First, thanks for the good info- it got me started. But I have another question:I dug down to the footing of the foundation(I think that's what it's called), where I've come across a layer of rocks. Below the rocks I found a black plastic (ribbed) pipe with slits cut into the top of the pipe,- about every 2inches. I believe it's part of what is called a perimeter drainage system. For my case, I believe, that should be sufficient drainage and I don't have to dig below this level. By the way, where does this perimeter-type drainage system drain, i.e. away from the house?