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Resurfacing vs Replacing Concrete
One of these costs a fraction of the other and lasts just as long, in the specific circumstances where it applies. Outside those circumstances it is money spent twice. Here is the test that separates them.
Resurfacing has a reputation problem in this trade, and it is half deserved. Sold as a cheap alternative to replacement it disappoints reliably, because the situations it suits are narrower than the sales pitch suggests. Applied where it belongs, it is one of the better pieces of value in residential concrete. The difference is not the product. It is whether anyone checked the slab first.
What each one actually is
Resurfacing bonds a new layer onto concrete that stays where it is. The old slab remains the structure; the overlay becomes the surface you walk and drive on. Existing joints are carried up through it so the assembly keeps moving where it always moved.
Replacement takes the concrete out, deals with whatever is underneath, and pours again. It is the only route that lets anybody touch the base, which turns out to be the whole argument.
The test, in two parts
An overlay needs two things to be true at once. Not one. Both.
Is the concrete sound? Sound means the top layer is not coming away and the slab is not delaminating below the surface. Tapping across it tells you a surprising amount: a solid ring is good, a dull hollow note means the layers have already separated there and nothing will bond to it.
Is the ground still? This is the one people skip. Lay a straight edge across every joint and crack. Slabs sitting level with one another, nothing rocking underfoot, no step between two pieces. If anything has moved, the base is the problem, and an overlay does not go anywhere near the base.
Fail either test and resurfacing is the wrong purchase. It will look excellent for a season, then reproduce the fault it was laid over, and the eventual replacement now has an extra layer to remove.
When resurfacing is the right call
- Winter has taken the surface but not the slab. Flaking, pitting, exposed stone, over concrete that is otherwise level and solid. This is the textbook case.
- The finish was poor from the start. An uneven or badly closed surface on a structurally fine slab.
- You want a different look on sound concrete. Overlays can be coloured and patterned, which is the only route to a stamped appearance on a slab that already exists.
- The slab is young and the damage is superficial. Tearing out concrete with decades left in it because the top eight millimetres disappointed you is a poor trade.
When replacement is the only honest answer
- Anything has changed height. A step between two slabs, a bay that has dropped, a section that rocks. The fault is under the concrete.
- Cracks run through the full thickness and the two sides move independently.
- Drainage runs the wrong way. An overlay follows the existing profile, so a slab that sends water at the house will still send water at the house afterwards, now slightly higher.
- The slab was too thin or has no base worth the name. Adding a surface to a structure that was underspecified does not change what it is.
- It has already been overlaid once. Layers on layers is a maintenance pattern with a bad ending.
The question that decides most of these
How long do you want this to last, and are you still here for it?
Resurfacing a sound slab is not a compromise; the overlay wears out eventually and can be renewed, and in the meantime you have a good surface for much less money and much less disruption. There is no tear-out, no disposal, and the job is measured in days rather than in access being lost for a week.
Replacement resets the clock properly. New base, correct thickness, joints where they should be, drainage designed rather than inherited. It costs substantially more and it is the right call when the problem is underneath, when you intend to stay, or when the existing slab has simply run out of life.
What we will not do is put an overlay over a moving slab because it fits a budget. It is the one request in this trade where saying yes is worse for the customer than saying no, and the second conversation is always harder than the first.
What an overlay asks of you afterwards
Worth factoring in, because it is rarely mentioned at the point of sale. An overlay is a thinner wearing surface than a full slab, so it is less tolerant of the things that attack concrete from above. Deicing chemistry in particular has less material to work through before it reaches the bond line, and a scraped snow shovel or a plough blade catching an edge finds an overlay sooner than it finds a slab.
None of that makes resurfacing a bad choice. It does mean an overlaid driveway rewards the same first-winter discipline as a new one, and that the honest comparison is not simply price against price but price against how the surface will be treated.
Getting a straight answer out of a quote
If somebody proposes resurfacing, ask them two questions. What did you find when you checked for movement, and what happens at the existing joints. An answer that engages with both is a contractor who tested the slab. An answer about how good the product is, without reference to your concrete, is a product pitch.
Both routes live on our concrete repair page. For a driveway specifically, the bay-by-bay version of this decision, including when the count of failed panels tips the maths, is in repair or replace a concrete driveway. If the surface is the thing that has gone, why concrete scales and flakes explains what caused it.