Can I Lay Concrete Pavers Directly onto Compacted Sand in NZ?

Yes, you can lay concrete pavers directly onto a compacted sand bedding layer in New Zealand — but the sand alone isn't enough. The real secret to a long-lasting paved surface is what goes underneath the sand. Get the sub-base wrong and you'll be dealing with sunken, cracked, or shifting pavers within a season or two, especially given NZ's variable climate and soil conditions.

How the Layered System Works

A properly built paved surface is a sandwich of layers, each doing a specific job:

• Subgrade – the natural ground, shaped and compacted
• Sub-base – a layer of compacted aggregate (AP40 or AP65 crushed rock is commonly used in NZ)
• Bedding sand – a 25–40 mm layer of coarse, angular bedding sand (not beach or fine sand)
• Pavers – your concrete pavers, laid and compacted into the sand
• Jointing sand – swept into the joints to lock everything together

The compacted sand layer is the bedding layer, not a structural base on its own. It allows you to fine-tune the level of each paver and provides a stable, even surface for them to sit on.

Sub-Base Depth: Getting It Right for NZ Conditions

The required sub-base depth depends on the intended use of the surface:

NZ soils vary enormously — from stable gravels in Canterbury to expansive clays in Auckland and Waikato. Clay soils in particular can heave and shrink with moisture changes, so you may need a deeper sub-base or geotextile fabric between the subgrade and aggregate. If you're unsure about your soil type, a local driveway layer or civil contractor can assess it for you.

Choosing the Right Sand

Not all sand is suitable for paver bedding. You need coarse, angular, washed bedding sand — sometimes called concrete sand or coarse river sand at NZ suppliers. Avoid:

• Fine beach sand (it compacts poorly and shifts)
• Builders' sand (too fine)
• Any sand with a high clay or silt content

The bedding sand layer should be laid at 25–40 mm uncompacted, which will compact down to roughly 20–30 mm once the pavers are vibrated in. Do not wet the sand before laying pavers — this causes uneven settlement.

Step-by-Step: Laying Pavers on Sand

1. Excavate to the required depth (sub-base + 30 mm sand + paver thickness, plus 10–20 mm for finished level above surrounding surfaces for drainage).
2. Compact the subgrade with a plate compactor.
3. Lay and compact the sub-base aggregate in 100 mm lifts.
4. Screed the bedding sand to a consistent depth using timber rails or screed pipes as guides.
5. Lay pavers in your chosen pattern, keeping joints tight (typically 2–5 mm).
6. Compact the pavers with a plate compactor (use a rubber pad or foam sheet to protect the paver surface).
7. Sweep jointing sand into the joints and compact again. Repeat until joints are full.

Drainage and Falls

Under the NZ Building Code clause E1 (Surface Water), paved surfaces must be graded to direct water away from buildings and boundaries. A minimum fall of 1:100 (1 cm drop per metre) is generally recommended for paved areas, though steeper falls are better for driveways. Poor drainage is one of the most common causes of paver failure in NZ — water pooling under pavers softens the sand bed and leads to sinking. Check MBIE Building Performance for guidance on surface water management requirements.

Do You Need a Building Consent?

In most cases, laying a residential driveway or path with concrete pavers is exempt from building consent under Schedule 1 of the Building Act 2004. However, exemptions have conditions — for example, work must not affect drainage in a way that causes issues for neighbouring properties. Always confirm with your local council before starting, as rules can vary by district and site-specific factors (such as proximity to a boundary or retaining walls) may apply.

Common Mistakes to Avoid

• Skipping the sub-base and laying sand directly on subgrade — this is the number one cause of failure
• Using too much sand — a thick sand layer is not more stable, it's less stable
• Not compacting each layer properly before moving to the next
• Ignoring drainage — always plan your falls before you start excavating
• Laying pavers in wet conditions — sand and subgrade should be dry and firm

When to Call a Professional

While laying pavers is a popular DIY project, there are situations where it's worth bringing in a qualified driveway layer or landscaping contractor:

• Driveways for vehicles, especially if the ground is soft, sloped, or has poor drainage
• Large areas where getting consistent levels is critical
• Sites with clay or problem soils that need specialist sub-base treatment
• Areas near retaining walls or structures where drainage and loading need careful consideration

A professional will have access to proper compaction equipment and the experience to spot problems before they become expensive. You can find qualified local driveway layers and landscaping contractors on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – Building Code and consent information
• BRANZ – Build magazine and technical guidance for NZ construction
• WorkSafe NZ – Safe use of compaction equipment and site safety
• Bunnings NZ – Paver and landscaping supplies
• Mitre 10 NZ – Bedding sand, aggregate and paving products
• PlaceMakers – Aggregate and construction materials