Exposed aggregate concrete in Ferntree Gully

The finish that suits the foothills

Ferntree Gully gets more rain than suburbs further west, the streets are lined with big trees, and plenty of driveways are steep. Exposed aggregate handles all three. The stone surface grips when wet, the mix of colours hides the stains left by gum leaves and seed pods, and because tyres run on stone rather than cement paste, it wears slowly.

How it is made

The concrete is batched with a decorative stone blend. We place, level and float it so the stones sit just below the surface, then, when the concrete has firmed up enough, wash away the top layer of cement paste to reveal the stone. A surface retarder may be sprayed to control timing. Joints are saw-cut, the slab cures, and later the cement haze is cleaned off and the surface is sealed.

Timing is everything. Wash too early and stones loosen; too late and the paste will not come away cleanly. We plan pours around the forecast and staff the job so the wash happens at the right moment.

Choosing a stone blend

Blends range from light creams and whites through warm browns and honey tones to blue-grey basalt and charcoal mixes. Around Ferntree Gully: – grey and charcoal blends suit modern rebuilds, dark roofs and rendered homes – warm blends sit nicely beside cream or tan brick veneer – mixed blends with brown and grey hide red-brown clay and leaf stains best – a darker oxide in the cement makes stones stand out and hides tyre marks

We bring real samples to look at wet and dry, beside your house, in daylight.

Stone size

Fine stones give a smoother surface that is kinder to bare feet around pools and alfresco areas. Medium and coarse stones grip better on steep driveways. Many homes use the same blend throughout but choose a finer stone for paths and patios.

On steep driveways

On a steep Ferntree Gully drive, exposed aggregate's texture is a big advantage. We add saw cuts at sensible spacings along the slope, a smooth transition at the kerb and garage, and drains to catch runoff before it reaches the house.

The downsides worth knowing

– rougher underfoot than smooth concrete – coarse blends can trap leaves and hold moss on shaded blocks – the colour cannot be changed once poured – sealing every few years keeps the colour rich and resists stains A finer stone and a good sealer handle most of these.

Can exposed aggregate go over existing concrete?

True exposed aggregate needs a full-depth pour, because the stone is part of the mix. Over sound existing concrete, a thin decorative overlay can give a similar look, though it is not the same product and will not last as long. If your old slab is cracked or sunken, replacement is usually the better choice.

Exposed aggregate or pavers?

Pavers can be lifted and relaid, but on reactive clay the sand bed shifts and weeds grow in the joints. Exposed aggregate is one reinforced slab. The cost comparison depends on the paver, base and site, so we price both if you are weighing them up.

Borders, bands and combinations

A plain charcoal border frames exposed aggregate neatly against lawns and gardens and makes a tidy join at the council crossover if council requires a plain finish there. Bands across a long driveway break up the run and disguise joints.

Cleaning and sealing

A broom and hose handle everyday dirt. Moss in shaded corners responds to a suitable treatment and scrub. Re-seal every few years, or when water stops beading. We can clean and re-seal older exposed aggregate too.

Adding to existing exposed aggregate

Exact matches are rare because blends and weathering change. A border between old and new usually looks better than an attempted match.

Driving on new exposed aggregate

Cars usually after about a week, longer in cold weather, and heavier vehicles later still.

Your quote

After a free visit you get a written quote covering removal, excavation, base, steel, blend, finishing, joints, sealing and clean-up, each listed separately.

How exposed aggregate is made

Exposed aggregate starts as a normal pour, but with a mix that contains decorative stone. Once the concrete is placed and levelled, the surface is treated so the top layer of cement paste can be washed away at exactly the right time, revealing the stones underneath. Timing is everything: wash too early and stones pull out; too late and the paste will not budge. Weather in the foothills changes quickly, so we watch the slab closely through the afternoon and adjust our timing to the temperature, wind and humidity on the day.

After washing, the surface is cleaned again a few days later to remove residue, joints are cut, and sealing follows once the slab has dried enough.

Choosing a blend for a foothill home

Blends vary in colour, stone size and shape. Rounded river stones feel smoother underfoot; crushed stones give a sharper, grippier texture. Lighter blends with white quartz and grey basalt stay cooler in summer and brighten shaded areas, which suits many Ferntree Gully blocks under tall trees. Darker charcoal blends hide leaf stains and tyre marks well and suit modern homes with black or grey trims. Warmer browns and creams suit older brick homes and timber.

We bring sample boards to every visit so you can see them in your own light, against your bricks, cladding and roof colour. Looking at a sample in the shade and then in the sun often changes people's minds.

Borders and combinations

A border of plain or coloured concrete around exposed aggregate frames the driveway and gives a clean edge. Some homeowners mix two blends, or use exposed aggregate on the driveway and a honed version of the same mix on the alfresco, so the stones relate. Steps and paths can match the driveway or contrast with it.

Sealing exposed aggregate

Sealer protects the surface from stains, makes cleaning easier and can deepen the colour of the stones. In the foothills, where moss and leaf tannins are common, sealing makes a visible difference. Penetrating sealers keep a natural look; acrylic sealers give a richer, slightly glossy finish. On sloping driveways and steps we add an anti-slip additive.

Cleaning and moss

Shaded exposed aggregate can grow moss and algae in winter. A gentle pressure clean and a moss treatment once a year, followed by re-sealing every few years, keeps the stones bright and the surface grippy.

Fixing problems in older aggregate

Loose stones, dull colour and worn sealer are common in older exposed aggregate. Sound slabs can be cleaned, repaired and re-sealed. Badly cracked or sunken slabs are better replaced.

Exposed aggregate on steep sites

On steep driveways, the stones do much of the work of keeping tyres from slipping. A crushed stone of medium size gives the best grip. We avoid very fine finishes on steep grades and make sure the slab is thick enough at transitions, where braking forces are greatest. Drains across the slope stop water from sheeting down the surface and carrying grit into the garage.

Matching an existing slab

If you are extending an existing exposed aggregate area, we try to source the same or a similar blend. An exact match is rarely possible after weathering, so a border or joint between old and new usually looks better than a forced join.

Build specification at a glance

Foothill ground, rain and councils

Ferntree Gully sits where the Knox plains run up into the Dandenong Ranges. Below the lawns on the lower streets you usually find heavy grey and orange clay that holds water through winter and splits open in a hot February. Higher up toward Upper Ferntree Gully, Upwey and The Basin, the soil is a stony, brown hillside clay over weathered rock, and the slopes send a surprising amount of water downhill every time it rains. Old cut-and-fill from earlier house builds adds another variable. We dig a test hole on every property, take the soft material out, rebuild with compacted crushed rock chosen for what we found, and shape the surface so water always has somewhere to go.

Inside your own boundary, most driveways, paths and patios need no permit. The crossover, kerb and council footpath always do, and that consent comes from Knox City Council for most of our area or the Shire of Yarra Ranges for Upwey and parts of Upper Ferntree Gully, Lysterfield and The Basin fringe. House slabs, large garages and many retaining walls go through a building surveyor with engineering. Bushfire and vegetation overlays affect parts of the hills. Your quote names whatever applies.

What our Ferntree Gully quotes spell out

You will not get a single number scribbled on a business card. Our written quote breaks the job into the pieces that actually drive the outcome: the area in square metres, breaking out and disposing of whatever is there now, how far down we dig, the class and depth of crushed rock, slab thickness and the steel inside it, the finish or stone blend you chose, the joint plan, each drain, pit and length of pipe, step and edge work, sealing, and any Knox or Yarra Ranges paperwork. If the site needs a line pump, a long barrow run or protection for a neighbour's driveway, that is listed too.

We keep square-metre rates off this website on purpose. In the foothills, the work hidden below the finished surface varies hugely between two blocks in the same street: one might be firm and flat, the next steep, wet and full of old fill. Pricing sight unseen means guessing, and a guess ends up either padded or short. After a visit we can price the real job.