Resurfacing is substantially cheaper than replacement, so most people start there and hope. That is the wrong way round. The question is not what you would prefer to spend, it is what the slab in your driveway can actually carry. Here is how to work that out before anyone quotes you either one.
What each one actually is
Resurfacing bonds a thin cement-based overlay, usually a few millimetres, over the existing slab. The old concrete stays in the ground and keeps doing the structural work. You get a new surface, in days, without demolition or disposal.
Replacement breaks the slab out, hauls it away, re-prepares and re-grades the base, forms and pours new concrete, and then waits for it to cure. Most of that cost is removal, disposal and base work, not concrete, which is why the gap between the two is so large.
The four things to look at on your own driveway
You can do a reasonable first assessment yourself in ten minutes on a dry day.
- Displacement. Run your hand or a straightedge across each crack. If one side sits noticeably higher than the other, the slab has moved, and something under it moved first. That is a base problem, and an overlay will crack along the same line.
- Crack width and pattern. Fine, tight, map-like crazing across the surface is a surface issue and resurfaces well. A few wide cracks running the full width in straight lines usually means movement.
- Hollow sound. Tap around with a hammer or drag a heavy chain. A dull, hollow note means the concrete has delaminated from itself underneath. That area needs removing, not covering.
- Drainage. Look at it during real rain. Water pooling in the middle, or running toward the house rather than away, is a grading problem. An overlay follows the existing grade, so if the grade is wrong, resurfacing keeps it wrong.
When resurfacing is the right call
Sound slab, no displacement, no hollow areas, drainage acceptable, but the surface is spalled, stained, dusting, crazed or just ugly. This is the majority of tired residential driveways on the South Island, especially where the damage is from salt and freeze cycles working on the top few millimetres rather than from ground movement.
You also get options you would not get from a plain replacement pour: broom, trowel, stamped or stencilled finishes, and colour. On a patio that matters as much as durability.
When replacement is the right call
Sections at different heights. Cracks with displacement. Large hollow or crumbling areas. Water running toward the foundation. A slab that was poured too thin for what now parks on it. Tree roots that are still growing.
In those cases an overlay is money spent twice, because in a couple of winters you will be looking at the same problem plus a wasted layer on top of it. We do not do replacement work, which is precisely why we have no reason to talk you out of it. If that is what your driveway needs, we will say so at the assessment.
The middle ground nobody mentions
Partial replacement plus resurfacing is often the honest answer on a long driveway. One failed section comes out and gets repoured, the rest gets repaired and overlaid, and the whole thing finishes as one continuous surface. It costs more than an overlay and far less than a full replacement, and it puts the money where the actual problem is.
If your driveway is asphalt rather than concrete, none of the above applies and you are looking at sealcoating or resurfacing on the asphalt side instead. Full detail on the concrete side is on the concrete resurfacing page.