Getting your paving base right is the single most important factor in whether your path or patio lasts for decades or starts rocking and sinking within a couple of years. In New Zealand, our variable soils — from Auckland's heavy clay to Canterbury's free-draining gravels — mean there's no one-size-fits-all answer, but the principles are consistent: good compaction, adequate depth, and proper drainage.
Why the Base Matters So Much
Pavers themselves are tough, but they rely entirely on what's underneath them. A poorly prepared base leads to settlement, heaving, cracking, and water pooling. Most paving failures that tradespeople are called in to fix aren't about the pavers at all — they're about a base that was too thin, not compacted, or didn't drain properly. BRANZ research consistently highlights drainage and compaction as the leading causes of paving deterioration in residential settings.
The Three-Layer System
A well-built paved surface uses three distinct layers:
1. Sub-base (Compacted Aggregate)
This is the structural foundation. In most NZ residential situations, you'll use AP40 or AP65 crushed aggregate (also called road base or compacted gravel). This is the same material used under driveways and roads.
- Paths and lightly trafficked areas: aim for at least 100 mm of compacted aggregate
- Driveways or areas with vehicle traffic: 150–200 mm is more appropriate
- On soft or clay soils (common in Auckland, Waikato, and parts of Wellington), you may need to go deeper or add a layer of geotextile fabric beneath the aggregate to prevent clay migration upward
Always compact the sub-base in layers using a plate compactor — don't try to compact it all at once. Hire a plate compactor from Bunnings or Mitre 10 if you don't own one.
2. Bedding Layer
On top of the compacted sub-base goes a bedding layer, typically 30–50 mm thick. This is what you set the pavers into and use to achieve a level surface.
| Paver Type | Recommended Bedding | Notes |
|---|---|---|
| Concrete pavers | Coarse bedding sand (AP7 or similar) | Most common, easy to work with |
| Natural stone (schist, bluestone) | Coarse sand or fine chip | Avoid fine beach sand — it shifts |
| Porcelain pavers | Dry mortar mix or full bed mortar | Porcelain needs a more stable bed |
| Brick pavers | Coarse bedding sand | Classic choice, forgiving to lay |
Coarse, washed bedding sand (sometimes called river sand or concreting sand) is the standard choice for most concrete and brick pavers. Avoid fine or silty sand — it compacts poorly and can wash out.
3. The Pavers Themselves
Once your base and bedding are right, laying the pavers is the straightforward part. Ensure consistent joint spacing (typically 3–5 mm for most pavers) and use a rubber mallet to bed each paver firmly and evenly.
Drainage: The NZ Factor
New Zealand's rainfall — particularly in the upper North Island and West Coast — means drainage is non-negotiable. Your paved surface should have a fall of at least 1:100 (1 cm drop per metre) away from buildings and toward a garden bed, drain, or lawn. This aligns with good practice under the NZ Building Code, particularly around keeping water away from foundations.
If you're paving a large area, consider permeable jointing sand or open-jointed pavers to allow some water to soak through rather than all running off. This is increasingly encouraged for environmental reasons and can reduce stormwater runoff into the street.
Soil Type and Ground Preparation
Before you place a single stone of aggregate, you need to excavate and prepare the ground:
- Remove all topsoil, grass, and organic material — organic matter breaks down and causes settlement
- If you hit soft, spongy, or waterlogged ground, dig deeper and consider a layer of geotextile fabric
- On clay soils, allow extra time — clay can be unstable when wet and hard when dry, so compact it thoroughly before adding aggregate
- On sandy or free-draining soils (common in parts of Canterbury and Hawke's Bay), you may need less aggregate depth but should still compact well
You can find aggregate, bedding sand, and geotextile fabric at PlaceMakers or your local landscape supply yard.
Edging and Restraints
Don't overlook edge restraints — without them, pavers gradually migrate outward and joints open up. Options include:
- Concrete haunching (a small concrete border poured around the perimeter) — the most permanent solution
- Plastic or aluminium edging — quick and effective for garden paths
- Timber edging — attractive but will eventually rot; use treated timber rated for ground contact
Common Mistakes to Avoid
- Skimping on depth — the most common DIY error
- Not compacting in layers — dumping 200 mm of aggregate and compacting once doesn't work
- Using the wrong sand — fine or beach sand shifts and washes out
- Ignoring drainage — flat paving leads to pooling and slippery surfaces
- Laying on wet clay — wait for dry conditions before compacting clay subgrades
When to Call a Professional
For small garden paths, a confident DIYer can absolutely tackle paving themselves. However, consider hiring a qualified landscaper for:
- Large driveways — vehicle loads require proper engineering of the base
- Sloped or terraced sites — retaining walls and drainage design may be needed
- Areas near the house foundation — incorrect drainage can cause moisture issues and may affect your building consent obligations under the NZ Building Code
- Retaining walls over 1.5 m — these require a building consent and may need engineering sign-off
A skilled local landscaper will have access to commercial compaction equipment and will know the soil conditions in your area. You can find qualified landscapers in your region at tradedirectory.co.nz.