How to Re-Level Pavers That Have Shifted or Sunk

Sunken or shifted pavers are one of the most common driveway and path problems NZ homeowners face, and in many cases it's a straightforward DIY repair. The key is understanding why the pavers moved before you simply lift and relay them — otherwise the problem will come back within a season or two.

Why Do Pavers Shift or Sink?

Before grabbing a spade, it pays to diagnose the cause:

• Poor or eroded bedding sand – the most common culprit. Sand washes out over time, especially in high-rainfall regions.
• Unstable sub-base – if the compacted aggregate base wasn't deep enough or well-compacted, it will settle under load.
• Tree roots – roots growing beneath pavers will lift and crack them.
• Poor drainage – water pooling under the surface softens the base. NZ's Building Code clause E1 (Surface Water) requires surface water to drain away from buildings; poor grading often contributes to paver movement.
• Edge restraint failure – if the border edging has moved, pavers lose lateral support and spread outward.
• Heavy vehicle loads – a driveway laid to foot-traffic standards won't cope with cars or trucks long-term.

Identifying the root cause means you can fix it properly, not just patch over it.

Tools and Materials You'll Need

• Flat pry bar or paver puller (hire from most tool hire shops)
• Rubber mallet
• Spirit level and string line
• Stiff brush and garden hose
• Coarse bedding sand (also called washed concrete sand or coarse river sand — not fine beach sand)
• Compactable aggregate (AP20 or AP40 crushed rock) if the sub-base needs topping up
• Plate compactor (hire recommended for anything more than a few pavers)
• Polymeric jointing sand or standard coarse sand for re-jointing

Step-by-Step: Re-Levelling Sunken Pavers

1. Mark and Lift the Affected Pavers

Use chalk or a marker to outline the area needing repair — always lift a slightly larger area than the visible problem, as adjacent pavers are often affected too. Insert a flat pry bar into the joint and lever the paver up gently. Stack pavers carefully on a flat surface so they don't chip.

2. Assess and Repair the Sub-Base

Once pavers are lifted, check the compacted base layer:

• If it looks solid and level, the issue is likely just the bedding sand layer.
• If it's soft, crumbly, or waterlogged, you'll need to excavate further, add fresh compactable aggregate (AP20), and compact it thoroughly with a plate compactor before re-sanding.
• A typical driveway sub-base should be 100–150 mm of compacted aggregate for vehicle traffic. Paths can be less, but check with your supplier.

3. Re-Screed the Bedding Sand

Spread a 25–30 mm layer of coarse bedding sand over the compacted base. Use two lengths of pipe or timber as screeding rails set to your desired finished level, then drag a straight-edged board across them to create a smooth, even surface. Do not compact or wet the sand at this stage — it needs to stay loose so the pavers can be tapped into it.

4. Re-Lay the Pavers

Place pavers back into position, maintaining consistent joint gaps (typically 2–5 mm). Use a string line and spirit level frequently to check alignment and level as you go. Tap each paver firmly into the sand bed with a rubber mallet. Avoid walking on freshly laid pavers until the whole section is complete.

5. Compact and Joint

Once all pavers are back in place, run a plate compactor over the area (place a rubber mat or piece of carpet under the plate to protect paver surfaces). This beds the pavers evenly into the sand.

Sweep jointing sand (or polymeric jointing sand for better weed and washout resistance) across the surface and work it into the joints with a stiff brush. Compact again, then top up joints as needed. Polymeric sand is activated with a light misting of water — follow the manufacturer's instructions carefully.

6. Check Drainage

Use a hose to check water flows away from the house and doesn't pool. A minimum fall of 1:100 (1 cm drop per metre) is a general guide for paved surfaces draining away from structures.

Fixing Pavers Lifted by Tree Roots

If roots are the cause, you have a harder decision to make. Cutting roots can damage or kill the tree, and may require an arborist's advice. In some cases, raising the entire paved area or installing a root barrier is the better long-term solution. This is worth discussing with a professional driveway layer.

When to Call a Professional

Call a qualified driveway layer or paving contractor if:

• A large area (more than a few square metres) has sunk — this usually signals a sub-base failure that needs proper excavation and re-compaction.
• The problem keeps recurring after DIY repairs.
• You suspect drainage issues that may affect your home's foundations (relevant to NZ Building Code clause E1).
• Tree roots are involved and you're unsure how to proceed.
• The driveway is used by heavy vehicles and needs a structurally engineered solution.

A good local driveway professional can assess whether a repair or full re-lay is the smarter investment. You can find qualified driveway layers in your area on tradedirectory.co.nz.

Note: Driveway and paving work is generally not restricted work under NZ law, so homeowners can tackle it themselves. However, if any drainage work connects to stormwater infrastructure, check with your local council, as some connections may require consent or a licensed drainlayer under the Plumbers, Gasfitters and Drainlayers Board rules.

Sources & Further Reading

• MBIE Building Performance – Building Code Clause E1 Surface Water
• BRANZ – Paving and Drainage Guidance
• Bunnings NZ – Paving and Landscaping Products
• Mitre 10 NZ – Paving Sand and Aggregates
• PlaceMakers – Aggregates and Landscaping Supplies
• WorkSafe NZ – Safe Use of Plate Compactors and Hire Equipment