Class 5 Gravel

Class 5 gravel starts as crushed limestone or crushed granite, run through a crusher and screened to a dense gradation that spans from about 1 inch down to fine dust and silt. That full range of particle sizes is the defining feature. Unlike washed or clean stone, nothing is screened out. The fines fill the gaps between larger stones, which is what allows the material to compact into a hard, load bearing mass rather than staying loose. The Minnesota DOT spec that gave the material its name sets specific gradation and quality tolerances, and most Upper Midwest suppliers produce to that same gradation even outside Minnesota. It is essentially the regional name for what is called crusher run or dense grade base in other parts of the country, so if you see either term on a spec sheet, they are close cousins describing the same type of compactable, fines included aggregate.

Start by excavating and grading the subgrade, removing topsoil, roots, and soft spots, since class 5 performs only as well as what is under it. Add a woven geotextile fabric over soft or clay heavy soils to keep the base from pumping mud upward over time. Spread class 5 in lifts of 4 to 6 in rather than one thick layer, compacting each lift with a plate compactor or roller before adding the next. Check moisture as you go, since class 5 compacts best slightly damp, not bone dry or saturated. For driveways, crown the surface slightly so water sheds to the sides instead of pooling, since this material does not drain vertically like clean stone. Total compacted depth typically runs 4 to 8 in depending on soil conditions and expected load, with heavier vehicle traffic justifying the deeper end of that range.

Compared with class 1 gravel. Class 1 is a finer, more tightly specified gradation used for higher load applications and finished road surfacing, while class 5 is the coarser, more general purpose base material. Class 5 is the default choice for driveways and general base work, class 1 gets specified when a spec calls for a smoother finished surface or higher strength requirement.

Compared with crushed limestone versus crushed granite class 5. Limestone class 5 tends to compact slightly harder and binds well due to its softer stone chemistry, with a lighter tan or gray color, while granite class 5 is harder wearing but can compact a touch looser and often shows a darker gray or speckled color. Regional supply usually decides which one you get.

How much class 5 gravel do I need. Multiply the area in square feet by your desired depth in feet, then divide by 27 to get cubic yards. For a typical 3 in driveway base, figure roughly 100 to 110 sq ft of coverage per cubic yard, or about 160 to 170 sq ft at 2 in. For tonnage, multiply cubic yards by 1.3 to 1.45 to account for typical density. Always round up slightly to cover compaction settling and uneven subgrade.

How class 5 gravel is sold and delivered. Class 5 is sold by the cubic yard or by the ton and delivered in bulk by dump truck, dropped in a driveway, staging area, or directly into a prepped excavation. Because it is dense and heavy, larger orders may require multiple truckloads or a tandem axle delivery. Confirm truck access and dump location ahead of time, since bulk piles need room to spread and compact in lifts.