Why Is My Concrete Driveway Cracking? Spokane Causes, Control Joints and Which Cracks to Worry About (2026)
Short answer: most cracks in a Spokane concrete driveway come from shrinkage, and a few come from the ground underneath moving. Concrete always shrinks as it sets and dries, and if the slab can't move freely, it cracks. Control joints exist to make those cracks happen in straight lines where you want them. Cracks that wander between the joints, sink, or keep widening usually point to joint spacing, the base, drainage or our freeze-thaw winters.
Why concrete cracks at all
The National Ready Mixed Concrete Association (NRMCA) is blunt about it: cracks in concrete can't be prevented entirely, only controlled and minimized. Here's why:
- Concrete is weak in tension. When its natural shrinkage is restrained by the ground, the house or a garage slab, tensile stress builds until it cracks
- Early cracks come from setting. In the first hours and days, temperature changes and the slight contraction as concrete hardens cause most cracking
- Later cracks come from drying. NRMCA's drying shrinkage guide says this cracking usually shows up within days to several weeks after the pour
- Uncontrolled cracks are mostly cosmetic. NRMCA says irregular shrinkage cracks are unsightly but generally don't affect the integrity of the concrete
The five usual suspects
1. Joints too far apart or cut too late. NRMCA's guidance for slabs on grade:
- Spacing: no more than 24 to 36 times the slab thickness, which is about 10 feet for a 4-inch slab, and never more than 15 feet
- Panel shape: square or close to it, with the long side no more than 1.5 times the short side, and no L-shaped panels
- Depth: at least one quarter of the slab thickness, and never less than 1 inch
- Timing: conventional saw cuts within 4 to 12 hours after finishing, or early-entry cuts 1 to 4 hours after finishing. Wait too long and the slab cracks before the saw gets there
2. No isolation joint. NRMCA calls for full-depth isolation joints where a driveway meets the garage slab, a sidewalk, steps or a light pole, so each piece can move on its own. Cracks that start at a corner of the garage or a post are often this.
3. Plastic shrinkage on pour day. These are the short, roughly parallel surface cracks, usually 1 to 3 feet apart, that NRMCA says form when the surface dries faster than bleed water can rise. Wind over 5 mph, low humidity and heat all speed it up. They're shallow and rarely affect strength, but they can let water and deicers in.
4. A weak or wet base. NRMCA lists a uniform, well-compacted subgrade as one of the basics for preventing cracks. Soft spots, poorly compacted trench backfill, or water that sits under the slab let sections settle, and that's when one side of a crack ends up lower than the other.
5. Spokane's freeze-thaw winters. NOAA's 1991–2020 normals for Spokane International Airport show average lows below freezing from November through March. Water that gets into cracks or a saturated base freezes and expands, which widens cracks and flakes the surface. That's why NRMCA calls for air-entrained concrete on outdoor slabs exposed to freezing.
Does rebar or wire mesh stop cracking?
No. NRMCA's cracking guide says wire mesh and reinforcement in slabs can't prevent cracking. Placed at the right depth, reinforcement can keep cracks tighter. Joints still do the main job of deciding where the cracks go.
Which cracks to worry about
- Usually cosmetic: hairline cracks, cracks running along or in line with a joint, and fine surface crazing
- Worth a closer look: cracks wider than a hairline, cracks where one side sits higher than the other, cracks that keep growing each spring, and pieces that rock or sink
- Fix the cause, too: downspouts dumping onto the slab, water running under the edge, and a missing isolation joint at the garage keep the problem coming back
Our driveway repair vs. replacement guide walks through when patching or sealing a crack makes sense and when a section should come out.
How we pour driveways to crack less
- Base first: compacted gravel on a firm subgrade, with the slab sloped to drain away from the house
- Air-entrained mix: for freeze-thaw and deicer exposure
- Joints on a plan: spaced to the slab thickness, panels kept close to square, saw cuts made on time, and isolation joints at the garage, walks and steps
- Curing: NRMCA recommends starting curing as soon as possible, with a curing compound or wet covering kept moist for at least 3 days
- Winter care: no deicers on new concrete its first winter, and a breathable sealer once it's dry. Our concrete sealing guide and winter concrete guide cover both
Get your driveway looked at
If your driveway is cracking, sinking or due for replacement, call Raven Buildings at 509-350-2016 or request a free quote and send a few photos. We pour driveways across Spokane County, including Mead, Deer Park, Liberty Lake and Cheney. See all of our concrete flatwork services.