Exposed aggregate driveways in Ballarat.

A standard concrete driveway is a single homogeneous slab finished smooth (steel trowel) or textured (broom). An exposed-aggregate driveway uses a slightly different mix — the same 32MPa structural concrete underneath, but with a top 25–30mm of concrete designed to be partially washed off after pour, exposing the decorative stone.

The job sequence: pour the slab, screed level, finish off with a wood float, then spray on a surface retarder that delays the set of just the top few mm. Six to twelve hours later (depends on temperature), high-pressure wash off the retarded paste, revealing the stones. Acid-etch and seal at day 8.

Aggregate options for Ballarat.

• Castlemaine slate (grey-blue): the regional classic. Ages well, grey-tones complement Colorbond Surfmist or Monument facades. ~$115/m².
• Tasmanian black basalt: almost-black, dramatic. Pairs with white Colorbond. Hides oil drips. ~$130/m².
• Bendigo creek pebble: warm honey and tan tones. Suits brick veneer and heritage homes. ~$120/m².
• White quartz / Cowra granite mix: very pale, modern. Care needed in north Ballarat where ag-residue can stain. ~$140/m².
• Custom blended mix: two or three stones in proportion. Adds $10–$15/m².

Why exposed aggregate suits Ballarat.

Hides hairline cracks. The textured surface visually breaks up any thermal hairlines that develop in the first 24 months. They’re still there structurally but invisible at standing distance.

Slip-resistant. Plain trowel-finished concrete is dangerous when wet or frosted. Exposed aggregate has a permanent texture that gives grip year-round — matters in Ballarat from May through September when overnight frosts are routine.

Estate-covenant-compliant. Stockland Lucas, Greenhill, and most Ballarat new-build estates require a decorative finish to the front driveway. Exposed aggregate is on the approved list everywhere we work.

Common pitfalls (and how we avoid them).

• Patchy stone exposure — caused by uneven retarder application. We use a calibrated low-pressure sprayer, not a hand pump.
• “Mud cracking” on the surface — caused by washing off too late (retarder over-cures). We monitor temperature and time the wash to the hour.
• Oxide staining around aggregate — from cheap basalt with high iron content. We source from Boral, BCSands or Mawsons only.
• Sealer flaking after 18 months — from solvent-based sealer in cold-cycle climates. We use a water-based polyurethane that flexes with freeze-thaw.

Pricing.

Standard exposed aggregate, single-stone mix, ~50–80m² residential driveway in Ballarat: $110–$150/m² fully installed. That includes excavation, 100mm Class 3 base, SL92 mesh, 32MPa concrete with freeze-resistant additive, retarder, wash-off, acid etch, sealer, and 7-day cure under hessian. Crossover and council permit additional — usually $1,200–$1,800 for crossover concrete + $260 permit + $1,500 refundable bond.