Can I Use a Hired Concrete Mixer for a Driveway Job?

Yes, you can absolutely hire a concrete mixer for a driveway job — and for smaller driveways or sections, it can be a cost-effective DIY option. That said, concrete work is physically demanding, time-sensitive, and unforgiving of mistakes, so it pays to understand what you're taking on before you start.

Is a Hired Mixer Right for Your Driveway?

A hired drum mixer (typically 60–120 litre capacity) suits small to medium driveway sections — think a single-car pad, a short path to a garage, or a section of driveway you're replacing in stages. For a full double-car driveway or anything over roughly 10–15 square metres, you'll likely find a hired mixer slow and exhausting. In those cases, ordering ready-mix (transit mix) concrete delivered by truck is usually more practical and gives you a more consistent result.

As a rough guide:

• Under ~5 m² — a hired mixer is very manageable
• 5–15 m² — possible with a helper, but plan your day carefully
• Over 15 m² — seriously consider ready-mix or hiring a professional concreter

Getting the Mix Right

For a residential driveway, you need a strong, durable mix. A standard driveway slab should be at least 100 mm thick (125 mm is better for vehicle loads), and the concrete should have a compressive strength of at least 25 MPa — often written as a 1:2:3 mix (one part cement, two parts sand, three parts aggregate) with a water-to-cement ratio kept as low as workable (too much water weakens the slab).

Key tips for mixing:

• Use clean, sharp sand and 20 mm crushed aggregate (available from most landscape suppliers or Bunnings and Mitre 10)
• Measure by volume consistently — a shovel or bucket count works well
• Add water gradually; the mix should hold its shape when squeezed but not be sloppy
• Mix each batch for at least 3–4 minutes before pouring

Preparation Is Everything

No matter how good your mix is, a poorly prepared base will cause cracking and subsidence. Before you pour:

1. Excavate to the correct depth — typically 100–150 mm for the slab plus 75–100 mm of compacted base course (AP20 or similar)
2. Compact the sub-base thoroughly with a plate compactor (also hireable)
3. Set your formwork (timber edging) to the correct level and slope — driveways need a minimum 1:100 fall away from buildings to drain properly, in line with NZ Building Code clause E1 (Surface Water)
4. Lay reinforcing mesh (typically reinforcing mesh (check the appropriate mesh specification with your supplier or engineer for your specific slab design)) on bar chairs so it sits in the middle third of the slab
5. Dampen the base before pouring to prevent the sub-base from drawing moisture out of the fresh concrete

Do You Need a Building Consent?

In many cases, a residential driveway slab does not require a building consent under Schedule 1 of the Building Act 2004 — but this depends on your specific situation, including proximity to boundaries, retaining walls, or stormwater systems. Always check with your local council before starting, as rules vary by region and property. You can find general guidance at MBIE Building Performance.

Pouring, Finishing, and Curing

Once you start pouring, you need to work efficiently — concrete begins to set within 1–2 hours depending on temperature and humidity.

• Pour in sections and screed (strike off) each section level with your formwork using a straight-edged timber or screed board
• Use a bull float to smooth the surface and push aggregate down
• Add control joints (saw cuts or tooled grooves) every 3–4 metres to control where cracking occurs
• Finish the surface with a broom finish for grip — important for a driveway
• Cure the slab by keeping it moist for at least 7 days (cover with wet hessian or use a curing compound) — this is critical in NZ's variable climate, especially in hot, dry, or windy conditions

BRANZ has useful technical guidance on concrete slab construction and curing best practice.

Hiring the Equipment

Most hire centres across NZ — including those listed on Mitre 10 and PlaceMakers — offer electric or petrol drum mixers, plate compactors, screeds, and finishing tools. Book ahead, especially in summer when demand is high. As a rough guide, expect to pay somewhere in the range of $60–$120 per day for a mixer, though rates vary by region and supplier — always confirm current pricing directly with your hire centre.

When to Call a Professional

While a hired mixer is a legitimate DIY tool, there are situations where you should engage a qualified concreter:

• The driveway is large, steeply sloped, or has complex drainage requirements
• You need a coloured, exposed aggregate, or stamped finish
• The ground conditions are poor (clay, fill, or unstable soil)
• You're unsure about consent requirements or structural loads (e.g., heavy vehicles)
• You've never worked with concrete before and the job is time-critical

A professional concreter will also have access to ready-mix trucks, vibrating screeds, and power floats that produce a far superior result on larger jobs. You can find qualified local concreters on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – Building consents and Schedule 1 exemptions
• BRANZ – Concrete construction guidance
• Bunnings – Concrete and mixing supplies
• Mitre 10 – Tool hire and concrete products
• PlaceMakers – Concrete and construction materials
• WorkSafe NZ – Manual handling and site safety