Seal it or resurface it? A straight answer for the Central Coast.

The difference in one paragraph.

Sealing protects the concrete you already have. It is a coat that soaks in or sits on top and keeps salt, oil and water out. It does not change the shape of anything and, with a penetrating product, barely changes the look. Resurfacing replaces the top of the driveway with a new bonded layer, so it changes how the driveway looks as well as protecting it. Sealing is $6 to $26 per square metre, resurfacing is $45 to $90. The rule of thumb: if the surface is sound, seal it. If the surface has failed but the slab underneath is solid, resurface it.

The test: is the surface sound?

Forget how tired it looks. Look at whether the surface is intact. This one question decides the job and it is not a close call once you know what you are looking at.

• Seal it: stains, dullness, moss, faded colour, water soaking in instead of beading, tannin tea-staining, oil rings. The concrete is fine, it just has no armour.
• Resurface it: flaking, pitting, exposed sand and stone, a surface that dusts grey on your hand, popped aggregate, chunks missing at the kerb. The top layer has broken down and a sealer has nothing sound to grip.
• Neither, replace it: cracks wider than about 5mm, sections that have dropped or lifted, slabs that rock under a car, heave over a tree root. The base has moved and no surface treatment fixes movement.

The line that matters: sealing a scaled driveway just gives you a shiny scaled driveway. We say this constantly and people are always surprised, because someone has already quoted them a cheap seal on a slab that cannot hold one.

What sealing gets you.

A seal keeps chloride, oil, tannin and water out of the pores. On a plain concrete driveway a penetrating silane or siloxane at $6 to $11 per square metre is invisible, breathable, will not peel and lasts five to seven years back from the water. On decorative concrete a topical acrylic or polyurethane at $12 to $22 restores the colour and sheen. Pavers take a joint-stabilising seal at $9 to $18 that also locks the sand, and exposed aggregate takes a dedicated wet-look or matte coat at $14 to $26. Every one of those includes the pressure clean and degrease at $3 to $7 per square metre, because prep is most of what makes a coat last. Full detail is on our concrete sealing page and the product choice is worked through on our choosing a sealer guide.

What resurfacing gets you.

A resurface bonds a new decorative topping over the existing slab: spray-on or stencil at $45 to $75 per square metre, trowel-applied or stamped stone-look at $65 to $90. It buries a failed surface, and it is also the only way to turn plain grey concrete into something else without demolishing it. It comes sealed as part of the job, so you are not paying for both. It needs a structurally sound slab and proper preparation, and it takes about three days including cure rather than one. See driveway resurfacing.

When it is neither.

This is where an honest contractor earns their keep. When the problem is structural rather than skin deep, both answers are wrong. Cracks wider than about 5mm, sections that have dropped so one edge stands proud of the next, slabs that rock under a car, or heave from a tree root all mean the base has moved. A resurface over a moving slab will crack in the same place within a season, and you will have paid $4,000 to watch it happen. That is a demolition and re-pour to AS 3727.1, the residential pavements standard, generally $9,000 and up.

On the Coast we see three causes of that movement over and over. Reactive clay through the Erina and Narara valleys, which swells and shrinks with our wet-dry cycle. Sand and a high water table down on the Woy Woy peninsula, where slabs settle unevenly. And fig and gum roots, which will lift a 100mm driveway without any difficulty at all. Minor cracks, under about 2mm and not moving, are a different story: we repair them at $25 to $90 each and then seal over the top quite happily.

Salt changes the timing, not the rule.

Chloride-driven scaling on a beachfront driveway at Terrigal or Umina moves a slab from seal territory to resurface territory faster than anything inland. A white chalky bloom is still a clean-and-seal job. Once the top few millimetres are flaking off in patches it is a resurface, and on the beachfront that transition can take as little as two or three years from first bloom to failed surface. Inland at Wyong the same slab might take a decade. It is the same test, just on a faster clock. The mechanics are on our salt scaling repair page.

Three worked examples.

Point Clare, 60m², dull and stained, surface intact.

Fifteen-year-old plain concrete, never sealed, tannin stained under a gum, green down the shaded edge, but hard and sound underfoot. This is a seal, not a resurface. Pressure clean, moss treatment, degrease, penetrating coat: about $600 to $1,100, one day. Anyone quoting a resurface on this driveway is selling you $3,000 you do not need.

Umina Beach, 55m², scaled and pitting.

Twenty years of salt spray, the surface flaking in patches across the front third, dusting everywhere, but the slab itself is dead flat with no significant cracks. A sealer has nothing to bond to. This is a spray-on resurface: roughly $2,475 to $4,125, three days, and it comes out looking like a new driveway.

Narara, 70m², cracked and lifting.

A 12mm crack running the length of the drive with a 15mm step across it, and the top section rocking under a wheel. Reactive clay plus a large tree ten metres away. Neither a seal nor a resurface will hold. This is a re-pour, $9,000-plus, and we say so and walk away rather than take $5,000 for an overlay that will telegraph that crack back through by next autumn.

So which is worth it?

It depends entirely on what you want. If the driveway just needs protecting, resurfacing is roughly five times the price for no extra protection, so it is a waste. If the surface has actually failed, or you hate the look of your plain grey concrete and want a stencilled or stone-look finish, resurfacing is the only thing that delivers it, and it comes sealed. Both jobs need the same honest prep, and both are quoted free on site. The full rate card is on the pricing page and the numbers are broken down on our cost guide.

Seal or resurface questions.

What is the difference between sealing and resurfacing a driveway?

Sealing protects the concrete you already have, it is a coat that soaks in or sits on top and keeps salt, oil and water out. Resurfacing replaces the top of the driveway with a new bonded layer, so it changes how the driveway looks as well as protecting it. Sealing is $6 to $26 per square metre, resurfacing is $45 to $90. The rule of thumb: if the surface is sound, seal it. If the surface has failed but the slab underneath is solid, resurface it.

How do I know if my driveway is too far gone to just seal?

Look at whether the surface is intact. Stains, dullness, moss and a faded colour are all seal-and-clean problems, they look bad but the concrete is fine. Flaking, pitting, exposed sand and stone, and a surface that dusts on your hand mean the top layer has broken down and a sealer has nothing sound to grip, so it needs resurfacing. Sealing a scaled driveway just gives you a shiny scaled driveway.

When is a driveway past resurfacing and needs replacing?

When the problem is structural rather than skin deep. Cracks wider than about 5mm, sections that have dropped or lifted so one edge stands proud of the next, slabs that rock under a car, or heave from a tree root all mean the base has moved. A resurface over a moving slab will crack in the same place within a season. That is a demolition and re-pour, generally $9,000 and up, and we will tell you so rather than sell you an overlay that will fail.

Is resurfacing worth it compared to sealing?

It depends entirely on what you want. If the driveway just needs protecting, resurfacing is roughly five times the price for no extra protection, so it is a waste. If the surface has actually failed, or you hate the look of your plain grey concrete and want a stencilled or stone-look finish, resurfacing is the only thing that delivers it, and it comes sealed. Both jobs need the same honest prep, and both are quoted free on site.

Does salt damage on the Central Coast change the answer?

It changes the timing. Chloride-driven scaling on a beachfront driveway at Terrigal or Umina moves a slab from seal territory to resurface territory faster than anything inland. A white chalky bloom is still a clean-and-seal job. Once the top few millimetres are flaking off in patches it is a resurface, and on the beachfront that transition can take as little as two or three years from first bloom to failed surface.