Gravel, Stone, Soil and Mulch Delivery in Plano, TX

Silty clay over chalk

At the ZIP's center point, the USDA survey maps Austin silty clay, 1 to 3 percent slopes, and Austin soil fills 90 percent of that map unit.^[1]

The soil is a silty clay. It is rated well drained, yet it falls in hydrologic group D, the slowest group for infiltration. The clay sheds water rather than letting it in, and during a storm most rain runs across the surface.^[1]

The shrink-swell rating is moderate, 5.1 percent. Clay with that rating swells noticeably when wet and pulls apart into cracks in a dry summer. Stone surfaces laid straight on it shift with every swing between wet and dry, which is why a compacted base matters so much here.^[1]

The survey records paralithic bedrock at about 29 inches. The USGS geologic map identifies the rock below as Austin Chalk, a marlstone, chalk and claystone unit. Paralithic bedrock is soft, weathered rock that a pick or an excavator bucket can break, and digging deep for a post or a drain may reach it.^[1],[2]

The Austin Chalk dates to the Late Cretaceous.^[2]

Chalk and marl near the surface break down into fine, sticky material when wet. If a dig reaches that layer, keep the spoil out of the base, since it softens under traffic. Use crushed stone or Road Base for anything that has to carry weight.^[1],[2]

Spring storms and mild winters

The NOAA station at Richardson, about 4 miles from the ZIP, averages 41.9 inches of precipitation a year. Much of it falls in strong spring and fall storms, and on slow-draining clay those storms send a lot of water across yards and drives.^[3]

Richardson counts 35 days a year with a low of 32 F or colder. Freezing nights come in short spells, and frost rarely drives deep into the ground, so water and clay movement are bigger worries than frost heave.^[3]

For the Richardson station, the median last spring freeze arrives on March 7. Its median first fall freeze arrives on November 21.^[3]

Storms on clay ground bring a lot of runoff from roofs, drives and the lots next door. Walk the yard during a heavy rain to see where the water flows. The best spot for a drain or a dry creek bed is wherever water already runs.^[1],[3]

Short freezes are harder on soggy clay than on stone. Ground that is saturated before a cold snap can heave a little at the surface, so the drier you keep the soil near walks and drives, the less it moves.^[1],[3]

Keeping water away from the house

On swelling clay, water that collects next to a house is a problem. Grade the soil so it falls away from the walls on every side, and keep downspouts emptying well out into the yard, onto a splash pad of River Rock or into a buried pipe.^[1]

Beds along the foundation should drain away from the house, not toward it. Use Topsoil or Garden Soil to build up low spots, packed so it does not settle into a trough, and cover it with Brown Shredded Mulch to slow evaporation and keep moisture even.^[1],[3]

Where a side yard stays wet after storms, a French drain lined with fabric and filled with Drain Rock carries water to the street or a lower part of the lot. With chalk bedrock at about 29 inches, keep the trench shallow and give the pipe a steady fall.^[1]

Trees and big shrubs pull water out of clay through the summer, and the ground near them can shrink and crack more than open lawn does. Keep stone paths and pads a little away from large trees, or give the base extra depth where it passes over their roots.^[1]

Drives and side yards on shrink-swell clay

A gravel drive or parking pad on silty clay needs a thick, well compacted base to spread the soil's movement. Strip the topsoil, lay a heavy woven fabric over the clay so it cannot pump up into the stone, and compact Road Base or Crushed Concrete in thin lifts.^[1]

Top the drive with Driveway Gravel or 3/4" Crushed Stone, and crown the center so storm water runs to the edges. A Drain Rock trench along the low side keeps water from soaking back under the base.^[1],[3]

Side yards between houses often stay muddy. A path of compacted Road Base topped with #89 Crushed Stone or Walkway Gravel gives a clean, dry walking surface and lets water drain off instead of turning the clay to mud.^[1]

A dry creek bed of River Rock, edged with larger stone, can carry storm runoff across a gentle slope and still look natural in dry weather. Line it with fabric so the clay below does not wash up into the stone.^[1],[2]

Sand alone does a poor job of loosening clay and can leave it even harder. Compost is the better amendment, worked in a little every year.^[1]

Raised beds also give roots more room where chalk bedrock sits within a few feet of the surface. A frame a foot or more tall, filled with Garden Soil, lets vegetables and shrubs grow without hitting rock or sitting in wet clay.^[1]

Lawns and beds on heavy clay

Heavy clay benefits from organic matter. Work Compost into the top few inches of a bed to open the soil and help water soak in. For new beds, build them up with Garden Soil or a blend of Topsoil and Compost, so roots sit above the dense clay.^[1]

With the median last freeze in early March and the median first freeze in late November, the growing season is long. Mulch with Brown Shredded Mulch, Black Shredded Mulch or Red Mulch a few inches deep to keep the soil moist and cool through hot summers.^[3]

Even watering helps clay soil stay more stable. A drip line under mulch delivers water slowly, so it soaks in rather than running off, and it keeps the soil from swinging between soaked and cracked.^[1],[3]

New lawns do best when Topsoil goes down over loosened clay in early spring, after the median last freeze, so the grass roots before the summer heat. Water deeply and less often to push the roots down.^[1],[3]

Homes in ZIP 75023 and across Plano

The Census Bureau's survey records 19,670 housing units in ZIP 75023, and 72 percent are detached single-family houses.^[4]

Plano as a whole has 117,686 housing units, 60 percent of them detached.^[4]

The median home in the ZIP was built in 1985, compared with 1993 for the city. Owners live in 64 percent of the occupied homes in 75023.^[4]

The Texas Department of Transportation specifies Flexible Base, Item 247, for the base under its roads, in its 2024 standard book for highways, streets and bridges.^[5]