How to tell your driveway needs sealing, on the Central Coast.

Start with the water-drop test.

Tip a cup of water onto the driveway. If the water beads up and sits there, the seal is still working and you can stop reading. If it soaks straight in and leaves a dark patch that takes minutes to fade, the seal is gone and the concrete is drinking everything that lands on it, including salt. That test takes ten seconds and it is more reliable than any date on a calendar, because a driveway under a shade sail at Erina and a driveway facing the surf at Terrigal age at completely different rates.

Do it in three spots: the wheel tracks, the shaded edge and the section nearest the road. They fail in that order, and a driveway is rarely uniform.

Sign 1: it goes dark when it rains.

The first honest sign, and the earliest. An unsealed or worn slab darkens noticeably when wet and takes an hour to lighten back up. A sealed one stays close to its dry colour and dries within minutes. If you have started noticing your driveway looks like a different colour after a shower, the seal went a while ago.

Sign 2: moss or algae on the shaded strip.

This is the most common early sign on this coast. Moss and algae need a porous, damp surface to grip. A sealed slab sheds water and dries fast, so it stays clear. If the shaded southern strip of your driveway in Erina or Narara goes green every winter, the concrete is holding moisture, which means the seal has worn off there first. People scrub it, it comes back next June, and they scrub it again for five years without ever asking why it grips there and nowhere else.

Sign 3: a chalky white bloom near the kerb.

Now we are into the coastal-specific damage. Salt damage on a Central Coast driveway starts as a chalky white bloom on the surface, usually worst near the kerb and on the windward side where onshore spray lands and dries. It looks like the concrete is sweating powder. That is salt crystallising inside the pores and pushing outward, and it is the last cheap moment to act.

Sign 4: the top layer is flaking off.

After the bloom comes the scaling: the top few millimetres begin to flake off in coin-sized patches. Once it starts it accelerates, because every flake exposes fresh porous concrete for the next round of salt to get into. Caught at the bloom stage it is a clean and seal job. Left two more years it becomes a resurface. There is a full breakdown of what causes it and how it is repaired on our salt scaling repair page.

Sign 5: dust on your shoes.

Run a hand across the slab on a dry day. If it comes back with fine grey powder, the cement paste at the surface is breaking down. Dusting means the surface has lost its skin, and a slab that is dusting will absorb a sealer unevenly, so this is the point where we start needing extra prep and the quote starts climbing.

Sign 6: stains that used to wash off, do not.

Oil drips, red wine, the rust ring off a wheelie bin, tannin from spotted gum and jacaranda leaf drop. On a sealed driveway these sit on top and come off with a hose and a brush within a day or two. On a bare one they wick into the pores in hours and become permanent. If your driveway has started collecting a permanent record of everything that has ever been parked on it, the seal is gone. Tannin staining is enormous on this coast, the leaf litter under a mature gum will tea-stain bare concrete within a single autumn.

Sign 7: dull, pale, popping aggregate.

Exposed aggregate is meant to look wet and rich. When it goes pale, chalky and dusty underfoot, the topical sealer that was re-wetting the stone has worn through, usually at four to six years on this coast. Worse, loose stones start popping out because the cement matrix holding them is no longer protected. Reseal at the dull stage, not at the popping stage. Once stones are lifting, you are into repair work before the coat. See exposed aggregate sealing.

Sign 8: paver joints washing out.

On a paver driveway the tell is not the paver, it is the gap. If the jointing sand has dropped 5mm below the paver top, or you can see sand fanned across the kerb after every downpour, the joints are no longer stabilised. Pavers then start rocking under a wheel, and rocking pavers chip their own edges. Down on the sandy Woy Woy peninsula this happens faster than anywhere else on the Coast. See paver sealing for how a joint-stabilising seal fixes it.

What it costs to act early versus late.

This is the whole argument in one paragraph. Catching it early is roughly five to ten times cheaper. A plain concrete penetrating reseal is $6 to $11 per square metre, so a 60m² driveway is around $400 to $700 including the pressure clean, degrease and minor prep. Leave the same driveway until it is scaled, stained and pitted and you are into resurfacing at $45 to $90 per square metre, which is $2,700 to $5,400, or a full demolition and re-pour beyond $9,000.

Worked example. A Wyong home, 65m² of plain concrete, ten years old, never sealed. It is dusting in the wheel tracks, green down the shaded edge and has two oil rings. The job is a pressure clean, a moss treatment, two degreased spots and a chloride-resistant penetrating seal: about $700 to $1,100 at 2026 rates, one day on site. The identical driveway five years later, once the scaling has started, is a resurface at $2,900 to $5,850 and three days. Same house, same slab, five years of doing nothing.

The honest bit.

Not every driveway that looks tired needs sealing. Plenty of the driveways we are called to just need a good clean, and we will tell you that and charge you for a clean. And a driveway that is already structurally cracked through, heaving over a tree root or sinking at one corner does not get fixed by a sealer, no matter what anybody quotes you. Sealing protects sound concrete. Working out which one you have is the entire point of the free measure. For the timing side of it, see how often to reseal on the Central Coast.

Warning-sign questions.

How do I tell if my driveway needs sealing?

Tip a cup of water onto it. If the water beads up and sits there, the seal is still working. If it soaks straight in and leaves a dark patch that takes minutes to fade, the seal is gone and the concrete is drinking everything that lands on it, including salt. That water-drop test takes ten seconds and it is more reliable than any date on a calendar.

What does salt damage look like on a Central Coast driveway?

It starts as a chalky white bloom on the surface, then the top few millimetres begin to flake off in coin-sized patches, usually worst near the kerb and on the windward side. That is chloride-driven scaling. Once it starts it accelerates, because every flake exposes fresh porous concrete. Caught at the bloom stage it is a clean and seal job. Left two more years it becomes a resurface.

Is moss or green growth a sign my driveway needs sealing?

Yes, and it is the most common early sign on this coast. Moss and algae need a porous, damp surface to grip. A sealed slab sheds water and dries fast, so it stays clear. If the shaded southern strip of your driveway in Erina or Narara goes green every winter, the concrete is holding moisture, which means the seal has worn off there first.

Does a dull or faded exposed aggregate driveway need resealing?

Almost certainly. Exposed aggregate is meant to look wet and rich. When it goes pale, chalky and dusty underfoot, the topical sealer that was re-wetting the stone has worn through, usually at four to six years on this coast. Worse, loose stones start popping out because the cement matrix holding them is no longer protected. Reseal at the dull stage, not at the popping stage.

How much does it cost if I catch it early versus leave it?

Catching it early is roughly five to ten times cheaper. A plain concrete penetrating reseal is $6 to $11 per square metre, so a 60 square metre driveway is around $400 to $700 including the pressure clean, degrease and minor prep. Leave the same driveway until it is scaled, stained and pitted and you are into resurfacing at $45 to $90 per square metre, which is $2,700 to $5,400, or a full demolition and re-pour beyond $9,000.