Family Handyman DIY Tip of the Day: Inexpensive Wet Basement Solution. Sloping the soil away from the house will take care of the problem most of the time. Firmly pack clay soil around the foundation, with at least a 4-in. slope over the first 4 ft. Place 6-mil black plastic over the soil and cover it with landscape rock. Install 4- to 6-ft. gutter extensions to your downspouts to direct water farther away from your foundation.