One question decides it: is the slab still structurally sound? If the concrete is intact and only the surface has given up, resurfacing gives you a new driveway for a fraction of the price. If the slab is moving, or the base beneath it has failed, an overlay is money spent on hiding a problem that will reappear.
Here is how to tell which situation you are in, and what each option actually involves on an island where disposal means a barge trip.
What resurfacing actually involves
Resurfacing means bonding a new layer onto the existing slab. The old concrete stays where it is and becomes the base for a fresh surface.
What replacement involves
The work is mostly preparation. The existing surface has to be mechanically opened up, usually by diamond grinding, so the overlay has something to key into. Any cracks need stabilising. Then the topping goes down and is finished — plain, stamped, coloured or textured — and sealed.
When resurfacing is the right call
Replacement means breaking out the existing slab, carting it away, digging out and rebuilding the base beneath, and pouring a new driveway from scratch.
- Worn or dull surface with the slab itself intact.
- Staining from oil, leaves or general weathering.
- Fine crazing — shallow map-like surface cracking that is stable.
- Dated appearance you simply want to change.
It is a much bigger operation, and on Waiheke the disposal side is a real cost because the broken concrete has to leave the island. The advantage is that you get to fix whatever caused the original failure, which is the entire point when the base has gone.
When only replacement will do
When the slab underneath is sound and the complaint is cosmetic.
- Cracks that are widening rather than sitting stable.
- Sections at different heights, indicating the slab has broken into pieces that move independently.
- Spalling with rust staining, which means the reinforcement is corroding and expanding.
- Cost: resurfacing is a fraction of replacement, and more so where access is difficult.
In these cases the structure is doing its job and only the surface has aged. Resurfacing addresses exactly that, and you keep the base, the reinforcement and the levels you already have.
The two side by side
When the slab has stopped behaving as one piece.
| Resurfacing | Replacement | |
|---|---|---|
| Cost | A fraction of a rebuild | Includes break-out, disposal, base and new pour |
| Disruption | A few days, no demolition | Longer, with machinery and rubble off the island |
| Lifespan | Years, tied to the slab beneath | A full new slab life of 30 to 40 years |
| Right when | Slab sound, surface worn or dated | Slab cracked through, settling, or base failed |
How we work out which you need
These symptoms point at the base, the reinforcement, or both. Laying a new surface over a failing structure buys you perhaps a season before the same cracks come through, and you will have paid for the overlay as well as the replacement you ultimately need.
Not sure? Send us photos
By looking underneath rather than at the surface. We check whether cracks are active, whether sections have moved relative to each other, what the drainage is doing, and whether there is any sign of reinforcement corroding. Only then is it possible to say honestly which option your concrete warrants.