Gravel, Sand, Soil and Mulch Delivery in Houston, TX

Heavy Rain Landing on Clay

Houston-Port, TX, about 5 miles away, is the closest NOAA normals station, and it averages 54.1 inches of precipitation a year. Snowfall there averages 0.0 inches. Every bit of that water arrives as rain, often in hard downpours, and on clay ground it has nowhere quick to go.^[1]

Freezing nights are rare. The station logs only 5 days a year with a low of 32 F or colder. Its median last spring freeze falls on February 2, and its median first fall freeze is December 25. Cold weather is not what breaks a base here, so the design effort goes almost entirely into shedding water.^[1]

For a buyer that means sloping every surface, building beds up rather than down, and giving water a gravel path out. Drain Rock in a trench, River Rock in a swale and a crowned Driveway Gravel surface all serve the same goal: keep rain moving instead of letting it sit on clay.^[1]

Outdoor building and planting can carry on through most of the winter, since a freezing night is such a rare event at the Houston-Port station.^[1]

Clay Under the Pavement

The USDA soil survey labels the ZIP's center point Urban land, with 100 percent of the map unit counted as paved or built over. At a downtown point like this, streets and building pads have replaced the natural surface entirely.^[2]

Beneath the made ground, the state geologic map shows the Beaumont Formation, areas predominantly clay, at the center point. The unit is clay and silt of Pleistocene age. Clay and silt hold water and soften when soaked, so any base built over them needs fabric underneath and a thicker layer of stone than it would need on sand.^[3]

A fill job on clay works better with Fill Sand or Fill Dirt brought in and packed in layers than with clay dug from somewhere else on the site. Native clay packs hard when dry but turns to paste in a storm, which is the last thing anyone wants under a slab or a patio.^[3]

Clay can also move. It can shrink and crack as it dries in a hot spell and swell again when the rain returns. That slow movement can crack a slab or tilt a paver edge, so a thick, packed layer of stone between the clay and the surface works as a buffer.^[3]

Downtown Living in ZIP 77002

There are 9,439 housing units in ZIP 77002, according to the Census Bureau's survey. Just 2 percent are detached single-family houses, while across Houston the share is 43 percent of 1,040,576 units. The ZIP's median home was built in 2010, much newer than the city's median year of 1982. Owners occupy 8 percent of the ZIP's occupied homes, so most residents rent.^[4]

Projects in a ZIP like that lean toward building grounds, courtyards, rooftop and podium gardens, and commercial landscape beds. Garden Soil and Compost fill planters, and Brown Shredded Mulch or Red Mulch dresses the beds. Construction sites nearby use Fill Sand, Crushed Concrete and Road Base for pads and temporary drives.^[4]

Commercial beds take a beating from foot traffic, heat thrown off glass and concrete, and storms that dump water fast. A bed raised a little above the pavement around it, filled with Garden Soil and topped with Brown Shredded Mulch, drains through those storms and keeps its shape.^[1]

Raised Beds Above Slow Ground

On clay and silt like the Beaumont Formation, a garden dug straight into the ground can sit waterlogged for days after a storm. Raising the bed solves it. A frame filled with Garden Soil, or Topsoil blended with Compost, keeps roots above the wet layer and drains freely through the sides.^[3]

Freezes are uncommon, with a median first fall freeze on December 25 at the nearby station, so beds here grow through most of the winter. Top them with Black Shredded Mulch or Wood Chips to hold moisture through hot spells and to keep heavy rain from splashing soil onto the leaves.^[1]

Paths between beds should drain as well as the beds do. Pea Gravel is soft underfoot but drifts, while #89 Crushed Stone or Stone Dust Screenings packs firmer and stays flat. Either one sits best on fabric so the clay below does not swallow it over a few rainy seasons.^[1]

Crushed Concrete or Road Base

Road Base and Crushed Concrete each make a firm, packed base, and the choice between them comes down to the job. Road Base is crushed stone mixed with fines in a spread of sizes, so it packs into a tight, smooth layer that sheds water. Crushed Concrete is recycled slab and curb broken into a similar spread. It packs nearly as well, weighs a little less, and reuses material that would otherwise be thrown away. Over the clay and silt mapped under the center point, either one needs fabric beneath it.^[3]

For a driveway with daily traffic, Road Base packs denser and holds an edge longer. For a temporary construction pad, a shed floor or a parking strip behind a building, Crushed Concrete does the job well. With 54.1 inches of yearly rain at the station, keep either base crowned so storms run off instead of soaking through to the clay.^[1]

A Driveway Built for Clay and Downpours

A gravel drive over clay starts with stripping the soft topsoil and packing the subgrade, then laying a heavy woven fabric. Fabric keeps the stone from pushing down into wet clay, which is how gravel drives on this kind of ground slowly disappear.^[3]

A lower course of 1-1/2" Crushed Gravel or #4 Crushed Stone gives water an open layer to move through. Road Base packed in thin lifts goes on top and forms a dense driving course, and a final dressing of 3/4" Crushed Stone or Driveway Gravel gives grip. Crown the surface so the 54.1 inches of yearly rain at the station runs off to the sides.^[1]

The Texas Department of Transportation names Flexible Base, Item 247, in its Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Contractors working on state jobs build to that item. On a private drive, the job is simpler: good fabric, good packing, and a surface that never lets water pool.^[5]

The edges of a drive and the ends of a culvert erode first in a hard rain. A band of Riprap at a culvert outlet, or a lining of River Rock along a side ditch, slows the water and holds the soil in place. A gravel shoulder of #57 Crushed Stone along the edge of the drive does the same job on a smaller scale.^[1]