folding the landscape fabric around the gravel, I created a small tube of gravel. Last, I filled in the rest of the trench some dirt and topped with a couple of inches of pea gravel.

For once, the weatherman was right on target. About 30 minutes after finishing my work, the second storm - worse than the first - arrived and my new French drain worked like a charm.

Merci beaucoup to Henry French.


  1. Congratulations on your emergency drainage project working out!

    I'm planning a bigger project for my house. Been using this online guide to landscape drainage . It has instructions on building a French Drain that sound different from what you did?

  2. I checked out the website you mentioned and it is indeed very thorough. If your project is large and you have some persistent water problems, their instructions appear to be a good guide.

    My particular problem is very small - you might be able to see that there is a 3' strip of land (the gravelly area) about 12' long between a dry stack stone retaining wall and the side of my house. In very heavy downpours, the water from my neighbor's property, combined with the water that just hits the ground, flows down this area and into and across the lawn. The grade is very, very slight and with a series of heavy rains, there is more water coming from the retaining wall. The slight grade is not enough to carry large quantities of water with out a little assistance. To address this issue, the grade just has to be away from my house and down to where it can flow into and across the wide span of my lawn. Again, my example is a very simple and small issue.

    Good luck with solving your drainage problem!