Expert: Ted Barnhill (Principal, Design45 LLC) - 10/11/2008

Question
I have recently moved into a home that has a sunken patio with a walk out basement.  The current (and inadequate) drainage is simply a drainage hole that goes down into gravel.  It backs up with heavy rain and floods the patio and recently it flooded into the basement.  Please advise on the proper drainage system for this.

Answer
Ed,

There are three usual solutions:

1. Run a drainage pipe to "daylight".  That is, if you have enough grade change on your property, bury a pipe that slopes downwards, emerging and discharging at the surface downhill somewhere.  If your lot is fairly flat this may be out of the question.

2. Build a dry well.  This is essentially what you have, but if done properly can accommodate quite a lot of water.  Essentially you pipe the water to a deep, gravel-filled hole.  The well can be a store-bought plastic or concrete cylinder, or something homemade, or simply gravel in filter fabric.

3. If neither of these work (perhaps your soil won't percolate enough for a dry well), you may need an electric pump to lift water from your sunken patio's drainage.

For specific tips on each of these options, I would consult a landscaping and/or plumbing expert, here or on a site such as Terry Love.  Good luck, Ted.