Exposed aggregate in Korumburra

Why exposed aggregate suits this town

Korumburra gets a lot of rain, a fair share of frost and plenty of red-brown clay tracked in from paddocks, building sites and unsealed roads. On a steep street that combination is hard on a smooth concrete surface. Exposed aggregate deals with it well. The washed surface leaves the tops of the stones standing slightly proud, which gives tyres and shoes a mechanical grip even when the slab is wet. The mixed colours of the stone also hide mud, leaf stain and tyre marks far better than a flat grey finish.

It is also a finish that looks at home here. Exposed aggregate sits comfortably beside weatherboard cottages in the older streets near the town centre, brick veneer homes from the seventies and eighties, and the newer houses going up on the edges of town. Because the colour comes from real stone rather than a surface coating, it ages gently instead of wearing through in patches.

How the finish is made

Exposed aggregate is not a coating. It is a concrete mix that contains a decorative stone blend, placed and finished in the normal way. A surface retarder is then applied so that the top few millimetres of cement paste stay soft while the rest of the slab sets. At the right moment, usually the following morning, that soft layer is washed away with water and brushing to reveal the stones. Too early and stones can be loosened. Too late and the paste is too hard to remove evenly. Getting that timing right in Korumburra weather, which can swing from warm to cold and wet in a day, is a big part of the craft.

After the wash, the surface is cleaned again to remove any cement haze, joints are cut, and the slab is left to cure. Sealing, if it is part of the job, comes later once the concrete has dried enough.

Choosing the stone

Suppliers offer a range of stone blends, from creamy and honey tones through to blue-grey and charcoal mixes, and in different stone sizes. Smaller stone gives a finer, more even texture that is comfortable underfoot. Larger stone gives a bolder look and a little more grip. We bring physical samples to the site visit so you can see them in daylight against your brickwork, weatherboards, roof colour and garden. A sample that looks warm in a showroom can look quite different on a grey South Gippsland afternoon.

We also talk about the paste colour. Plain grey cement paste between the stones gives one look; a tinted paste can warm up or darken the overall surface. It is a small decision that changes the result noticeably.

Base preparation still decides the result

A beautiful finish on a poor base will still crack. Korumburra clay moves with the seasons, and slopes add their own stresses. We excavate to firm ground, remove topsoil and soft spots, compact crushed rock in layers, and set steel on chairs. On sloping sites we shape the subgrade so the slab has an even thickness rather than becoming thin at the edges. Saw-cut joints are planned to suit the shape of the area so shrinkage cracks fall in straight lines, and the joint pattern is laid out so it looks deliberate rather than random.

Combining finishes

Exposed aggregate works well with other finishes. A common choice is exposed aggregate across the main driveway with a smooth or broomed border band, or exposed aggregate at the front of the house with plain broomed concrete further back where the drive runs past the shed. Paths and patios can be done in the same stone so the whole property ties together. On very steep sections we sometimes recommend a coarser blend for extra grip, and on patios we might suggest a finer blend that is comfortable for bare feet.

Driveways, paths, patios and pool surrounds

Most exposed aggregate we pour in Korumburra is on driveways, but it is equally useful for front paths, side paths that stay damp in shade, patios that catch leaf litter, and pool surrounds where grip matters. For outdoor living areas, we discuss sealing so spills and barbecue fat are easier to clean.

Sealing and long-term care

Sealing is optional but worthwhile on many exposed aggregate jobs. A good sealer deepens the stone colour, reduces staining and makes cleaning easier. On a slope or around a pool, the sealer must keep grip, so we use products suited to outdoor trafficked areas and can add an anti-slip additive. Sealers wear over time and need reapplying every few years depending on traffic and sun. Day to day, a hose and a stiff broom are enough. Avoid leaving soil or fertiliser piles on the surface for long, and clean up oil spills promptly.

Repairs and replacement

Exposed aggregate is hard to patch invisibly because each pour has its own stone distribution and colour. If a section has failed, we will often recommend replacing whole panels between joints rather than small patches. That keeps repairs neat and the joint lines straight. If your old exposed aggregate has simply gone dull, a clean and reseal can bring much of the colour back without new concrete.

Exposed aggregate on steep Korumburra driveways

On a steep drive, exposed aggregate is placed and washed in manageable sections so the mix does not slump downhill before it sets and the wash can be timed evenly across the whole surface. Construction joints between sections are planned to line up with saw cuts, so the finished drive reads as one tidy surface rather than a patchwork.

Typical exposed aggregate specification

Korumburra clay, slopes and South Gippsland rules

Korumburra sits high in the hills of South Gippsland, at the edge of the Strzelecki foothills, in country that was cleared for dairying and once mined for black coal. Under the grass most blocks have heavy, reactive clay over weathered sandstone and mudstone. That clay swells in a wet winter and shrinks in a dry summer, and on a slope it also wants to creep downhill. A slab poured thin, straight onto it, will crack and move.

So we dig to firm ground, take out topsoil and soft material, compact crushed rock in layers, set steel on chairs, and plan joints and drainage before the pour. Falls are designed to take water safely down the hill, away from the house and garage, to a legal point of discharge. High rainfall makes compaction harder in winter, and frost and cold slow curing, so we plan around the season. Concrete inside your boundary rarely needs a council permit. Work in the road reserve, such as a crossover, nature strip or public footpath, generally needs the council's consent. A slab that carries a building needs a building permit and engineering. Your quote spells out which of these apply.

How a Korumburra quote is put together

Every quote we send is written and itemised. It sets out the area we measured, the digging and where the spoil or old concrete will go, the compacted crushed-rock base, the slab thickness, the steel and how it is supported, the finish, any sealer, and the extras that hilly blocks often need: drains, steps, a small wall, a landing or a new crossover. If South Gippsland Shire, the state road authority or a building surveyor has to be involved, the quote names that up front.

It also covers the practical side of pour day: where the truck or pump can stand on a steep street, how we protect gardens, fences and the footpath, and how long the area must stay closed. If we suspect the ground hides a problem, such as wet clay, an old slab, a spring or a buried pipe, we say so and explain how we would deal with it. There are no prices on this website because two blocks on the same Korumburra street can need very different work. The visit and the written quote cost you nothing.