Lawn regrading or other grading option

by Christine yee
(Seattle, WA USA )

I've been living in my house for 10 years. Never had water in my basement. Last March after a heavy rain, had water on my basement. Ceiling and walls were dry. Water was coming from the small crack on the floor. Had gutters cleaned and downspouts diverted 10 feet away. After a heavy rainfall, water still coming in. Soil around house doesn't slope away or towards the house. Just flat. No visible puddles on the soil around the house. My driveway is in the back of the house. At the end of the driveway close to the garage door, there's a floor drain draining lots of water from the driveway. I'm planning to have that scoped with a video camera to see where does that go and see if there's crack or leak leading to high water table causing the problem. 3 feet away from the house in the backyard, there's puddles of water due to clay soil. This puddles had been there after heavy rainfall 10 years ago and no water seepage. Which one do you think causes water seepage into my basement floor crack? What should I do first (video camera or regrading)? Need your expert advise. Having a hard to figuring out what's the problem so we can find solution

RESPONSE

Hi Christine,
There is a rule that all land must slope away from you house for proper drainage. Since your land is flat, I would take care of this first. There are actually two options.

1. Re-grade away from house at 2% or 1/4 inch per foot.
2. Install french drains along the perimeter where the soil meets the house. This drain must be pitched to lead the water elsewhere.

I had a similar situation at my own home, but the area inside was a slab, not a basement. Water was coming in. I re-graded one area where I could and installed a french drain in the other. Both worked out fine.

Susan