Gravel, Rock, Soil and Mulch Delivery in San Jose, CA

Clay Loam at the Center Point

ZIP 95112 sits in Santa Clara County. At the ZIP's center point, the USDA soil survey maps the Urban land-Elpaloalto complex, 0 to 2 percent slopes, and 70 percent of that unit is mapped as paved or built-over ground.^[1]

Elpaloalto is the main soil series in the unit, at 23 percent. Its top mineral layer is clay loam, a blend of sand, silt and clay in which the clay share is high enough to make it sticky when wet and hard when dry.^[1]

The survey rates the soil well drained, so water does not stand in it for long periods. Its hydrologic group is C, slow infiltration, which means rain enters at a slow rate and a heavy shower runs across the surface before much of it goes down.^[1]

Shrink-swell in the top 100 cm rates moderate, at 4.5 percent. Clay loam with that rating grows a little as it soaks up water and shrinks back as it dries, enough to tilt a paver edge or open a crack under a thin slab over several wet and dry cycles.^[1]

The ground at the center point rises 80 feet above sea level, and the map unit's 0 to 2 percent slopes leave it close to flat.^[1],[2]

Flat clay ground gives surface water little reason to move. Grading a yard so it falls gently away from the house, even by a small amount, does more for this soil than almost any material choice.^[1]

A map unit that is 70 percent built over can hide imported fill under lawns and beds. A test hole a spade deep shows whether the top layer is the native clay loam, sticky and brown, or something trucked in during construction, and the answer decides how much digging comes before the base.^[1]

Light Rain and Rare Frost Near Downtown

The nearest NOAA normals station is San Jose, CA, about 1 mile away. It averages 16.1 inches of precipitation in a year and no measurable snow.^[3]

Freezing nights are scarce at the San Jose station. On 2 days in an average year the low drops to 32 F or below. The median first freeze date is December 25, and the median last freeze date is January 2.^[3]

With so little frost, heave from ice is a small concern on this soil. The swelling that matters on clay loam comes from water, so the plan is to keep roof and surface water from soaking the ground right under a slab, a path or a drive.^[1],[3]

A light yearly total also means clay loam spends long stretches dry and hard. Irrigation wets only the top layer unless it runs slowly, and a layer of mulch slows the drying that follows each watering.^[3]

Gardeners with frost-tender plants can give them a layer of mulch ahead of the December 25 median first freeze date at the San Jose station. Gravel and stone work, by contrast, can go ahead in any month, as long as the clay is not soaked when the base is packed.^[3]

Road Base or #57 Crushed Stone Under a Drive

On slow-soaking clay loam, the stone under a drive has two jobs. It has to carry the load, and it has to keep water off the clay. Road Base does the first job well. Its mix of angular stone and fines packs into a dense layer that spreads the weight of a car over the softer ground.^[1]

#57 Crushed Stone does the second job better. It has no fines, so it stays open, lets water pass through and drains it away. On its own it can roll under tires, which is why it works best as a lower drainage layer or as a top coat over a packed base.^[1]

For a drive on this ground, a sound plan uses both. Shape the clay so it falls to one side, lay woven fabric, place a few inches of #57 Crushed Stone, then pack two or three lifts of Road Base above it. Finish with Driveway Gravel for a clean face.^[1]

Fabric matters more on clay than on sand. Wet clay squeezes up into the stone above it under traffic, and once it does, the base loses strength and the surface starts to rut. A woven layer keeps the clay below and the stone above.^[1]

Asphalt Millings are another surface some owners choose for a long drive. They pack hard and shed water once rolled, but they still need the same drained, fabric-backed base on clay loam to stay level.^[1]

Timing the work around the clay helps too. Clay loam that is soaked smears and pumps under a compactor, while clay that is bone dry will not pack at all. The best day to shape the ground is a few days after rain or watering, when a handful squeezed in the fist holds together but does not leave a wet film.^[1]

Beds, Planters and Paths on Clay Loam

Clay loam holds nutrients well but packs hard, and roots struggle in it once it dries. Compost worked into the top layer opens it up and helps water soak in. For a new bed, build it up with Garden Soil so roots start in loose ground.^[1]

Topsoil spread over a lawn area should go on ground that has been loosened first. A hard clay layer under fresh soil can hold water at the boundary after irrigation and leave the grass with shallow roots.^[1]

Brown Shredded Mulch over beds keeps the clay from crusting and slows the loss of water between waterings. Wood Chips suit the ground under trees and along informal paths where a coarser look fits.^[3]

Walkways on clay need a base just as a drive does, only thinner. A course of Road Base under Decomposed Granite or Stone Dust Screenings makes a firm path that stays put after rain.^[1]

Where a downspout empties onto clay, a pad of River Rock and a short Drain Rock trench move that water away from the house, so the clay near the foundation stays at a steadier moisture level through the year.^[1]

One common mistake on clay is mixing sand into it to loosen it. A little sand stirred into clay loam can set up harder than the clay alone. Organic matter does the job instead, so Compost and Garden Soil are the right additions, and sand belongs only under pavers or in a play area.^[1]

Housing in ZIP 95112

Census estimates count 23,628 housing units in ZIP 95112. Across San Jose, the count is 345,066.^[4]

Detached single-family houses make up 25 percent of homes in the ZIP. The citywide share is 51 percent, about twice as high.^[4]

The median home in ZIP 95112 was built in 1969, while the median for San Jose is 1976.^[4]

Owners live in 26 percent of the ZIP's occupied homes.^[4]

Caltrans sets out its requirements for the aggregate layer beneath state roads as Class 2 Aggregate Base, Section 26-1.02B, in its Standard Specifications (2026).^[5]