Gravel, Crushed Stone and Soil Delivery in Winston-Salem, NC

Sandy clay loam on rolling ground

The USDA soil survey maps the ZIP's center point as Poplar Forest clay loam, 6 to 10 percent slopes, moderately eroded. Poplar Forest soil makes up 85 percent of the map unit.^[1]

The texture recorded there is sandy clay loam. The soil is rated well drained and sits in hydrologic group B, so water moves into it at a moderate rate. Clay in the mix holds moisture and makes the soil sticky when wet, while the sand keeps it from sealing over completely.^[1]

Its shrink-swell rating is low, 1.5 percent. Sandy clay loam with a low rating stays fairly steady as it wets and dries, so slope and runoff are bigger concerns than soil movement.^[1]

The words moderately eroded point to a history of soil loss. On slopes of 6 to 10 percent, rain running downhill has carried some topsoil away over time, and bare ground can lose more in a single heavy storm.^[1]

The ground at the center point rises 860 feet above sea level.^[2]

Moderately eroded slopes lose their best soil first. Where the topsoil has thinned, subsoil with more clay comes to the surface, and grass and plants struggle in it. Restoring those spots with a layer of Topsoil mixed with Compost gives roots a better start.^[1]

Gneiss and schist below the hills

According to the USGS geologic map, the rock below the center point is Biotite Gneiss and Schist, a Neoproterozoic unit with biotite gneiss, mica schist, calc silicate rock, amphibolite and granitic rock. These are old, hard metamorphic rocks that weather slowly into clay-rich soil.^[3]

Mica from the schist can show up in the soil as tiny glittering flakes. Soil with mica in it feels slippery and can be harder to compact, so a base of angular crushed stone over fabric gives a firmer result than packing the native soil alone.^[1],[3]

Hard rock near the surface can stop a post-hole digger. If you hit rock while setting posts for a fence or a deck, shift the hole a little or use a breaker bar, and backfill around each post with #57 Crushed Stone so water drains away from the wood.^[3]

Rain, runoff and freezing nights

The NOAA station at Winston-Salem's Reynolds Airport, about 2 miles from the ZIP, averages 43.2 inches of precipitation a year. On sloped ground, that much rain means runoff, and runoff carries soil and loose stone downhill.^[4]

The airport station records 64 days a year with a low of 32 F or colder. Water trapped in a base freezes and lifts the stone on those nights, so a base that drains helps a drive or walk keep its shape.^[4]

The median last spring freeze at Reynolds Airport is March 26. The median first fall freeze there is November 9.^[4]

Gutters on a hillside house carry a lot of water. Run downspouts into buried pipes that empty well downhill, or onto splash pads of River Rock, so the water spreads out instead of carving a gully.^[1],[4]

Late winter thaws can soften the top of a drive while the ground below is still cold. Keep heavy loads off a new drive during a thaw, and wait for it to firm up before you grade.^[4]

Drives that climb

On slopes of 6 to 10 percent, a gravel drive behaves like a channel in a storm. Water runs straight down the wheel tracks and carries stone with it. Break the flow with a shallow, angled trench filled with #57 Crushed Stone or Drain Rock across the drive every so often, sloping to one side.^[1],[4]

Strip off loose topsoil, lay fabric over the sandy clay loam, and compact Road Base in thin lifts. Finish with Driveway Gravel, whose blend of sizes locks together and resists sliding better than clean stone. Avoid round Pea Gravel on any slope, since it rolls downhill under tires and feet.^[1]

Along the downhill edge, Riprap or #4 Crushed Stone lines a ditch where runoff collects, and the heavy stone stays put when fast water rushes through. Bed it on fabric so the soil underneath does not wash out.^[1],[4]

Steps cut into a slope need a firm footing. Dig each tread level, compact a layer of Road Base, then set timbers or stone and fill the tread with Walkway Gravel or 3/8" Crushed Stone. Angular stone holds on a step far better than rounded stone.^[1],[4]

Water gathers at the bottom of a slope. A French drain lined with fabric and filled with Drain Rock along the low edge of the yard carries it off before it soaks a lawn or reaches a foundation.^[1]

Walls, terraces and garden beds

Terracing turns a slope into usable flat ground for beds and patios. Retaining walls need clean backfill: place Drain Rock or #57 Crushed Stone behind the wall, wrapped in fabric, with a perforated pipe at the base. Water drains out instead of building up behind the wall.^[1]

On each terrace, mix Compost into the sandy clay loam or fill raised beds with Garden Soil. Spread Topsoil to restore areas where erosion has thinned the original soil.^[1]

Mulch is the simplest erosion control on a slope. Brown Shredded Mulch knits together as it settles and resists washing better than loose bark. Spread it after the median last freeze in late March, a few inches deep, and keep it topped up.^[4]

A fall top dressing of Compost on beds and terraces improves the soil over winter and leaves it ready to plant by spring. Mulch over it so it does not wash downhill in winter rain.^[1],[4]

Concrete Sand or Stone Dust Screenings under pavers on a terrace give a level bed, and a compacted stone base beneath them keeps the clay loam from shifting the patio.^[1],[3]

A rain garden works well at the foot of a slope on moderately draining soil. Dig a shallow basin where runoff already gathers, loosen the bottom, and fill it with Garden Soil blended with Compost. Plant its edges with shrubs that tolerate wet roots, and ring the inlet with River Rock so the incoming water does not scour the soil.^[1],[4]

Homes in ZIP 27101 and across Winston-Salem

The Census Bureau's survey finds 12,759 housing units in ZIP 27101, and 39 percent of them are detached single-family houses.^[5]

Winston-Salem as a whole has 115,270 housing units, 62 percent of them detached, with a median build year of 1981.^[5]

The median home in the ZIP was built in 1972. Owners occupy 33 percent of the occupied homes.^[5]

Road crews building for North Carolina's transportation department follow Section 520, Aggregate Base Course, in the January 2024 Standard Specifications for Roads and Structures.^[6]