Spray on concrete vs exposed aggregate is a question worth answering carefully because the two finishes are not really equivalent choices. Spray-on is primarily a resurfacing option applied over an existing slab; exposed aggregate is most commonly a new-pour choice where stone is seeded into fresh concrete. If you are resurfacing a driveway, spray-on is almost always the default. If you are pouring from scratch, exposed aggregate is a genuine contender. Our concrete finishes guide sets out all the options in one place. This guide focuses on how the two compare for a Central Coast driveway.
What each finish is, in one paragraph
Spray-on concrete is a polymer-modified cementitious overlay sprayed through a hopper gun onto an existing slab. The texture comes from the aggregate in the mix and the spray pattern. Colour is integral to the mix or applied as a sealer. The result is a new surface layer bonded to the old slab.
Exposed aggregate is concrete where the surface mortar is washed or brushed away while still fresh to reveal the decorative stone below. The stones are either present in the original mix or seeded on the surface after pour. This is a new-pour technique: you are not applying it to an existing surface, you are creating the surface as part of the concrete placement.
There is an exposed aggregate cap overlay product that replicates the look on existing slabs, but it is a different product family from a genuine exposed aggregate pour and should be treated as such.
Visual difference: texture, colour range and street appeal
Spray-on concrete offers a wide colour range through integral pigments and coloured sealers. The texture is consistent across the surface, with a stippled appearance that reads as a uniform field from the street. Modern spray-on systems can achieve sophisticated neutral palettes, from warm sandstone and charcoal through to off-white and slate.
Exposed aggregate is defined by the stone. The colour is determined primarily by the aggregate species chosen: bluestone chips, granite, river pebble, recycled glass. The result is a naturally varied, textured appearance with visible stones sitting proud of the surface. From the street, exposed aggregate has a richer, more complex visual texture than spray-on.
For street appeal, exposed aggregate tends to suit homes where natural materials dominate: timber weatherboard, stone cladding, face brick. Spray-on suits a wider range of home styles, particularly rendered exteriors and contemporary designs. Our spray-on concrete vs stencil concrete comparison covers the broader finish landscape.
Underfoot grip and barefoot comfort by the pool
Exposed aggregate has high intrinsic grip because the stone surface is rough. Wet or dry, bare feet on exposed aggregate do not slide. The trade-off is that the texture is unforgiving underfoot: bare feet on coarse stone for extended periods, particularly around a pool, can be uncomfortable for children.
Spray-on has a smoother stippled texture. Properly specified with a grip additive in the sealer, it performs well on driveways and is more comfortable underfoot around pool areas. The trade-off is that grip is partly dependent on sealer maintenance; a worn or resealed-with-gloss surface loses grip faster than aged exposed aggregate.
For pool surrounds, many homeowners choose spray-on with a fine texture for the comfort advantage. For driveways where grip and low maintenance are the priority, exposed aggregate’s natural roughness is an advantage.
How each finish ages under Coast salt air
Both finishes are vulnerable to salt air over time, but the failure modes differ. On spray-on, salt air attacks the sealer first, then the overlay bond. Without regular resealing, the colour fades and the surface begins to lift at edges and expansion joints. With proper maintenance, a spray-on finish on the Coast can hold well for twelve to fifteen years.
Exposed aggregate weathers differently. The sealer over the exposed stones eventually breaks down, and unprotected aggregate begins to absorb salt and moisture. On a beachfront property, this can cause the stones to pop or the mortar between them to erode. A worn exposed aggregate driveway near the ocean can look very tired by ten to twelve years without resealing.
Our guide on salt air damage to concrete driveways covers the chemistry in more detail. Both finishes need regular sealing on the Coast; the interval shortens the closer you are to salt water.
Resurfacing over existing exposed aggregate: yes or no
This is one of the most common questions about the two finishes: can spray-on go over an existing exposed aggregate driveway?
The short answer is yes, with preparation. The stones proud of the surface need to be diamond-ground back to a flatter profile before the overlay can be applied evenly. If the existing aggregate has loose stones, pop-outs or delaminating sections, those need to be stabilised or repaired. The grind creates both the flat base and the mechanical key for the new overlay to bond to.
The resulting surface is a spray-on finish over a slightly thicker substrate than a flat slab would provide. Done correctly, the result is clean and long-lasting. Done poorly, without adequate grinding, the stone texture telegraphs through the overlay as an uneven surface. See our exposed aggregate driveway resurfacing guide for more on that process.
Cost side by side for a typical driveway
For a resurfacing project on an existing slab, the comparison is straightforward.
| Finish | Typical application | Indicative cost/m2 | Notes |
|---|---|---|---|
| Spray-on (standard) | Over existing slab | $60-$90 | Grind + overlay + sealer |
| Spray-on (over aggregate, extra grind) | Over existing exposed agg. | $75-$100 | Additional grind to flatten stones |
| Exposed aggregate cap overlay | Over existing slab | $85-$120 | Seeded aggregate overlay, not a full pour |
| New exposed aggregate pour | Full replacement | $150-$250+ | Slab removal + new pour; not resurfacing |
A new exposed aggregate pour is a full concrete replacement job, not a resurfacing job. If a contractor quotes “exposed aggregate” at a price similar to a resurfacing job, clarify whether they mean a cap overlay or a new pour. They are completely different projects. See our driveway resurfacing service for what resurfacing includes.
Which one suits a new-build vs an older home
For a new build where the driveway is being poured as part of construction, exposed aggregate is a straightforward choice with no resurfacing premium. The aggregate is chosen to suit the home and the stone is seeded into the fresh concrete. No overlay is needed.
For an existing home with an aged concrete driveway, spray-on resurfacing is the practical solution. It restores appearance, provides a new surface layer and avoids the disruption and cost of a full slab replacement. An exposed aggregate look on an existing slab means an overlay product, not a genuine pour-and-wash technique.
For either scenario, contact us for a free on-site assessment and we can advise which approach suits your specific slab.
FAQs
Can I get an exposed aggregate look without replacing the whole driveway?
Yes, through an exposed aggregate cap overlay. A decorative aggregate is seeded into a fresh overlay and the surface is washed before the overlay fully sets to expose the stone. It is not identical to a genuine poured exposed aggregate finish, but it provides a similar visual result at a fraction of the cost of slab replacement.
Which finish is better for a steep driveway?
Exposed aggregate, or a spray-on with a grip additive, both perform well on grades. A smooth spray-on with a gloss sealer is the worst choice on a steep driveway. For steep grades, mention it specifically to your contractor so the finish and sealer are specified for grip rather than appearance.
Does spray-on concrete add height to the driveway?
Yes, by a small amount. A typical overlay is 10-20 mm thick depending on the product. This is usually not significant at a garage threshold or front gate, but it is worth confirming if there are tight height clearances.
How long does each finish take to apply?
For a typical double driveway, spray-on takes one to two days including prep. An exposed aggregate overlay is similar. Cure time before vehicle use is typically 5-7 days for either, though a contractor may allow foot traffic earlier. Follow your contractor’s cure schedule rather than relying on a general figure.
Which finish is easier to keep clean?
Spray-on with a quality sealer is generally easier to clean because the surface is more uniform. Exposed aggregate collects debris between the stones and can be harder to sweep clean. Both benefit from periodic pressure washing, but spray-on generally needs less effort.