Driveway & gravel guides

The most important distinction is between well-graded base materials and clean surface materials. Well-graded bases (ABC, CA6, Class 5) contain everything from clay fines up to about 1.5-inch stone. The fines act as a binder — when wet and compacted, they cement the larger particles together into a solid slab. Clean materials (#57, #4, pea gravel) have no fines. They cannot compact into a hard surface by themselves; they need to sit on top of a well-graded base that does the real load-bearing work.

ABC stands for Aggregate Base Course — the universal term, used coast to coast. CA6 is the California state specification, 21AA is the Minnesota specification, Class 5 is the Wisconsin specification. They are all well-graded dense-graded aggregate base; the regional names exist because state DOTs have slightly different gradation bands. For a driveway, pick whichever is available locally — the differences are negligible for non-roadway applications.

The surface materials have their own shorthand. #57 crushed stone is 1–1.5 inch angular crushed rock with no fines. #4 is 2–3 inch angular stone for deep base or drainage. #8 is 3/8–3/4 inch clean crushed rock. Pea gravel is 3/8 inch smooth river gravel. River rock is 1–6 inch smooth rounded stone for decorative drainage. Decomposed granite (DG) is fine particles that pack hard for a natural-looking surface. Each has its own compacted density — 140 lbs/ft³ for ABC, 160 lbs/ft³ for #57, 108 lbs/ft³ for pea gravel — and each density changes the tonnage for the same volume.

Gravel drives the lowest upfront cost: $1.25–$4.50 per square foot installed. But gravel needs regrading every 3–5 years ($200–$500 per service) and full replenishment every 10–15 years ($1.50–$2.50 per sq ft). Over 30 years, gravel costs roughly $15–$25 per square foot total. It also has the highest maintenance — weeds, potholes, and washouts are constant — and the lowest curb appeal of any material.

Asphalt ($3.50–$8.00/sq ft installed) lasts 15–30 years with resealing every 3–5 years ($0.50–$1.00/sq ft per service). Asphalt is dark, smooth, and stays pliable in cold weather (less cracking than concrete). Over 30 years, asphalt costs about $8–$15 per square foot total — significantly less than gravel's annualized cost. The downside is the black surface absorbs heat in summer and can get very hot for bare feet and pets.

Concrete ($4.50–$10.00/sq ft installed) lasts 30–50 years with minimal maintenance — just seal every 5 years if you want to control staining. Over 30 years, concrete costs about $7–$12 per square foot total — the lowest annualized cost of any material. The downside is the hard, unforgiving surface (cracks propagate freely), winter salt damage, and limited color options unless you pay for staining or stamping.

Pavers ($6.00–$15.00/sq ft installed) last 25–50+ years with essentially zero maintenance — replace individual pavers if one breaks, and the whole driveway stays perfect. Curb appeal is the highest of any material. But the initial cost is 2–3x gravel, and installation is slow: pavers must be set individually on a compacted sand bed with edge restraint. Stamped concrete ($7.00–$18.00/sq ft) tries to bridge the gap — concrete patterned to look like stone or brick, with the longevity of concrete and the aesthetics of pavers, but it cannot be patched the way pavers can.

10% waste factor covers compaction settling, spillage during spread, thin spots after the first rain, and the fact that suppliers round delivery up to full cubic yards. This is the minimum — even experienced landscapers use 8–10%. On sloped or curved driveways, use 15%. Projects where you want extra stone for touch-ups and occasional fill-ins should go to 20%. The worst case is ordering exactly the calculated amount and running out 3/4 of the way through compaction — now you pay for a second delivery.

Delivery truck size matters because you do not want to split a small order across two trips. Single-axle dump trucks carry up to about 8 US tons — enough for a single-car driveway. Tandem-axle trucks carry 10–20 tons — the standard delivery size for most two-car driveways. Tri-axle trucks carry 20+ tons but have a higher per-ton cost. If your total gravel is 12 tons, one tandem-axle trip costs less than two single-axle trips at 6 tons each.

Bulk delivery (truck) vs bag delivery (handbags of stone). Bulk is cheaper — $20–$40 per cubic yard delivered — but you need access for a dump truck and a compactor. Bags ($3–$8 per bag) are for small projects and hand-installation, but the cost per cubic yard works out to about $60–$120 — 3–4x bulk. For any driveway larger than a narrow path, bulk delivery is the only sensible option. The calculator shows bag counts anyway, for comparison.

Annual maintenance for a gravel driveway: walk the whole length in spring and look for ruts, potholes, thin spots, and weed growth. Ruts and potholes get filled with fresh top gravel and tamped. Weeds get pulled (not sprayed — herbicide kills soil biology and accelerates washout). Every 3–5 years, rent a plate compactor and recompact the surface; every 10–15 years, add a full top-up of surface gravel to restore depth. These steps cost a few hundred dollars over the lifetime and prevent $2,000+ full replacement.

Almost every US city and county requires a driveway permit — typically $100–$500 depending on your location. The permitting process usually requires a plot plan showing property lines, easements, and the driveway location relative to both. Some areas require erosion control plans for driveways on slopes. Check with your local public works department — the penalty for skipping can be a stop-work order that costs you days of delay and potentially a tear-out requirement.

Project budgeting should include all the extras that DIYers forget. Site prep and subgrade work: $500–$2,000 depending on soil. Old driveway removal: $1–$3/sq ft for concrete, $0.50–$1.50/sq ft for asphalt, $0.50–$1.50/sq ft for old gravel. Permit and inspection: $150–$500. Apron and culvert work at the street: $500–$1,500. Grading and drainage: $400–$1,000. Toggle the 'Additional Work Costs' section on the calculator and all of these get included in your total.