Gravel Delivery in Iowa

The soil readings in our Iowa cities suit builders. The USDA survey classes the top layer at the center point of Cedar Rapids as loam, well drained. Johnston's center point reads the same: loam, well drained. Loam is a balanced mix of sand, silt and clay. It holds enough water for roots and still lets the excess soak away, and when compacted it makes a fair subgrade for a stone drive.^[1]

Ground height differs between the three cities. The center point of Johnston stands 910 feet above sea level and Cedar Rapids reads 730 feet. Davenport's center point is the lowest of the group at 560 feet. These are single spots, and a yard on a slope or in a creek bottom may sit well above or below them, so walk your own lot after a rain and see where water collects before you lay out a drive or a bed.^[2]

A load of crushed stone starts as solid bedrock that is drilled, blasted and run through crushers and screens. Every piece comes out angular, with fresh, rough faces that grip each other once packed. That grip is why crushed stone, and not round gravel, goes under anything that carries a car. The sizes run from #4 Crushed Stone and 1-1/2" Crushed Gravel at the coarse end down to #89 Crushed Stone and 3/8" Crushed Stone at the fine end.^[1]

Round stone forms another way. River Rock and Pea Gravel come from water-worn deposits, where current and time have smoothed every edge. They look good in a bed and drain freely, but they roll under a tire and spread out. On well drained loam like the survey reads at the Johnston center point, a bed of River Rock stays tidy for years because the ground beneath it does not stay soggy.^[1]

Mixed products fill out a load list. Road Base and Driveway Gravel combine crushed stone with fine grit that fills the gaps and sets up hard. Stone Dust Screenings are that grit alone, used as a bed for pavers. Crushed Concrete and Asphalt Millings are recycled from old pavement and pack into a firm surface. Topsoil, Garden Soil, Compost and Fill Dirt cover the soil side, and the loam at the Cedar Rapids center point mixes well with any of them.^[1]

Cold shapes the delivery calendar more than rain does. The weather station used for Johnston logs 135 days a year at 32 F or colder, and the one for Cedar Rapids logs 134. Davenport's station records 118 days. Frozen ground is hard enough to carry a truck, but a load of stone or soil dropped on frozen ground can freeze into a solid block, and soil cannot be spread or compacted well until it thaws.^[3]

Snow adds its own planning. The station for Johnston averages 38.0 inches of snow a year and the one for Cedar Rapids 34.3 inches. Clear the drop spot and the path in before the truck arrives, and mark the edges of the driveway so the driver can see them. A plow ridge along the curb can hide the line between pavement and lawn, and a heavy truck on a soft lawn edge leaves deep ruts.^[3]

Spring thaw is the softest time of year. As frost leaves the ground, the top layer can stay wet even on well drained loam. Precipitation at the Cedar Rapids and Davenport stations averages 38.8 inches a year each, and Johnston's station reads 36.2 inches. After a long soaking rain, a paved drive is a far better drop spot than a lawn, and a tarp under the pile protects the grass beneath it.^[3]

Check the route as you would for any large truck. Low branches, overhead lines, mailboxes, narrow gates and tight turns can all limit where the driver can go. A raised dump bed needs open space above it, so a spot under a big tree or near wires may not work. On a rural lot, tell us if the lane is soft or long, so the driver knows what to expect.^[3]

Gravel driveways are the most common order, and the long winters set the design. With 134 days at 32 F or colder at the Cedar Rapids station, water that sits in a base will freeze and lift it. Build on graded loam with a thick layer of Road Base compacted in lifts, then a top of #57 Crushed Stone or Driveway Gravel. Crown the surface so melt water runs off, and leave room along the edges for plowed snow.^[3]

Drainage around the house is the next most common job. Snowmelt and spring rain run toward foundations, and a French drain filled with Drain Rock or #57 Crushed Stone and wrapped in fabric gives that water a way out. A dry well of clean stone at each downspout takes the flow from the roof. Riprap protects a ditch bank or the end of a culvert, where fast water can cut into the soil.^[3]

Garden beds on loam need less work than most. Loam already holds water and air well, so a few inches of Garden Soil or Compost worked into the top is enough for most new beds. Cover it with Brown Shredded Mulch, Black Shredded Mulch or Red Mulch to hold moisture through summer and to protect roots in winter. Topsoil finishes a graded yard before seed or sod, and Fill Dirt builds up low spots underneath.^[1]

Patios and walks follow the same layering as drives, on a smaller scale. Pavers sit on compacted Road Base with a thin bed of Concrete Sand or Stone Dust Screenings. Freezes push up pavers set on a thin or wet base, so give a patio a full base and a slope away from the house. A path can use Walkway Gravel, Decomposed Granite or Pea Gravel between edging. Mason Sand works for setting stone and for joints.^[3]

Farm and acreage jobs use the heavy grades. Crushed Concrete and Asphalt Millings make a firm, dark surface for machine sheds and long lanes. #4 Crushed Stone and Railroad Ballast form a stable first layer over soft spots before lighter stone goes on top. Wood Chips cover play areas and paths under trees, and Playground Sand fills a sandbox. Fill Sand levels a pad before a slab is poured.^[2]

Winter care is part of any gravel project here. Plows and snow blowers scrape the top stone off a drive and throw it into the lawn, so set the blade a little high and rake the stone back in spring. With 34.3 inches of yearly snow at the Cedar Rapids station, a stone edge or a row of timbers along the drive keeps the gravel where it belongs and shows the plow where the surface ends.^[3]