For a standard garden path, the most widely recommended mix ratio is 1 part cement : 2 parts sand : 3 parts coarse aggregate (stone chips) by volume — often written as a 1:2:3 mix. This produces concrete in the range of 20 MPa, which is strong enough for foot traffic and light garden use. If you prefer to keep things simple, ordering 20 MPa ready-mixed concrete from a local supplier is a reliable alternative that takes the guesswork out of batching.
Understanding Concrete Mix Ratios
A mix ratio describes the proportions of the three main ingredients:
- Cement — the binder that holds everything together
- Sand (fine aggregate) — fills gaps and adds workability
- Coarse aggregate (crushed stone or gravel) — provides bulk strength
Water is the fourth ingredient. A good rule of thumb is to keep the water-to-cement ratio as low as possible while still achieving a workable mix — too much water weakens the finished concrete significantly. Aim for a mix that holds its shape when squeezed in your hand but isn't crumbly or sloppy.
Recommended Mix for a Garden Path
| Use | Mix Ratio (C:S:A) | Approx. Strength |
|---|---|---|
| Garden path (foot traffic) | 1:2:3 | ~20 MPa |
| Driveway or vehicle traffic | 1:1.5:3 | ~25–30 MPa |
| Structural footings | Consult engineer | 25–30+ MPa |
For a typical garden path that will only see foot traffic, the 1:2:3 ratio is well-proven and widely used across New Zealand. If your path will occasionally carry a wheelbarrow, ride-on mower, or similar light loads, you can strengthen the mix slightly by reducing the sand proportion to 1.5 parts.
Bagged Mix vs. Site-Batched vs. Ready-Mix
Pre-mixed bags
Products like general-purpose concrete mix bags (available from Bunnings or Mitre 10) are convenient for small paths. Just add water. Check the bag for the manufacturer's water-to-mix ratio — don't guess.
Site-batching
Mixing your own from separate bags of cement, sand, and aggregate gives you control and can be more economical for medium-sized jobs. Use a consistent measuring container (a bucket works well) and keep your ratios accurate.
Ready-mixed concrete
For paths longer than about 10–15 metres, ordering 20 MPa ready-mix from a local concrete plant is often more practical and consistent. Discuss your project with the supplier — they'll confirm the right grade and can advise on slump (workability).
How Thick Should a Garden Path Be?
For foot traffic, a slab thickness of 75–100 mm is standard. If you're laying on soft or poorly drained ground, consider:
- Compacting the subbase well (at least 100 mm of compacted hardfill or AP20 metal)
- Adding control joints every 1.5–2 metres to manage cracking
- A slight crossfall (about 1:100 slope) to shed rainwater
Good subbase preparation is just as important as the mix ratio — even perfect concrete will crack if laid on unstable ground.
NZ Climate Considerations
New Zealand's varied climate affects how you place and cure concrete:
- Hot, dry, or windy days — concrete can dry too fast, causing surface cracking. Work in the cooler part of the day and cover with wet hessian or plastic sheeting after finishing.
- Cold weather (below 10°C) — cement hydration slows dramatically. Avoid pouring if frost is forecast and keep the slab covered and warm for at least three days.
- Wet regions (West Coast, Northland) — ensure excellent drainage under and around the path to prevent heave and erosion.
BRANZ provides useful guidance on building in NZ conditions that applies to concrete work.
Do You Need a Building Consent?
Most garden paths are exempt from building consent under Schedule 1 of the Building Act 2004, but this depends on factors like size, proximity to boundaries, and your local council's rules. Always check with your local council before starting — don't assume your project is exempt. MBIE Building Performance has clear information on consent exemptions.
When to Call a Professional
While mixing and laying a simple garden path is well within the reach of a capable DIYer, consider hiring a qualified concreter if:
- The path is large, complex, or on a steep slope
- You need exposed aggregate, stamped, or coloured finishes
- The ground is unstable, waterlogged, or near tree roots
- You're unsure about drainage or subbase requirements
A professional concreter will get the mix, finish, and drainage right first time, saving you costly repairs later. You can find qualified local concreters on tradedirectory.co.nz.
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