We get about three feet of rain a year and a lot of clay soil. That combination is what destroys patios, driveways and retaining walls, and it's the part nobody sees.

It takes about two minutes on the L&I website and it's the single best protection a homeowner has. Here's exactly how to do it.

Foot traffic in 24–48 hours, vehicles after 7 days, full strength around 28 days, and why our wet, cool climate changes the math.