We are thinking about sealing our basement walls(block) with some type of water proffer. In two of the corners we have noticed some dampness and white powder coming out of the walls. For the most part, I think I have corrected the dampness problem with drainage out side the house. Is there a specific product you would recommend? I've been to HomeDepot and Lowes and found a verity of products like DryLock and Theroseal.