Concrete Driveways: How They’re Built, What Lasts, and What to Specify
A concrete driveway is a simple thing built out of six decisions: how deep the excavation goes, how much basecourse sits under it and how well it is compacted, how thick the slab is, what strength the concrete is, where the reinforcement sits, and where the joints go. Get those right and you have a surface that lasts 25–35 years with almost no attention.
Almost every driveway that fails early fails on one of those six, and five of them are invisible once the concrete is down. That is why two quotes for the same driveway can differ by thousands — they are specifying different jobs, and the difference is buried.
This guide explains what each part of the specification means and what changes if you alter it, so a quote reads as a description of a job rather than a number. Costs are summarised in one table below, with links to the detailed breakdowns.
The Part You Never See Is the Part That Matters
Concrete is strong in compression and weak in tension. Sit it on ground that supports it evenly and it will carry a vehicle indefinitely. Sit it on ground with a soft spot and the slab has to span that gap — a job it is bad at — so it bends slightly and cracks.
That single fact explains most driveway failure. The slab is rarely the problem; the support underneath it is. A 100 mm slab on a properly compacted basecourse outperforms a 150 mm slab on a poorly prepared one, every time.
Which is why the order of importance on a quote runs roughly: excavation and base preparation first, then slab thickness, then reinforcement position, then joint layout, then concrete strength, then the finish. Most homeowners read that list in reverse, and most cheap quotes are cheap at the top of it.
The Specification, Line by Line
What each item means, the usual answer for a residential driveway in New Zealand, and what happens if it is skimped.
| Item | Standard for a residential driveway | What happens if it is cut |
|---|---|---|
| Excavation depth | Deep enough to remove soft and organic material and fit the basecourse plus slab at the right finished level | Slab sits on topsoil or soft fill and settles unevenly |
| Basecourse | Compacted crushed hardfill, depth suited to the ground and load, compacted in layers | The single biggest cause of early cracking and settlement |
| Slab thickness | 100 mm for cars; 125–150 mm for boats, campervans, trailers or work vehicles | A thin slab cracks under vehicle loads within a few years |
| Concrete strength | Typically 20–25 MPa for residential work | Weaker surface, more prone to wear and spalling |
| Reinforcement | Steel mesh to AS/NZS 4671, on chairs, within the slab depth | Mesh on the base does almost nothing; mesh near the surface rusts and splits the slab |
| Control joints | Cut or tooled at planned spacings | The slab chooses its own crack lines, usually diagonally across the middle |
| Falls and drainage | Minimum crossfall around 1–2%, channel or sump where needed | Water pools, which drives moss, staining and freeze-thaw damage |
| Curing | Curing compound, covers or damp curing to retain moisture | Weak, dusty surface that spalls within a few years |
The Specification Decisions Worth Understanding
Thickness: 100 or 150 mm?
A residential driveway carrying cars is 100 mm. Go to 125–150 mm if you will park a boat, campervan, trailer, or a work truck on it, or if a concrete or delivery truck will use it. The extra 50 mm is a real cost increase and should be an explicit line on the quote — it is the most common place for an assumption to be wrong.
Strength: what MPa means
MPa is the compressive strength the concrete reaches at 28 days. Residential driveways are typically 20–25 MPa. Higher strength mixes exist and are used for commercial and industrial work. A higher number is not automatically better value on a driveway — strength does not compensate for a poor base.
Reinforcement: position beats quantity
Steel mesh controls cracking by holding the slab together once it cracks. To do that it has to be within the slab, held up on chairs. Mesh lying on the hardfill contributes almost nothing, and mesh sitting too close to the surface eventually corrodes and splits the concrete from inside — which is what rust staining along a crack line means.
Joints: deciding where it cracks
Concrete shrinks as it cures and it will crack. Control joints create a planned weak line so cracking happens there, in a straight line you do not notice, rather than randomly. Joints too far apart, or missing, and the slab picks its own route. Joints should also be kept sealed so water cannot get underneath.
Drainage: designed in, not added later
A crossfall of around 1–2% keeps water moving off the surface. Where a driveway falls towards a garage or a boundary you need a channel or a sump, and that has to be set out before the pour. Retrofitting drainage into a finished slab is expensive and never as tidy.
Curing: not the same as drying
Concrete gains strength through a chemical reaction with water, not by drying out. Losing moisture too early gives you a weak, dusty surface that spalls later regardless of the mix. This is the cheapest stage to skip and one of the most consequential, particularly in wind or frost.
Finishes: What Each One Costs and Does
The finish sits on top of an identical slab. It changes appearance, grip and maintenance — not structure.
| Finish | Cost/m² | Grip | Maintenance |
|---|---|---|---|
| Broom finish | $100–$180 | Good | Wash and reseal occasionally. Shows oil and tyre marks clearly. |
| Exposed aggregate | $150–$230 | Excellent | Reseal every 1–3 years with a topical sealer. Hides marks well. |
| Coloured | $150–$220 | Good | Sealing is essential — pigment fades under UV without it. |
| Stamped | $150–$220 | Varies with pattern | Reseal regularly. Can be slippery if sealed high-gloss. |
| Honed or polished | Above exposed aggregate | Lower when wet | Penetrating sealer. Ground back after curing, so it is a separate stage. |
Ranges are NZ planning estimates for 2026 and assume the same base preparation underneath. For full cost breakdowns see the detailed guides linked below.
What a Concrete Driveway Costs
In short: $100–$180 per square metre for a plain broom finish and $150–$230/m² for exposed aggregate or a coloured finish, which puts a typical 50–100 m² driveway somewhere around $3,750–$15,000 all up.
That range is wide because site conditions dominate it. Access for a concrete truck, how much excavation and spoil removal is required, basecourse depth for the ground you have, drainage work, and whether an old driveway has to come out first will all move the figure more than the choice of finish does.
We have gone into the numbers properly rather than repeating them here. For a full breakdown see how much it costs to concrete a driveway in NZ and the price of a concrete driveway. For exposed aggregate specifically, aggregate driveway cost. For the cheaper alternatives, cheap driveway options. And if you are weighing concrete against asphalt, asphalt vs concrete.
How Long It Lasts, and What Shortens It
A properly built concrete driveway gives 25–35 years, and often considerably longer. Concrete pavers can reach 30–50 years with joint maintenance. Asphalt is more like 15–20 years, and chip seal 10–15.
What shortens a concrete driveway is almost always one of a short list. An under-prepared base settles and the slab cracks to follow it. A slab that is too thin for what parks on it cracks under load. Badly positioned mesh either does nothing or corrodes and splits the slab. Missing or widely spaced joints let the slab crack wherever it likes. Water that pools, or gets into unsealed joints and freezes, causes surface damage and edge failure.
Notice that none of those is the concrete. In New Zealand, and particularly in the South Island where overnight temperatures drop below zero through winter, water and the base are what kill driveways. Keeping joints sealed, keeping water moving off the surface, and sealing the concrete are the three things that extend a driveway’s life for very little money.
When a driveway does start to go, the choice is repair, resurface or replace, and that depends on whether the slab is still moving. Resurfacing a sound slab costs roughly $70–$180/m² and adds 8–15 years; replacement is $130–$260/m² and resets the clock. We work through how to tell which one you need in resurfacing a concrete driveway and concrete repairs.
Before Work Starts
Two things that catch people out regardless of where in New Zealand they are.
Council approval for the vehicle crossing
Where the driveway meets the road you are working on council land, and forming, widening or reinstating that crossing needs written approval before work starts. Requirements and processes differ between councils, so confirm with yours early — approval can take weeks, and unapproved work may have to be removed and redone at your cost.
Impervious surface limits
Many district plans cap how much of a site can be covered in hard surface as a permitted activity — in Christchurch it is up to 65%. On a smaller section with a house, garage, patio and driveway, that ceiling arrives sooner than expected, and exceeding it can mean resource consent. Permeable paving is one way to stay inside it.
Weather and timing
Concrete is a chemical reaction and temperature affects it. Hot, dry, windy conditions cause plastic shrinkage cracking; frost weakens a surface that freezes before curing. Both are manageable with the right mix, timing and protection — but they need to be actively managed rather than ignored.
When you can use it
Foot traffic after 24–48 hours, cars after seven days, and heavy vehicles after 28 days when the concrete reaches design strength. Driving on a slab too early causes damage that will not appear for months and is not covered by any guarantee.
Frequently Asked Questions
How thick should a concrete driveway be in NZ?
A residential driveway carrying cars is normally 100 mm thick over a properly compacted basecourse, with steel mesh reinforcement positioned within the slab depth and concrete typically in the 20–25 MPa range. If you will park a boat, campervan, trailer or work truck on it, or a delivery truck will use it, 125–150 mm is the right specification. The thickness should be written on your quote rather than assumed, because the difference between 100 mm and 150 mm is a real cost.
How long does a concrete driveway last?
A well-built concrete driveway gives 25–35 years and often longer. Concrete pavers can reach 30–50 years if joints are maintained, asphalt runs 15–20, and chip seal 10–15. What decides where you land is the quality of the base preparation rather than the concrete itself. Keeping control joints sealed, making sure water runs off rather than pooling, and sealing the surface will extend the life significantly for very little cost.
What does MPa mean on a concrete quote?
MPa — megapascals — is the compressive strength the concrete is designed to reach after 28 days of curing. Residential driveways in New Zealand are typically specified at 20–25 MPa. Higher strength mixes are used for commercial floors, hardstands and structural work. A higher MPa is not automatically better value on a driveway, because concrete strength does not compensate for an inadequate basecourse — the base is what determines whether the slab cracks.
Why does concrete crack, and can it be prevented?
Concrete shrinks as it cures, so some cracking is inevitable — the aim is to control where it happens rather than prevent it. Control joints create planned weak lines so the slab cracks along a straight line you barely notice. Uncontrolled cracking usually comes from an under-prepared base, a slab too thin for its load, reinforcement in the wrong position, joints spaced too far apart, or the surface drying too fast on a hot windy day. Anyone guaranteeing a driveway will never crack is overselling.
Does a concrete driveway need to be sealed?
It is not mandatory, but it is worthwhile, especially in colder parts of New Zealand. Concrete is porous, and water that soaks in expands when it freezes — repeated freeze-thaw cycling causes the surface to flake and pit over time. Sealing also gives you time to wipe up oil before it soaks in, and slows moss and lichen. A penetrating sealer lasts 5–10 years and is invisible; a topical acrylic lasts 1–3 years and enhances colour, which is why it is used on exposed aggregate and coloured concrete.
How soon can I drive on a new concrete driveway?
Foot traffic after 24–48 hours and cars after seven days as a minimum. Keep heavy vehicles, trailers, skip bins and delivery trucks off it for 28 days, which is when concrete reaches its design strength. Driving on it too early can cause cracking that does not become visible for months, and it will not be covered by a workmanship guarantee. Leave the barriers up even if the surface looks and feels hard.
Is it cheaper to resurface or replace a concrete driveway?
Resurfacing is roughly half the cost — around $70–$180 per square metre against $130–$260 to break out and re-pour — and it adds 8–15 years. But it only works where the existing slab is structurally sound with no active movement, because live cracking or settlement telegraphs straight through a new overlay. Cracks wider than about 6 mm, sections at different heights, or water now pooling where it used to drain all point to a base problem that resurfacing will not fix.
Get a Concrete Driveway Quote
Christchurch Concrete Driveways quotes with the specification written down — excavation, basecourse depth, slab thickness, concrete strength and reinforcement all itemised, so you know exactly what you are buying. Call 03 660 1155 for a free estimate.