Why Melton Driveways Crack, and What Actually Prevents It

If you have lived in Melton for more than a few years you have seen it: a driveway that looked perfect for three summers and now has a crack running across it, usually near the garage or somewhere near the middle.

It is rarely the concrete's fault.

The ground moves here

Melton sits on the Victorian Volcanic Plain. The soils are heavy clays, and heavy clays are reactive — they take on water and expand, then dry out and contract. Across a Melbourne western-suburbs year, with a wet winter and a genuinely hot, dry summer, that cycle is substantial and it repeats annually.

A concrete slab sitting on ground that rises and falls beneath it is being bent. Concrete is excellent in compression and poor in tension, so when it is bent far enough, it cracks. The question is never whether the ground will move. It is whether the slab was built to cope.

Which cracks matter and which do not

**Hairline surface crazing** is a fine map-like pattern in the surface. It is cosmetic, usually caused by the surface drying faster than the body of the slab, and structurally irrelevant.

**Cracks along a control joint** are the slab doing exactly what it was designed to do. That is a success, not a defect.

**A straight crack across the slab away from any joint**, particularly one where the two sides are at different heights, indicates the ground beneath has moved and the slab could not accommodate it. That one matters.

**A crack that follows a service trench line** — often running from the street toward the house — means the trench was not compacted properly before the pour.

What actually prevents it

**Excavation and base.** Getting down to competent material and building back with a properly graded, properly compacted crushed rock base. Compaction happens in layers; dumping the lot and running a plate over the top is not compaction.

**Reinforcement placed correctly.** Mesh does not stop cracks forming — it holds the slab together across them so they do not open and step. Mesh lying on the ground because nobody used bar chairs does nothing at all. Where it sits in the slab matters as much as whether it is there.

**Control joints, cut early and spaced right.** Joints are deliberate weak lines that tell the slab where to crack. Spacing them correctly for the slab thickness and cutting them early — before shrinkage stresses have built — is what keeps cracks in the joints and out of the middle of your driveway.

**Curing.** Concrete does not dry, it reacts, and it needs moisture to do so. A slab poured on a hot windy Melton day and left uncovered loses surface water fast and ends up weaker at the top than it should be.

**Drainage.** Anything that keeps the moisture content under the slab more stable — falls that move water away, sensible garden bed placement, downpipes not discharging alongside the driveway — reduces how far the clay swings between wet and dry.

If your driveway is already cracked

A tight crack with no height difference can be cut, sealed and largely forgotten. A crack where one side has lifted relative to the other is a ground problem, and filling it treats the symptom — it will reopen. Multiple stepped cracks across a slab usually mean the base was inadequate, and replacement is the honest answer.

Repouring with the same detail as the failed slab gets the same result in another decade.