Exposed aggregate is ordinary structural concrete with a different last hour. Instead of being trowelled or broomed, the surface is washed back while it is still green to reveal the stone in the mix. The result is a driveway or patio that carries colour and texture all the way through, wears without showing it, and hides the tyre marks, leaf tannin and barbecue spills that make a plain slab look tired.
Choosing the stone
The look comes from three choices: the stone blend, the stone size and the colour of the cement around it. Suppliers keep sample boards, and the sensible way to choose is to see samples on site, in daylight, against the bricks and the roof. Dark blends suit the charcoal and render frontages of newer estates. Warmer river gravel blends sit better with the red brick and weatherboard of older Newcastle streets. Smaller stone is kinder under bare feet on a patio.
One frontage, one finish
The finish works best when it runs from the driveway to the porch and the front path in a single pour or a matched sequence of pours, because separate loads can vary slightly in colour. Plan the whole frontage at the measure even if part of it is poured later.
Where council draws the line
The crossing between your boundary and the kerb is council’s. Lake Macquarie accepts exposed aggregate there only where the stone is at least 75 percent rhyolite or basalt. Newcastle specifies plain broom finish, treats exposed aggregate as something that may be considered, and does not permit sealer on the crossing at all. The Section 138 guide has the detail. A clean saw cut at the boundary, decorative behind it and plain in front, is the common result.
Timing and weather
Washing back is time critical. Too early and stone is lost, too late and it will not expose. Hot westerlies and sudden coastal showers both shorten the window, so exposed pours are booked with an eye on the forecast and sometimes moved. That is normal, not a delay.
Exposed aggregate runs $130 to $185 per m². See the cost guide and the specification, price yours in the calculator, then request a measure.
Published rates are a guide for budgeting. The price for your job is the one on the written quote after a site measure.