Exposed aggregate driveways in Newcastle and Lake Macquarie

Exposed aggregate is ordinary concrete with a decision made at the top few millimetres. The slab is poured with a chosen stone in the mix, a retarder is applied to the surface, and the next day the cement paste is washed off to leave the stone standing proud. What you see is the aggregate, not the cement, which is why it hides tyre marks, oil drips and leaf stains that show on a grey slab, and why it has become the default finish on new estate frontages from Fletcher to Cameron Park.

The cost of an exposed aggregate driveway

$130 to $185 per square metre supplied and laid. A 36 m² single driveway comes out at $4,680 to $6,660 and a 60 m² double at $7,800 to $11,100. The spread inside the range is mostly the stone: a local river gravel sits at the bottom, a specialty stone trucked in from elsewhere sits at the top. Sealing is normally included in the rate; ask the quote to say so. Where an old driveway comes out first, allow about $35 per square metre on top. Worked examples and a calculator are on the cost pages.

Choosing the stone

The three questions are colour, size and where the driveway ends. Colour is what you see from the street, and most owners hold a sample against the roof, the render or the brick before deciding. Size runs from a fine 7 mm pea gravel, which reads as a texture, to 14 mm and 20 mm stone, which reads as individual pebbles. Where the driveway ends matters because of the crossing. Lake Macquarie City Council accepts exposed aggregate on the crossing only when rhyolite or basalt makes up 75 percent or more of the stone, so a driveway that is meant to run unbroken to the gutter in Lake Macquarie starts from a shortlist of dark stones. City of Newcastle’s drawing lists exposed aggregate among the finishes it “may consider” on the crossing, and its default is plain broom finish.

Sealing, and the one place you cannot

A penetrating or film sealer after the wash locks the stone in, deepens the colour and stops oil soaking in. It is reapplied every few seasons depending on the product and the sun the driveway gets. On a crossing in the City of Newcastle sealer is not permitted at all, so the seal stops at the boundary line. In Lake Macquarie a sealed crossing is acceptable where the stone meets the 75 percent rule.

Grip on a slope

Because the stone stands above the cement, an exposed surface grips well in the wet, better than a smooth coloured slab and close to a broom finish. On the steep driveways of Charlestown, Kotara and Toronto it is a sound choice, provided the wash is not so deep that stones loosen with traffic. The specification holds the depth of exposure to a fraction of the stone size for that reason.

Same slab underneath

Exposed aggregate changes the surface, not the structure. Under it the specification is the same as for a plain driveway: compacted base, 100 mm of 25 MPa concrete inside the boundary, SL72 mesh on chairs, joints at no more than 3 metres, and the crossing to the council’s own thickness. The difference in price buys the stone, the extra labour at the wash and the seal, not a thicker slab.

Before the pour

A new, widened or replaced crossing needs approval from the council first, and with exposed aggregate the finish is part of what council decides. The Section 138 guide explains where each council draws its line. When an existing driveway is coming out, see removal and replacement; when the front path or the alfresco is to match, see paths, slabs and patios.

Request a measure and a written quote for the whole frontage at once.