and are most susceptible to heaving. A few ways to protect against capillary action responsible for frost heaves are placing foundations below the freezing zone or insulating ground surface around shallow footings, replacement of frost-sensitive soils with granular material, and interrupting capillary draw of moisture by putting a drainage layer of coarser material in the existing soil. Water can cause potential damage to earth shelters if it ponds around the shelter. Avoiding sites with a high water table is crucial. Drainage, both surface, and subsurface must be properly dealt with. Waterproofing applied to the building is essential. Atrium designs have an increased risk of flooding, so the surrounding land should slope away from the structure on all sides. A drain pipe at the perimeter of the roof edge can help collect and remove additional water. For bermed homes, an interceptor drain at the crest of the berm along the edge of the rooftop is recommended. An interceptor drainage swale in the middle of the berm is also helpful or the back of the berm can be terraced with retaining walls. On sloping sites runoff may cause problems. A drainage swale or gully can be built to divert water around the house, or a gravel-filled trench with a drain tile can be installed along with footing drains. Soil stability should also be considered, especially when evaluating a sloping site. These slopes may be inherently stable when left alone, but cutting into them can greatly compromise their structural stability. Retaining walls and backfills may have to be constructed to hold up the slope prior to shelter construction. On land that is relatively flat, a fully recessed house with an open courtyard is the most appropriate design. On a sloping site, the house is set right into the hill. The slope will determine the location of the window wall; the most practical orientation in moderate to cold climates is a south-facing exposed wall in the Northern hemisphere (and north-facing in the Southern hemisphere) due to solar benefits. The most practical orientation in the Tropics nearest the equator is north-facing toward the aphelion (or perhaps northeast) to moderate the temperature extremes. Just outside the Tropics, the most practical way to avoid afternoon heat excess may be an east-facing house or, if near a west coast, exposure of the east end and the west end, with the two long sides embedded in the earth. Depending