Landscaping a Sloped Lot

Retaining Walls
Retaining walls prevent soil on an embankment from washing away in the rain and can be from a foot tall to much higher, depending on the severity of the slope. The Timeless Home lot required walls that rose from 1 to 4 feet in the back of the house to 15 feet in the front. According to Roger Cook, there are three or four different types of wall you can build. “Riprap walls, where boulders are stacked on top of each other without any mortar, are the least expensive,” he says. “It's a real rustic look.” Alternatively, landscapers can use pressure-treated timber, concrete, segmental retaining-wall block, or fieldstone. But it's the labor involved, rather than the material, that most affects cost. “Masonry fieldstone walls are the most expensive because they are extremely time-consuming to build,” says Roger. “Concrete walls may be the strongest when engineered properly, but there is some expense involved in digging and pouring a footing. And remember, when this is all done you still have concrete to look at.”

Because the Timeless Home sits on a lot that is partially in Atlanta's 100-year floodplain, Wilfer and builder/owner Jason Yowell had to erect two reinforced walls on either side of the steep driveway that serves as a bridge over the flood area. “The high side's 15-foot concrete wall has a 5-foot-deep footing, and there's a tremendous amount of tied steel in there,” says Yowell. “Forming it was like pouring the home's foundation walls.”

Walls like this also require a drainage system installed along the base of the footing to keep rainwater from collecting next to the concrete. Yowell used a “French drain” — a 4-inch perforated pipe surrounded by gravel. Once the pipe and gravel are laid next to the footing, they're covered with soil.