You need water moving away from the building, not pooling around or under it. In most cases, a properly sized gravel pad handles this naturally because the stone lets water pass through and disperse.
If your building sits in a low spot or at the bottom of a slope, you may want a simple French drain or a swale to redirect runoff. It doesn't have to be fancy. The goal is making sure rain and snowmelt have somewhere to go that isn't directly under your building.



