Gravel Delivery in Colorado

The USDA survey reads clay loam at the center points of Denver, Colorado Springs, Lakewood and Arvada. Fort Collins, Thornton and Westminster read loam at their center points, and Aurora reads silt loam. Every one of these eight points is classed well drained. Clay loam packs hard when dry and turns sticky when wet, and clay soils along the Front Range can swell and shrink as their moisture changes. That movement is what cracks slabs and tilts pavers when the base under them is too thin.^[1]

Rock shows up on the geologic map at Colorado Springs, where the center point carries shale and sandstone. Shale weathers into clay, and it is one source of the swelling soils found along the Front Range. Sandstone is sand grains cemented together. Much of the crushed stone and gravel sold along the Front Range is granite, river gravel and other hard rock dug from creek beds and hills, which explains why Colorado loads often carry pink, gray and tan stones in one mix.^[2]

Ground height runs high in every one of these cities. Fort Collins stands at 5,090 feet at its center point and Denver at 5,190 feet. Thornton is at 5,240 feet, Westminster at 5,310 feet, and Aurora and Arvada are each at 5,380 feet. Lakewood's center point stands at 5,550 feet and Colorado Springs's at 5,890 feet. Each of those figures is the height of the ground at one spot in its city.^[3]

The Colorado Department of Transportation names its layer under pavements Aggregate Base Course, Class 6, Section 304, Standard Specifications for Road and Bridge Construction 2025. People around Denver often say Class 6 when they mean a dense, crushed base that packs into a hard layer. When you order for a home job, Road Base and Crushed Concrete fill that role under a drive, a patio or a shed pad.^[4]

Snow and freezing nights drive most of the planning. The weather station used for Arvada averages 75.5 inches of snow a year and logs 168 days at 32 F or colder. Lakewood's station averages 58.0 inches of snow and logs 154 freezing days. Fort Collins averages 51.4 inches of snow and 150 freezing days, and Aurora 49.0 inches and 156 days. The stations for Thornton and Westminster each average 44.8 inches of snow and log 149 freezing days. Denver's station averages 40.7 inches and 150 days, and Colorado Springs's 32.5 inches and 160 days.^[5]

Rain and melt are light by comparison. Lakewood's station averages 17.5 inches of precipitation a year and Arvada's 17.1 inches. Colorado Springs and Fort Collins each average 15.9 inches, Denver 15.8 inches and Aurora 15.4 inches. Thornton and Westminster each average 14.5 inches. A dry yard over clay loam can carry a truck well. The same yard right after a spring snow melts can be greasy on top and rut under one pass.^[5]

Pick the drop spot with that in mind. A paved drive or the street edge where that is allowed is the safe choice most of the year. In winter, have the drive shoveled and leave room on each side for the truck, since plowed banks narrow the lane. A pile of stone can sit through snow with no harm, but soil and mulch left open can freeze into a hard lump, so cover them if a cold night is on the way.^[5]

Check the space above and around the drop. A dump bed needs clear height when it rises, and older neighborhoods in Denver, Boulder and Lakewood have mature trees and low lines over many drives. Alleys can be an easy way to reach a backyard, but some are too narrow or too soft for a heavy truck. On a sloped lot, choose a spot that is level side to side.^[3]

Driveways built for freeze and clay come first. On clay loam like the survey maps at Denver's center point, dig out the soft topsoil and lay a woven fabric on the graded clay. Place Road Base or Crushed Concrete in lifts, packing each one. Finish with 3/4" Crushed Stone, Driveway Gravel or Asphalt Millings. A good crown and a ditch or swale on the low side keep meltwater from soaking the clay under the drive, which is where frost heave starts.^[1]

Low water yards are also common here. Many Front Range owners swap thirsty lawn for stone, mulch and native plants. River Rock and Pea Gravel fill beds and dry creek beds. Decomposed Granite makes firm paths and patios that suit the dry air. 3/8" Crushed Stone and #57 Crushed Stone give a crisp look around shrubs and grasses. Lay fabric under decorative stone so clay does not work up into it over the years.^[5]

Drainage keeps foundations dry. Clay soil around a house can swell when soaked, so roof water should land well away from the walls. A splash pad of River Rock under each downspout, or a French drain filled with Drain Rock or #57 Crushed Stone, moves water off. With 75.5 inches of yearly snow at Arvada's station, a big melt can send a lot of water to the same low corner, and a gravel channel gives it a clean way out.^[5]

Garden beds in clay soil need organic matter. Mix Compost or Garden Soil into the top of a bed, or build a raised bed of Topsoil and Compost so roots stay above the heavy clay. Brown Shredded Mulch or Wood Chips on top slow drying in the sun and wind and keep the soil from cracking. The silt loam at Aurora's center point and the loam at Fort Collins's are easier to dig, but they also do best with a layer of Compost worked in.^[1]

Patios, walkways and play spaces use many of the same materials. Pavers on clay need a thick packed layer of Road Base and a thin bed of Concrete Sand or Stone Dust Screenings. Flagstone set in Decomposed Granite or Mason Sand is a common local look. Wood Chips and Playground Sand suit play areas. Fill Dirt and Fill Sand raise low spots and backfill trenches before the finish layer goes down.^[1]

Ice and snow work add one more use. A covered bin of 3/8" Crushed Stone or Fill Sand by the door gives grit for icy steps and walks, and it is easier on plants than salt.^[5]