You noticed one crack the week you moved in. Now that you look properly there are cracks everywhere, running between the joints, branching off the garage corners, a fine web across one panel that only shows up after it rains. Every time you pull in, you wonder whether the whole driveway is on its way out and you just haven't been told yet.
Usually it isn't. Concrete cracks, and a driveway with a lot of cracks is often a perfectly sound driveway that was never going to look like the day it was poured. Counting them won't tell you much. The useful questions are whether the two sides of each crack still line up and whether it's any wider than last year, and you can answer both yourself with a pencil and a board.
How many cracks is too many?
How much concrete cracking is normal/allowable before concern?
There's no set number, because the count matters far less than what the cracks are doing. Cracks that are thin, level on both sides and not growing are normal shrinkage and are cosmetic, however many there are. Be concerned when one side of a crack sits higher than the other, when cracks are widening year to year, or when the slab has broken into small loose pieces.
Why a driveway ends up with so many cracks
There's an old line among concrete finishers that the only two things you can guarantee about concrete are that it gets hard and it cracks. It's mostly true. Concrete shrinks as the water in the mix leaves it, and a slab that shrinks has to crack somewhere. The joints cut across a driveway are there to choose where, so the slab cracks in a straight line at the bottom of a groove where nobody notices.
When there are cracks between the joints as well, it usually means the joints were spaced too far apart or not cut deep enough for the slab to break along them, so it picked its own lines. That's a flaw from the day of the pour and it's cosmetic. Those cracks tend to appear in the first year or two, run fairly straight, and then stay put. We see driveways with a dozen of them that are still structurally fine twenty years on.
Denver adds its own reasons on top. Around a hundred freeze-thaw cycles a year open and close every crack a little, and the clay under much of the metro swells when it's wet and shrinks when it's dry, so a slab on a thin base gets pushed around more than it would elsewhere. That's why the same crack can look worse every spring, and it's why the next part matters.
What the pattern is telling you
Different crack patterns have different causes, and once you know which you're looking at, most of the worry either goes away or gets very specific.
A fine web of cracks across the surface, like crazing on old china, is a finishing or curing problem from the original pour. It sits in the top sliver of the slab, often only shows when the surface is wet and drying, and doesn't go any deeper. People describe it as spiderweb cracks over the whole surface, and it looks far worse than it is.
Straight cracks running across a panel between joints are shrinkage cracks. Diagonal cracks that start at an inside corner, like where the driveway meets the garage apron or wraps around a step, are corner cracks. Corners concentrate stress and they crack in almost every slab. Both of these are cosmetic as long as the two sides stay level.
The patterns worth taking seriously look different. Cracks that come together and break a panel into several small loose pieces, a crack where one side has dropped, or cracks along the outside edge where the edge itself is sagging all mean the ground underneath has changed. Edge cracking in particular often points to water getting under the slab from a downspout or a low spot in the yard, and the concrete repair on those starts with where the water comes from.
Three checks that settle it
Start with whether the crack is level. Run your shoe across it, or lay a straight board across it, the same board test we went through in how to tell whether concrete should be repaired or replaced. If both sides are flush, the slab is still where it was poured.
Then find out whether it's growing. Take a pencil or a marker and put a short line across each end of the cracks that worry you, write the date beside it, and take a photo with a coin next to the crack for scale. Look again in the spring. A crack that hasn't run past its marks or opened up is done moving. A crack that has, especially one that's wider after a winter, is still being pushed by something, and it's often the clay doing what's described in why concrete looks fine in October and terrible in April.
The last thing to look at is what's coming out of it. Weeds growing in a crack only mean it's been open a while. Soil or fine grey mud washing out after rain, or a hollow sound when you tap beside it, means water is moving material out from under the slab, and that's a base problem.
If every crack passes all three checks, you have an old, cracked, sound driveway. The useful thing to do is keep water out of the cracks so winter doesn't widen them, and a narrow level crack is a job you can do yourself with the right product, which is covered in whether you can fill cracks with a tube from the hardware store. A good sealer over the whole slab on a two to three year cycle does the rest.
When cracks everywhere really does mean replacing it
Sometimes it does. One homeowner described a driveway from the 1940s as all cracked up into dozens of pieces, and at that point there are no panels left to save and no repair that holds. The same goes for a slab where most of the panels sit at different heights, or one that sends water back toward the garage or the house, because no repair changes the slope a slab was poured at.
Between those two ends is the most common case, a driveway where most of it is fine and two or three panels have moved or broken up. Those panels get cut out at the joint, the base under them gets dug out and compacted, and new concrete goes back in that spot while the rest stays. New concrete won't match old concrete on day one, but it weathers toward it over a few seasons. When it does have to be the whole slab, removal and replacement is about the base and the drainage as much as the new concrete, since new concrete on the same ground cracks the same way.
What to do with it this fall
It's late October, and the window for filling cracks with anything that needs to cure is closing. Fill the narrow level ones on the next dry, mild afternoon if you can, and leave the rest until spring rather than rushing a product into cold concrete. Mark and photograph the cracks you're unsure about so you have something to compare against in April. Point downspouts away from the slab so less water gets under it this winter.
If you'd rather not guess, take a photo of the whole driveway from the street and a close one of the worst crack with a coin beside it, and call us at (720) 782-8086. We'll come out, check which cracks have moved and which haven't, find the cause of the ones that matter, and give you a written, itemized price. Most of the time the answer is repairing a few panels and leaving the rest alone, and we'll tell you when that's all it needs.