Concrete driveway crack repair on the Central Coast.

Start with a ruler, not a tube of filler.

Most Central Coast driveways have at least one crack. Concrete shrinks as it cures, slabs move slightly with moisture and temperature, and wheels repeatedly load the same tracks. The useful question is whether the crack is stable, still moving, or showing that the base beneath the slab has failed.

Clean a short section, measure the widest opening and run a straightedge across it. Mark the ends with a pencil and date the mark. Take a close photograph with a ruler in frame, then compare it after heavy rain and again after a dry spell. That simple record is far more useful to a quoting contractor than saying the crack has been there for years.

Four common crack patterns and what they mean.

• Fine random lines under about 0.3mm: usually drying shrinkage or crazing in the surface paste. They are commonly cosmetic and can wait, provided the slab is not flaking or holding water.
• A straight crack running from an internal corner: often shrinkage that found the weakest route because a control joint was missing or too far away. If both sides remain level and the width is stable, it can usually be routed and sealed.
• A crack wider than about 3mm or with a height step of 5mm: possible base settlement, root pressure or washout. This needs diagnosis before any decorative coating. Filling the gap will not make the slabs level.
• Several cracks with pumping mud or water: drainage or sub-base failure. This is urgent because each vehicle pass moves water and fines out from below the concrete, making the void larger.

AS 3727.1 is the Australian Standard used as a reference for residential pavements, including joints, drainage and construction. It does not promise crack-free concrete. It does reinforce the basic principle that joint layout and a sound, drained base matter more than any filler applied after movement starts.

Why cracks behave differently across the Coast.

On low sandy ground around Woy Woy, Umina and Ettalong, poor edge drainage can wash fine material from beneath a slab. Around Gosford, Wyoming and the ridges behind Erina, cut-and-fill house sites can settle differently across the driveway. In leafy suburbs, roots and blocked stormwater lines add another variable. Near Terrigal, salt exposure attacks already-open edges, but salt alone rarely causes a slab to move.

Older homes commonly have plain concrete divided into large panels, while newer estates around Wyong often use coloured or exposed aggregate finishes. A visible repair is easier to accept on plain concrete. On decorative concrete, colour and aggregate matching may be impossible, so a whole-surface resurface can look better once repairs become extensive.

The right repair for each condition.

Stable narrow crack: mechanically open the top enough to remove weak edges, vacuum it clean, insert backing material if it is deep, then use a compatible flexible polyurethane or similar trafficable sealant. The repair will remain visible, but it can keep water and grit out while tolerating small movement.

Spalled crack edges: remove every loose piece and rebuild the shoulders with a polymer-modified repair mortar before sealing. Smearing mortar over dust creates a thin feather edge that breaks under tyres. Repairs usually need a defined edge and the minimum thickness stated by the product manufacturer.

Moving or stepped crack: investigate drainage, roots and the sub-base first. Local slab lifting, partial panel replacement or reconstruction may be required. A rigid epoxy can be useful for a genuinely dormant structural repair, but it is a poor choice across a joint that still opens and closes.

Widespread map cracking and delamination: test whether only the surface is unsound. If the body of the slab is stable, grinding plus a bonded overlay may be economical. If panels rock, pump water or have multiple displaced fractures, replacement is usually the honest answer. Our sealing versus resurfacing guide explains that decision line.

Realistic 2026 repair costs.

A prepared flexible repair to a stable crack commonly runs $25 to $60 per linear metre. Deeper moving-joint work is more like $60 to $140 per linear metre. Small isolated jobs often have a $350 to $650 minimum charge because the contractor still has travel, grinding, dust control, setup and sometimes a return visit.

Local spall repairs are commonly $80 to $180 each, while broader surface repair can reach $70 to $140 per square metre before a coating. A 60m² driveway with several stable cracks, proper cleaning and a penetrating seal often totals $900 to $1,800. If a panel must be removed and repoured, allow roughly $180 to $320 per square metre for accessible residential work, with demolition, reinforcement, thickness and concrete volume moving the figure. Compare those numbers with the site’s full driveway sealing cost guide.

There is no general NSW or Central Coast Council rebate for routine private driveway crack repair or sealing. Disaster assistance may occasionally cover access needed to make a damaged home safe, but cosmetic external work is normally excluded and eligibility must be checked against the particular event.

What you can safely do yourself.

Homeowners can clean a crack with a stiff brush, photograph it, measure it and stop roof or garden water discharging beside the slab. A small stable crack can be filled if you follow the product data sheet, keep the material below the tyre surface and use gloves and eye protection. Do not grind unknown old coatings without suitable dust control, inject material beneath a slab, or try to jack a panel with improvised equipment.

Do not hose grinding slurry, degreaser or concrete residue into the gutter. Under the NSW Protection of the Environment Operations Act 1997, polluted runoff must not enter stormwater. On this coast, that drain can discharge to Brisbane Water, Tuggerah Lakes or the ocean without treatment.

How to read a crack-repair quote.

A good quote identifies the crack length, preparation method, repair product, expected visibility, cure time and the coating that will go over it. It says whether cracks are considered dormant or moving and excludes structural movement it cannot warrant. It also separates optional resurfacing from essential repair, so you can see what protects the driveway and what only improves appearance.

Be cautious when a quote simply says “fill cracks”, promises they will become invisible, or applies the same rigid filler to every line. Ask who controls wash water, how existing sealer compatibility will be checked, and how long vehicles must stay off the repair. For the best local weather window, use the Central Coast sealing calendar.