Finish · Charlotte NC

Exposed Aggregate

Wash the paste back and let the stone do the work

In detail

What to know about exposed aggregate

How the finish is made

A surface retarder is sprayed onto the fresh slab, which holds back the cure of the top few millimetres of cement paste while everything below sets normally. The next day that softened skin is washed off with water and brushes, uncovering the stone in the mix. Nothing is glued on and nothing is applied — you are simply seeing the aggregate that was always there. That is why the finish is so durable: there is no layer to wear through, because the wearing surface is the stone itself.

The stone is the design decision

Everything about the look comes from the aggregate specified in the mix, so this decision is made at the plant before a truck leaves, not on site. River gravel gives rounded, warm, multi-coloured stone. Crushed granite reads cooler, sharper and more uniform. Specialist mixes with black basalt or quartz are available and cost more. The size matters as much as the type — a small pea gravel gives a fine, even texture that suits a walkway, while a larger stone gives a bolder surface better matched to a broad driveway.

Exposure depth changes everything

The same mix washed to three different depths gives three different surfaces. Light exposure just breaks the paste and hints at the stone, staying relatively smooth underfoot. Medium exposure, which is what most people picture, reveals the stone to about a third of its diameter. Deep exposure uncovers stone nearly to its full width and is dramatic but coarse, and it is genuinely uncomfortable to walk on barefoot. We agree the depth against how the surface will be used, and on pool decks we deliberately stay lighter than the showroom sample.

Grip, and where that matters

Exposed aggregate has the best natural slip resistance of any concrete finish we install, because the texture is mechanical rather than a coating that can wear away or be sealed over. That makes it a strong choice for pool surrounds, sloped driveways and shaded north-facing paths that stay damp. It is the one finish where the practical argument and the aesthetic argument point the same way, which is why it has stayed in use for decades while other decorative fashions have come and gone.

The honest drawbacks

The texture that provides the grip also catches dirt, and an exposed aggregate surface under trees needs washing more often than a smooth one. It is harder to clean spills from, so it is a poor choice directly under an outdoor kitchen. Repairs are close to impossible to hide, because matching stone, exposure depth and a decade of weathering all at once is not realistic — so we form and joint the work to keep any future repair confined to a whole panel rather than a patch in the middle of one.

Commonly used for

Patios Pool Decks Outdoor Living Areas Walkways & Entries Decorative Driveways Courtyards & Surrounds

Other finishes

Six alternatives

Stamped Concrete

Texture pressed into the slab while it is still green

Stained Concrete

Colour that reacts with the slab rather than sitting on it

Polished Concrete

Ground, densified and refined to a mechanical shine

Decorative Overlays

A new surface bonded to a sound slab

Saw-Cut Designs

Lines cut into the slab as pattern, not just as joints

Colored Concrete

Pigment through the mix, or hardened into the surface