Why a Driveway Glossary Matters
A new driveway is one of the biggest curb-appeal investments you can make, yet the industry is packed with jargon. If you’ve ever nodded along while a contractor mentioned “sub-base,” “spalling,” or “MC-300,” this driveway glossary is for you. Understanding the lingo helps you:
- Compare apples-to-apples quotes
- Ask the right questions before work starts
- Avoid surprise up-charges
- Spot red flags that signal low-quality work
Bookmark this page and pull it up during your next contractor walk-through—you’ll sound like a pro and protect your budget.
Design & Layout Terms
Driveway Apron
The first 8–15 ft of driveway that meets the public street. City codes often control apron thickness, rebar, and slope. If yours is crumbling, you may need a separate city permit to replace it.
Swale
A shallow grass or concrete trench that channels storm water away from the garage and into the street drain. Add a swale if your lot is flat or slopes toward the house.
Turnaround Pad
A widened 18–20 ft diameter pad at the end of a long driveway so you can back into the street nose-first. Planning one now saves future landscaping headaches.
Bellmouth / Flare
The widened entrance that funnels cars smoothly off the street. Standard flare adds 2 ft of width on each side; decorative stamped borders can hide the flare while keeping function.
Material Types Explained
Asphalt (Bituminous Concrete)
Hot-mix asphalt (HMA) is stone, sand, and liquid asphalt cement heated to 300 °F and compacted. Ask for “9.5 mm Superpave” for residential driveways; it’s smoother and tighter than commercial mixes.
Portland Cement Concrete (PCC)
Gray slabs that last 30–40 years. Specify 4,000 psi minimum, 5–6% air entrainment for freeze-thaw zones, and ½-inch rebar on 18-inch centers. Fiber mesh alone is cheaper but won’t stop settling cracks.
Stamped / Colored Concrete
After the pour, contractors press polyurethane mats and add color hardeners. Seal every two years to stop “efflorescence,” the white powdery bloom that dulls colors.
Interlocking Pavers
Concrete or clay bricks that lock via chamfered edges and joint sand. Look for ASTM C936 spec: 8,000 psi compression strength, less than 5% absorption. Always insist on edge restraints so the perimeter doesn’t creep.
Chip Seal
Emulsion sprayed over compacted base, then coated with pea gravel and rolled. Popular in rural areas; adds skid resistance but needs a fresh top every 5–7 years.
Permeable Paver Systems
Open joints let rainwater drain through to a crushed-stone reservoir below. Great for storm-water credits, but you must vacuum the surface yearly to prevent clogs.
Base & Sub-Base Lingo
Sub-Grade
The native soil after excavation. A proof-roll test (driving a loaded truck slowly) reveals soft spots that need under-cutting and re-compaction.
Geotextile Fabric
Woven or non-woven sheet laid on sub-grade to keep stone and soil from mixing—especially critical on clay soils. Ask for AASHTO M288 Class 2.
Base Layer
4–8 in. of dense-graded aggregate (¾-inch minus) compacted to 98% Standard Proctor. Thicker isn’t always better; match thickness to local frost depth.
Sub-Base
Additional 4–6 in. of open-graded stone (1½-inch clean) used in freeze zones or poor soils. Provides drainage and acts as a frost barrier.
Compaction
Mechanical tamping with a plate compactor or roller in 4-inch “lifts.” Request a density test ticket; reputable crews keep a nuclear gauge on site.
Drainage & Slope Terms
Crown
A 2% hump in the center so water drains to both edges. Critical on gravel drives to prevent wash-boarding.
Cross-Slope
Single-direction tilt (1–2%) toward the yard or street. Choose cross-slope if a crown would create a high pivot point that scrapes low cars.
French Drain
Perforated pipe buried in stone along the driveway edge. Daylights to a pop-up emitter 10 ft downhill—perfect for soggy side yards.
Trench Drain / Channel Drain
Surface grate with embedded trough across the apron or garage opening. Stainless edges resist rust from snow-melt salts.
Surface Defects & Repair Vocabulary
Spalling
Top ⅛–¼ in. of concrete peels away, usually from freeze-thaw plus de-icing salts. Patch with polymer-modified cement; seal afterward.
Raveling
Loose stones on asphalt indicate oxidized binder. A fog seal (emulsion + sand) buys 2–3 years; plan for a 1-inch overlay soon.
Alligator Cracking
Interlaced cracks resembling reptile skin—sign of base failure. Requires full-depth removal and patch; surface sealers won’t help.
Pumping
Water squirts up through joints when you drive over them. Means fines are migrating; install edge drains and reseal joints.
Settlement / Subsidence
Sunken areas near utilities or tree roots. Foam jacking (polyurethane injection) lifts slabs in hours vs. days for mudjacking.
Installation & Cure Phrases
Edge Restraint
Concrete mow-strip or plastic spikes that keep pavers from spreading. Skipping this step voids most paver warranties.
Control Joint
Sawn or tooled groove ¼ the slab depth to guide cracks. Space joints at 2–3 × slab thickness (in feet). Seal joints with polyurethane to stop water.
Expansion Joint
½-inch fiberboard separating driveway from garage floor or street. Allows movement without cracking adjacent concrete.
Cure Time
Concrete reaches 70% strength in 7 days; keep cars off for at least that long. Asphalt cools enough for foot traffic in 24 h, but wait 3–5 days for heavy trucks.
Saw-Cut Timing
Joint cutting within 4–12 h of pour prevents random cracks. Too early = raveling edges; too late = cracks already started.
Sealers, Additives & Finishes
Acrylic Sealer
Fast-drying, UV-stable, but needs re-coat every 2–3 years. Ideal for stamped concrete with color.
Penetrating Silane-Siloxane
Lines the pores without changing appearance; 10-year life on plain gray concrete. Salt-shield versions are worth the extra $0.25/sq ft in northern states.
Coal-Tar vs. Asphalt Emulsion Sealer
Coal-tar resists fuel spills but smells strong and is banned in some cities. Asphalt emulsion is eco-friendlier but needs yearly touch-ups under drip lines.
Fiber Mesh / Micro-Rebar
Alkali-resistant polypropylene fibers reduce hairline cracks but don’t replace structural steel. Ask for 1.5 lb/cu yd dosage.
Cost Factors Decoded
Per-Square-Foot Pricing
National averages: asphalt $3–5, plain concrete $6–9, pavers $12–18, permeable $15–22. Add 30% for demo of old pavement.
Mobilization Fee
Flat charge ($300–500) for bringing rollers, trucks, and crew. Smaller jobs (< 1,000 sq ft) feel the sting—team up with neighbors to share a pour.
Change Order
Written amendment for extras (color upgrade, drain addition). Insist on a unit-price list up front; it curbs sticker shock.
Contingency
Keep 10% of the contract value unspent until final walk-through. Use it to negotiate touch-ups like small pop-outs or joint overfill.
Maintenance Cheat Sheet
- Seal asphalt every 3 years; concrete every 5.
- Fill cracks wider than ¼ inch before sealing.
- Switch to calcium magnesium acetate (CMA) ice-melt to cut spalling risk.
- Keep drip edges swept; oil softens asphalt binder within weeks.
- Run a hose along the perimeter each spring—ponding water signals drain clogs.
Driveway Glossary FAQ
Portland cement concrete (4,000 psi, properly cured) lasts 30–40 years with minimal upkeep. Interlocking pavers edge ahead in flexibility—they can reset individual units if tree roots lift the surface.
For light vehicles on good soil: 4 in. of dense-graded base. Add 4 in. of open-graded sub-base if you have clay or freeze-thaw cycles. Commercial trucks or RVs need a 6–8 in. base plus 6 in. sub-base.
Yes—clean, crack-fill, and apply with a squeegee on a 50–80 °F day. Buy a quality commercial-grade sealer; big-box store “fill and seal” products often contain excess water and wear off in one season.
Hairline surface cracks (< ⅛ in.) are cosmetic. Seal them to prevent water entry. Cracks wider than ¼ in., especially with vertical displacement, indicate base issues—schedule a pro evaluation before winter.