dcbrewer, thanks for the info regarding the plastic over the gravel and under the concrete. we are in the red clay area here and when we get rain, we get rain. the clay IS terrible. when it is dry , like it is right now, the clay is like brick. Our contractor is very knowledgeable, but I will raise the issue with him. we have a start date of either Thursday or Friday depending on how their current job progresses. We have discussed drainage under and around the pad and he has some good ideas about French drains behind the pad which will be a gentle downward slope. again, thanks. I will discuss your thoughts with my contractor.