Hi, I just recently purchased a home, and noticed that since the frost has thawed, one of my deck posts/footings has heaved up. I live in a very clay area that does not drain very well. I will be installing a french drain around my whole backyard and near the deck footings that go to a well and get pumped out. I just dug down next to the one bad footing and noticed that they are plenty deep. (I stopped digging at 50", frost averages 42 in my area) Is there something I could mix in with the clay next to the footing to help drainage? (IE pea gravel?) The whole way down was solid wet clay. I am hoping my french drain will alleviate the standing water issue, but since I already have a hole, should I add anything else?