In short, a residential asphalt driveway in Australia should be 25–30mm of compacted hot mix over 75–100mm of compacted road base. Heavier vehicles (caravans, trailers, work utes) need 40mm of asphalt over 150mm of base. Commercial driveways and carparks run 50–75mm asphalt. Here’s the longer story, with the spec we put on every BWB quote.
Asphalt driveway thickness: what’s standard in Australia?
The Australian standard for residential asphalt driveways (Austroads AGPT-04F) calls for 25mm minimum compacted asphalt over 100mm of compacted granular base. In practice, that’s the floor — proper jobs go slightly thicker for durability.
Quick reference: asphalt thickness by use case
| Use case | Asphalt depth (compacted) | Base depth | Total pavement |
|---|---|---|---|
| Light residential (car + occasional ute) | 25mm | 100mm | 125mm |
| Standard residential (2 cars, caravan) | 30mm | 100mm | 130mm |
| Heavy residential (work ute + trailer + boat) | 40mm | 150mm | 190mm |
| Rural acreage driveway | 30mm | 150mm | 180mm |
| Light commercial / retail carpark | 50mm | 150mm | 200mm |
| Heavy commercial / truck access | 75mm (2 lifts) | 200mm | 275mm |
| Industrial / B-double | 100mm+ (2–3 lifts) | 300mm | 400mm |
These are compacted depths. Loose mix compacts to roughly 80% of laid thickness, so a 30mm compacted layer is laid at about 38mm pre-roll.
Why thickness matters more than people think
A driveway thinner than 25mm doesn’t fail because it’s too thin to drive on. It fails because it has no thermal mass — hot Aussie sun softens it faster, cold winter days make it brittle. 20mm asphalt driveways start cracking within 18 months. We pull up at least one a year on the Coast.
Does thinner asphalt save money?
Short term, yes. A 20mm overlay costs about 25% less than 30mm. Long term, it’s the most expensive mistake on the driveway. You pay again for a full strip and replace in 2–3 years instead of getting 20+ years out of the original job.
How can I tell how thick my existing driveway is?
Dig a small core (or get us to). Easiest spot is along an edge where the asphalt meets a path or kerb. Measure from the top of the asphalt to the top of the base — that’s your wearing course thickness.
Base depth: the thing most quotes get wrong
Asphalt thickness gets the attention. Base depth matters more. A 30mm asphalt slab on 50mm of base will fail. A 25mm asphalt slab on 150mm of properly compacted road base will outlive both.
The base spreads the wheel load. Without enough base, every car tyre punches a localised stress into the subgrade, the subgrade deforms, and the asphalt cracks following the deformation.
What goes in the base?
Compacted DGB20 or similar road base — angular crushed rock, well-graded from dust up to 20mm. Compacted in 75mm lifts with a vibrating roller. On reactive clay or boggy ground, we add geotextile fabric between subgrade and base.
How much base do I need over clay?
On the reactive clays west of the Coast (out toward Wyong Creek, Yarramalong, Mangrove Mountain), we use 150mm minimum, often 200mm. Geotextile fabric mandatory. Skimp here and the asphalt will pump within two years.
Single layer vs two lifts: when do you need both?
For residential under 40mm, asphalt is laid in a single lift. Above 40mm you split it: a binder course (coarser mix, deeper) plus a wearing course (finer mix, surface).
Example for a heavy residential 40mm spec:
- 25mm AC14 binder course
- 15mm AC10 wearing course
The binder gives you structure, the wearing course gives you the finish. Single-lift 40mm jobs are possible but harder to compact evenly — the centre of the slab cools slower than the surface and edges, and you get density variation.
Does my driveway need two lifts?
Only if total asphalt depth is 50mm+. For a standard 30mm residential driveway, single lift is correct.
How thick should I go for a caravan or boat trailer?
If you’re parking a caravan, boat, or work trailer regularly — especially with a jockey wheel or stand on a single point — go 40mm asphalt over 150mm base. Point loads from a jockey wheel can dimple thinner asphalt within a year, particularly in summer when the surface is warm.
Better alternatives if budget allows:
- 40mm asphalt + a 600x600mm concrete pad where the jockey wheel sits
- Permanent concrete strips under the trailer wheels, asphalt either side
- Full concrete in the trailer parking zone, asphalt for the rest
Will a caravan damage a 25mm driveway?
Yes, eventually. The jockey wheel and the stabiliser legs concentrate weight on a 50mm circle. After 12 months of summers, you’ll see dimples 5–10mm deep. Not catastrophic, but ugly.
Commercial vs residential: why carparks are thicker
Commercial carpark spec on the Coast typically runs:
- Cars only: 40–50mm asphalt over 150mm base
- Light delivery trucks: 60–75mm asphalt over 200mm base
- B-double access: 100–125mm asphalt over 300mm base, often a stabilised base layer underneath
The wheel loads scale up fast. A loaded delivery truck puts 30 kN per wheel through the pavement, vs 6 kN for a family car. Five times the load needs more than five times the pavement — closer to ten.
Why is residential not just "the cheap version of commercial"?
Different design philosophy. Residential is designed for a couple of cars and the occasional service van. Commercial is designed for daily heavy vehicle traffic. The materials are similar; the geometry isn’t.
What about Asphalt Concrete mix size (AC7, AC10, AC14, AC20)?
The number after AC is the nominal maximum aggregate size in millimetres:
- AC7 — fine surface mix, used for thin overlays (15–20mm) and patching
- AC10 — standard residential driveway mix, 25–30mm
- AC14 — heavier residential and light commercial, 35–50mm
- AC20 — base course for heavy commercial, 50mm+
AC10 is what 90% of Central Coast driveways get. It compacts well at 25–30mm, holds a tight surface, and resists ravelling. AC14 we use on steep driveways and where heavy utes park regularly.
For deeper detail on mix design, see Austroads pavement guidelines — they’re the technical authority for Australian road and pavement design.
How thickness affects price
Going from 25mm to 30mm asphalt adds roughly $3–$5 per m². Going from 30mm to 40mm adds another $7–$10 per m². Base depth increases cost more — every extra 50mm of road base is around $8–$12 per m².
| Spec | Cost per m² 2026 |
|---|---|
| 25mm asphalt + 75mm base | $65–$80 |
| 30mm asphalt + 100mm base | $72–$92 |
| 40mm asphalt + 150mm base | $88–$110 |
| 50mm asphalt + 150mm base | $95–$125 |
For full pricing context, see our 2026 asphalt driveway cost guide.
Common thickness shortcuts that cause failure
- Laying 20mm "to save money" — fails within 24 months
- Skipping the base course — direct to subgrade, pumping starts within a year
- Thin base under heavy use — 50mm base under 30mm asphalt; rutting in 18 months
- No geotextile on clay — base pumps up through asphalt, surface heaves
- Single lift 50mm pour — uneven compaction, soft spots, rapid wear
If a quote doesn’t spell out asphalt depth AND base depth in millimetres, ring the contractor before signing. "Asphalt driveway laid" isn’t a spec.
FAQs
How thick should an asphalt driveway be in Australia?
25–30mm of compacted hot mix asphalt over 75–100mm of compacted road base for a standard residential driveway. Heavier use (caravans, work trailers, regular ute traffic) bumps to 40mm asphalt over 150mm base.
Is 25mm asphalt thick enough for a driveway?
For light residential use (two family cars, occasional service van), yes — 25mm of AC10 over a properly compacted 100mm base will give you 20+ years. For anything heavier, go 30–40mm.
How thick is a commercial asphalt carpark?
40–75mm depending on vehicle type. Cars-only carparks run 40–50mm asphalt over 150mm base. Truck-access carparks need 60–75mm in two lifts over 200mm base.
How thick is council road asphalt?
Australian council roads typically have 40–80mm of asphalt over 200–300mm of stabilised base. Major arterials run thicker still — 100–150mm over engineered subgrade. Far heavier than any driveway.
Want a spec that’s right for your driveway — not just the cheapest quote? Send through the quote form and Glenn or one of the crew will come out, look at the soil, the slope, and your usage, and write up a proper spec. No guesswork.
