Grouting the joints on a brick patio is one of the most satisfying finishing steps — and with the right preparation and materials, it's well within reach for a capable DIYer. Whether you've laid clay bricks, concrete pavers, or recycled bricks, the process is largely the same: fill the gaps between bricks with a mortar or jointing compound, finish the surface neatly, and allow it to cure properly.
What You'll Need
Before you start, gather your materials and tools:
- Bagged mortar mix or dry jointing sand (see options below)
- Bucket and mixing paddle (or a stiff-bristle brush for dry methods)
- Pointing trowel or jointing iron
- Stiff brush or broom
- Garden hose with a gentle spray setting
- Sponge and clean water
- Safety gloves and eye protection
Choosing the Right Jointing Method
There are two main approaches for brick patio joints in NZ:
1. Wet Mortar Pointing
This is the traditional method and gives the most durable, professional result. You mix a sand-and-cement mortar (typically 4 parts coarse sand to 1 part Portland cement) to a stiff, workable consistency — similar to peanut butter. This suits clay bricks and situations where you want a rigid, long-lasting joint.
2. Dry Jointing Sand or Polymeric Sand
For concrete pavers or where you want a more flexible joint, polymeric jointing sand is a popular modern option. It's swept into the joints dry, then activated with water, which binds the particles together. It resists weeds and ants and is easier to apply than wet mortar. Products are available at Bunnings and Mitre 10.
| Method | Best For | Durability | DIY Difficulty |
|---|---|---|---|
| Wet mortar pointing | Clay bricks, feature patios | Very high | Moderate |
| Polymeric jointing sand | Concrete pavers, large areas | High | Easy |
| Plain kiln-dried sand | Temporary or low-traffic areas | Low | Very easy |
Step-by-Step: Wet Mortar Pointing
Step 1 – Prepare the joints. Make sure the gaps between bricks are clean and free of loose debris, weeds, or old mortar. Use a stiff brush or a cold chisel to clear out any loose material. Lightly dampen the bricks with a hose — this stops the dry brick from drawing moisture out of the mortar too quickly, which can cause cracking.
Step 2 – Mix your mortar. Combine 4 parts coarse sand with 1 part cement and add water gradually until you reach a stiff, workable consistency. Avoid making it too wet — sloppy mortar is harder to control and weaker when cured. You can add a small amount of plasticiser to improve workability.
Step 3 – Apply the mortar. Use a pointing trowel to press mortar firmly into the joints, working in small sections (about 1 square metre at a time). Pack the mortar in well to avoid air pockets, which can lead to cracking later.
Step 4 – Finish the joints. Once the mortar has started to stiffen (usually 20–40 minutes depending on temperature and humidity), use a jointing iron or the edge of your trowel to shape the joints. Common finishes include:
- Flush – level with the brick surface (easiest)
- Raked – slightly recessed for a shadow-line effect
- Rounded/bucket handle – a concave profile that sheds water well
Step 5 – Clean up. Before the mortar fully sets, use a damp sponge to wipe mortar smears off the brick faces. Avoid scrubbing too hard or you'll pull mortar out of the joints. Once fully cured (after 24–48 hours), any remaining haze can be removed with a diluted brick acid cleaner — follow the manufacturer's instructions carefully and rinse thoroughly.
Step 6 – Cure slowly. In hot or windy conditions, lightly mist the finished area with water over the first day or two to slow the curing process and reduce the risk of shrinkage cracks. Avoid foot traffic for at least 24 hours, and heavy use for 3–5 days.
Step-by-Step: Polymeric Sand
- Ensure joints are clean and dry.
- Pour the sand over the patio and sweep it into the joints with a stiff broom, working in multiple directions.
- Compact the sand by running a plate compactor over the area (hire one from a local hire shop), or tamp firmly by hand.
- Sweep off all excess sand from the brick surfaces — this is important, as any residue left on top will haze when wet.
- Gently mist the entire area with water to activate the binder. Follow the product's specific instructions for water quantity and timing.
- Allow to cure as directed (usually 24 hours) before use.
Tips for a Great Finish
- Work in the shade or on a cool day. Hot NZ summer sun dries mortar too fast, causing cracking. Early morning is ideal.
- Consistent joint width looks far better than uneven gaps — if your bricks are already laid, you're committed, but aim for uniformity in your pointing depth.
- Don't rush the clean-up. Mortar smeared and left to harden on brick faces is difficult to remove without damaging the surface.
- Check BRANZ for guidance on mortar mixes and paving best practice relevant to NZ conditions.
When to Call a Professional
Grouting a patio is generally DIY-friendly and doesn't require a building consent or licensed tradesperson. However, consider calling a qualified bricklayer or paving specialist (you can find one on tradedirectory.co.nz) if:
- Your patio is large and you're unsure about mortar consistency or joint finishing
- The existing brickwork has significant movement, cracking, or drainage issues that need diagnosing
- You're working with heritage or recycled bricks that require specific mortar mixes (hard mortars can damage soft old bricks)
- You want a guaranteed, professional finish for a high-visibility area
For any structural paving work connected to a building (such as a patio abutting a foundation), check with your local council whether a building consent is required under the NZ Building Code.
Licensed Building Practitioner (LBP)
