Weeds pushing up between patio pavers are one of the most frustrating garden maintenance jobs for NZ homeowners — but with the right approach, you can get on top of them and keep them away long-term. The key is tackling both the existing weeds and the conditions that let them take hold in the first place.
Why Weeds Grow Between Pavers
Weeds don't actually grow up from deep soil in most cases — they germinate from seeds that blow in and settle into the joints between pavers, where dust, organic matter, and moisture collect. NZ's mild, damp climate (especially in Auckland, Waikato, and coastal areas) makes this even more of an issue, as joints stay moist and weed seeds germinate quickly year-round.
The real culprit is usually empty or eroded jointing material. When sand or mortar washes out over time, it leaves a perfect seed bed. Fixing the joints is the most effective long-term solution.
Step 1 — Remove Existing Weeds Thoroughly
Before you re-joint or treat anything, clear out what's already there:
- Hand-pull or use a weeding tool — a long-handled crack weeder or paving knife works well for getting roots out cleanly.
- Boiling water — pour it directly into joints to kill weeds naturally. It's safe around pets and kids once cooled, and won't harm your pavers. You may need a few applications.
- White vinegar (undiluted) — a popular natural option. Spray directly onto weeds on a dry, sunny day. It kills the top growth but may not always get the root, so repeat as needed. Avoid getting it on lawn edges or garden plants.
- Commercial weed killers — products containing glyphosate or acetic acid are available at Bunnings and Mitre 10. Always follow label directions carefully and keep away from stormwater drains, as runoff can harm waterways — this matters under NZ's Resource Management Act.
- Flame weeding — a gas torch briefly applied to weeds is effective, but use caution near dry timber, fences, or on hot days. Check WorkSafe NZ guidelines if you're unsure about safe use.
Step 2 — Re-Joint Your Pavers Properly
This is the single most effective long-term fix. Once weeds are cleared, re-filling the joints removes the habitat they need.
Polymeric Sand (Recommended)
Polymeric sand is the gold standard for paver joints. It contains fine sand mixed with binding agents that harden when activated with water, locking the joint and resisting weed germination, ants, and washout. It's widely available at Bunnings and Mitre 10 in various colours to suit your pavers.
How to apply:
- Make sure joints are clean, dry, and free of debris.
- Pour polymeric sand over the pavers and sweep it into the joints with a stiff broom.
- Compact lightly with a plate compactor or tamp by hand.
- Sweep off all excess sand from the paver surface — this is important, as any residue left on top will haze when wet.
- Mist with water gently to activate the binder. Follow the manufacturer's instructions for your specific product.
- Allow to cure fully (usually 24–48 hours) before use.
Mortar or Pointing Compound
For older-style mortared paving or natural stone, a sand-and-cement pointing mix or a ready-mixed jointing compound can be used. This is more rigid and suits formal paving styles. Products from Ardex or Sika include flexible jointing mortars suited to NZ conditions.
Regular Kiln-Dried Sand
Standard jointing sand is a budget option but washes out more easily and doesn't bind — weeds will return faster. It's better than nothing but not a long-term fix.
Step 3 — Ongoing Prevention
Even with good jointing, a little maintenance goes a long way:
- Sweep regularly to remove organic debris and seeds before they germinate.
- Re-apply a paver sealer every few years. Sealing the surface and joints makes them less hospitable to weeds and easier to clean. Check with your paver supplier for a compatible product.
- Check drainage — if water pools on your patio, it accelerates joint erosion. Make sure your patio has adequate fall (typically 1:100 minimum away from the house) as recommended under the NZ Building Code.
- Spot-treat early — pull or treat any new seedlings as soon as you see them, before they establish roots.
A Quick Comparison of Methods
| Method | Effectiveness | Longevity | Cost (approx.) |
|---|---|---|---|
| Hand weeding only | Moderate | Short-term | Low |
| Boiling water / vinegar | Moderate | Short-term | Very low |
| Re-jointing with polymeric sand | High | 5–10+ years | Moderate |
| Re-jointing with mortar | High | Long-term | Moderate–high |
| Paver sealer (after re-jointing) | Good (combined) | 2–5 years | Moderate |
When to Call a Professional
If your paving has significant structural issues — sunken pavers, poor drainage causing persistent damp, or large areas of failed jointing — it's worth getting a qualified landscaper to assess the job. Lifting and re-laying pavers to correct falls or fix a failed base is skilled work, and doing it properly the first time saves money in the long run. You can find experienced local landscapers on tradedirectory.co.nz to get quotes and advice for your specific situation.
Note that landscaping work is generally not restricted work under the Building Act, but if your patio is attached to the house or involves drainage connections, check with your local council whether a building consent is required. MBIE Building Performance has guidance on Schedule 1 exemptions.
Licensed Building Practitioner (LBP)
