Chicago Concrete and Sidewalk Repair: Start Here

Concrete repair in Chicago starts with a plain question: is this a cosmetic flaw, a drainage problem or a slab that has actually failed? Most cracks are cosmetic. Flaking surfaces are usually a freeze-thaw and salt story. A slab that sinks or heaves is a ground and water story. Each one has a different fix, and the wrong fix, such as a patch over a bad base, comes back within a winter.

This guide covers the whole topic for a Chicago property owner: sidewalks, steps and stoops, driveways, garage slabs and patios. It explains why concrete fails here, what a good job looks like, what permits and licenses apply, and how to hire a contractor. Each section links to a deeper article.

If you only read one part, read this:

1. Identify the failure. Hairline cracks are normal. Scaling, sinking, heaving and crumbling edges are not.
2. Find the cause before you fix the symptom. Water, salt, tree roots and poor base drive most failures.
3. Check whose surface it is. A slab on your property and a sidewalk in the public way follow different rules.
4. Hire for the details. Mix, joints, finishing and curing decide whether new concrete lasts through Chicago winters.

What does concrete work cover on a Chicago property?

Most owners meet concrete in one of six places. Each has its own article.

• Sidewalks: the public walk in front of the property, and the private walks beside and behind it. See sidewalk repair: fix, replace or wait.
• Steps and stoops: front and back concrete steps, often the first thing to crumble. See concrete steps: repair or replace and resurfacing concrete steps.
• Driveways and aprons: the slab on your lot and the apron that crosses the sidewalk to the street. See Chicago driveway permits and aprons and what drives driveway cost.
• Garage slabs: slab-on-grade floors that crack, sink or flake. See garage slab replacement.
• Patios, walkways and pads: private flatwork, usually the simplest category for permits.
• Basement walls and foundations: poured walls where cracking questions come up. See the foundation section in excavation and foundation repair.

Concrete and masonry are cousins. Brick, stone and concrete are all "masonry" in the City's permit rules, so some repairs fall under the same permit and license structure. Our Chicago brick and masonry repair guide covers the brick side.

Why does Chicago concrete crack, flake and sink?

Three forces do most of the damage: water, freezing and movement.

Freeze-thaw. Chicago's average year has roughly 121 days with a low at or below 32 F, and about 43 days when the high never gets above 32 F (NWS Chicago normals). The gap between those, about 78 days, is a rough proxy for mornings that start below freezing and warm above it. It is a derived estimate and not an engineering cycle count, but it shows how often wet concrete freezes and thaws here. We explain more in why Chicago concrete flakes.

Scaling. Scaling is the flaking of the surface from freeze-thaw exposure, and deicers make it worse by raising surface saturation and increasing the number of freeze-thaw cycles. NRMCA, the National Ready Mixed Concrete Association, lists the common causes: concrete without enough air entrainment, low-strength or permeable concrete, the wrong mix, too much deicer on new concrete, bad finishing and insufficient curing (NRMCA CIP 2). Note what that list says: scaling is mostly a quality problem in the original pour, not simply "salt rots concrete."

Popouts. Small cone-shaped cavities, about a quarter inch to a few inches across, happen when a near-surface aggregate particle freezes while saturated and fractures (NRMCA CIP 40).

Settlement and heave. A slab that sinks has lost the ground beneath it, often to poor compaction, washed-out soil or a drainage problem. A sidewalk that heaves is usually pushed up by tree roots, frozen ground or water. NRMCA says subgrade should be well compacted, topsoil and soft spots removed, and no concrete should ever be placed on frozen ground (NRMCA CIP 4). See why a sidewalk heaves and why a concrete stoop sinks.

Missing or poor joints. Concrete shrinks as it sets and dries. When the shrinkage is restrained, it cracks. Joints are "pre-planned cracks" that control where the cracking happens (NRMCA CIP 6). Most cracking traces back to design and construction practices: missing joints, poor subgrade, watered-down concrete, poor finishing, fast moisture loss and inadequate curing (NRMCA CIP 4).

Which cracks are normal, and which ones matter?

No concrete is completely crack-free. NRMCA says most random early cracks rarely affect structural integrity or service life, with two exceptions: D-cracking, which is freeze-thaw damage in some porous aggregates and starts at joints at the bottom of exterior slabs, and alkali-aggregate reaction (NRMCA CIP 4).

In practice, here is how we sort cracks on a walk-through:

NRMCA's guidance on poured basement walls says some cracking is normal from shrinkage, openings, pour lines and settlement. Typical builder warranties require repair only if cracks leak, show measurable vertical displacement or exceed 1/8 inch, and exterior waterproofing with drain tile around the footing is generally better than interior (NRMCA CIP 7). For repair, the American Concrete Institute lists epoxy injection under pressure as a potentially effective structural repair, with the crack clean and free of debris (ACI RAP Bulletin 1). Read which concrete cracks to worry about for the full breakdown.

Who deals with the sidewalk in front of the property?

The sidewalk is the one place where concrete work leaves your lot. It's also the place with the most confusion, so here is what we can say, and what we can't.

What we can say: work in the public way, which means the sidewalk, curb, alley or parkway, needs a permit from CDOT, the Chicago Department of Transportation. That permit is separate from the Department of Buildings permit. The same applies if you use the public way for scaffolding, dumpsters or materials (Guide to Building Permits). A mason license isn't required for brick or concrete sidewalks or concrete paving (Guide to Building Permits).

What we can't say: who is legally responsible for repairing a particular public sidewalk. We haven't confirmed that rule from an official City page, and the City's own Shared Cost Sidewalk Program page doesn't state it either (CDOT). If you need that answer for a specific case, ask CDOT or an attorney. Our article on who pays for a broken Chicago sidewalk walks through what the City does and doesn't say.

What the City does say: residents can report other sidewalk conditions through 311 (CDOT).

The Shared Cost Sidewalk Program

CDOT runs a voluntary program where owners share the cost of sidewalk reconstruction with the City. Key points, from CDOT's program information (CDOT):

• Applications go through 311 only, once a year, first come, first served, and funds are limited.
• You must reapply every year.
• CDOT surveys the property, decides the scope, then invoices. Payment in full goes to the Department of Finance before work proceeds.

It is not a flat 50/50 split. Owners pay a per-square-foot rate set by the City. Seniors 65 and over and persons with disabilities who are owner-occupants of non-commercial properties of four units or less can get a 50 percent discount. Corner lots pay for both sides. Only the portion CDOT judges in need of replacement gets program pricing, and custom, vaulted or private-property sidewalk isn't eligible (CDOT). Dates, funding and rules change every year, so confirm on CDOT's site. See Chicago's Shared Cost Sidewalk Program, explained.

If a sidewalk violation notice arrives

A sidewalk notice follows the same City process as other building cases: a hearing, a date, proof of the fix. See what to do with a Chicago sidewalk violation notice. If it's a trip hazard, the question is whether it can be ground or has to be replaced. See sidewalk trip hazards and grinding.

Do you need a permit to pour or repair concrete in Chicago?

For flatwork on private property, often no. For anything in the public way, yes. And some concrete repairs fall under masonry rules. Here is the structure:

Private flatwork: usually no building permit. The City's list says no permit is required for installing, altering or removing a noncombustible (concrete or brick) sidewalk, patio or walkway that is not in or on the public way, is not more than 30 inches above adjacent grade, and is not over any basement or story below (Guide to Building Permits). That 30 inch limit and the "not over a basement" condition matter for raised stoops and porches.

Driveways. The City lists no permit for in-kind replacement of a concrete, brick or asphalt parking surface or driveway, but a permit is required to establish, expand or eliminate off-street parking (Guide to Building Permits). The apron that crosses the public way is a CDOT matter. Anyone who owns or operates a driveway in Chicago needs a CDOT driveway permit, and the residential application asks for a plat of survey or sketch, a photo of the curb cut, apron and sidewalk, liability insurance naming the City, and zoning sign-off for new driveways (CDOT). See what CDOT requires for driveways.

Small masonry replacement. For residential buildings up to four stories, no permit is required for in-kind replacement of up to 50 square feet of masonry, defined as brick, stone or concrete (Guide to Building Permits).

Larger or structural concrete repair. The Express Permit program covers concrete repair up to 100 square feet without drawings and up to 5,000 square feet with drawings by an Illinois-licensed architect or structural engineer (Guide to Building Permits).

Everything else. The City's basic rule is that a permit is required before most construction and repair work, with a limited range of exemptions. Work done under an exemption must still comply with all codes (Guide to Building Permits). Scaffolding, dumpsters and materials in the street or alley need a separate CDOT permit (Guide to Building Permits). Permit rules are volatile. Check with the Department of Buildings before you start. Our full explanation is do you need a permit to pour concrete in Chicago.

Who is allowed to do concrete work?

Chicago's mason license applies to work in stone, concrete, terra cotta or structural tile (Chicago mason license). The exceptions include brick or concrete sidewalks, concrete paving, slab-on-grade foundations for single-story non-occupiable structures like sheds and garages, foundations for fences, decks and open porches, repairs that don't need a permit, and owners of a primary residence of three stories or fewer and six units or fewer, one property per calendar year (mason license exceptions).

That means sidewalk and driveway flatwork doesn't need a mason license, but a structural concrete repair that needs a permit does. In all cases, check licenses on the City's lookup (Department of Buildings), and read our explainer on the Chicago masonry license for the details. Akats is licensed and insured in Illinois and handles concrete in-house. See our concrete services page.

What does a well-made concrete job look like?

Most failures can be traced to what happened on pour day, which is why two slabs poured in the same year can age very differently. NRMCA's guidance for exterior slabs exposed to freezing and deicers gives a useful checklist you can ask a contractor about (NRMCA CIP 2):

• Strength: 4,000 psi specified strength.
• Air entrainment: about 6 percent total air for 3/4 inch or 1 inch aggregate.
• Slump: 3 to 5 inches, with no extra water added at the jobsite.
• Finishing: only after the bleed water is gone, avoiding steel trowels (a broom finish is enough).
• Curing: done properly, and a breathable silane or siloxane sealer can be considered.

Reinforcement and joints:

• Joints: NRMCA's guidance for control joints is a spacing of 24 to 36 times the slab thickness (about 10 feet for a 4 inch slab), a maximum of 15 feet, panels square or nearly so, and a joint depth of at least one quarter of the slab thickness and not less than 1 inch. Isolation joints go where slabs meet walls, footings, columns and stairs (NRMCA CIP 6). See why sidewalks have control joints.
• Reinforcement: wire mesh and rebar can't prevent cracking, but properly placed reinforcement reduces crack width and keeps cracks and joints from opening. Cover of at least 2 inches keeps salt and moisture off the steel (NRMCA).
• Base: compacted subgrade and no frozen ground. NRMCA also warns that a vapor retarder directly under a slab increases bleeding and greatly raises the cracking potential (NRMCA CIP 4).

Thickness is a code and design question. We don't state a standard thickness here because we haven't verified a City figure. See how thick a sidewalk should be and garage slab thickness for what we can and can't say.

Can you pour concrete in a Chicago winter?

Yes, with protection, and not carelessly. NRMCA says fresh concrete freezes if its temperature falls below about 25 F, and frozen fresh concrete can lose more than 50 percent of its potential strength and won't be durable. The concrete must be protected from freezing until it reaches 500 psi, about two days after placement (NRMCA CIP 27).

Key cold-weather practices (NRMCA CIP 27):

• Cold weather practice starts well above freezing. NRMCA's older definition is more than three consecutive days with an average temperature under 40 F, and the newer ACI wording applies whenever air temperature is below, or expected to fall below, 40 F during the protection period (NRMCA and STRUCTURE magazine).
• Recommended concrete temperature as placed is 55 F for sections thinner than 12 inches.
• Snow, ice and frost must be removed before placing, and surfaces in contact with the concrete must be above freezing (NRMCA).
• Don't let concrete cool faster than 5 F per hour for the first 24 hours, and cure with a moisture-retaining method, not wet curing, when freezing is expected (NRMCA).
• An accelerator doesn't prevent freezing. Calcium chloride is capped at 2 percent by weight of cement (NRMCA).

Concrete that will see freeze-thaw cycles while wet should be air-entrained, and should be protected from freeze-thaw until it reaches at least 3,500 psi. That's why a contractor who can't talk about winter protection shouldn't be pouring in December. See how concrete gets poured in a Chicago winter and what temperature is too cold to pour. Related: how long before you can walk or drive on new concrete.

Salt, sealers and the first winter

Deicers are the most common thing we see wrecking young concrete. NRMCA's guidance is straightforward (NRMCA CIP 2):

• Avoid deicers on new concrete in its first winter if you can. Use clean sand.
• Afterward, use moderate amounts. Sodium chloride and calcium chloride are considered acceptable for concrete.
• Never use ammonium sulfate, ammonium nitrate or magnesium-based salts.
• Hose off salt tracked in by vehicles when possible, and fix drainage that lets salt solution pool.

NRMCA also says light to moderate scaling can be resurfaced with a portland cement, latex-modified or polymer-modified repair mortar after removing unsound surface. A repair is only as strong as the base it bonds to and won't match the original color, and severe, progressing scaling may not be feasible to repair (NRMCA CIP 2). That's the honest answer to "can I just resurface it": sometimes, if what's underneath is sound.

Repair, resurface or replace: how to decide

Here is the decision tree we use, from least to most work:

1. Cosmetic only (hairline cracks, small popouts): leave it, or fill it, if water is entering.
2. Light scaling on a sound slab: resurfacing can work, after the failed surface is removed.
3. A single cracked or sunken section: cut out and replace that section, with a correct base and joints.
4. Widespread scaling, heaving, settlement or crumbling: replace.
5. A slab that sank but is otherwise sound: the question is whether the cause is fixed. See slab lifting versus replacement.
6. A step or stoop that is moving or pulling away from the building: treat it as structural until proven otherwise. See do concrete steps need footings.

For smaller jobs, some owners can handle a crack fill themselves. See what is DIY-safe on driveway cracks. For anything that carries people, such as steps and stoops, or sits at the public way, hire it out.

What drives the cost of concrete work?

We don't publish prices, because the same square footage can be a very different job. These are the real drivers:

• Demolition and haul-out. Breaking up old concrete and hauling it away.
• Base and drainage work. Fixing the subgrade, grading or a water problem under the slab.
• Access. Gangways, rear yards and tight alleys can't take a truck, which means hand work or pumping.
• Thickness, reinforcement and mix. Air-entrained, higher-strength concrete and added steel cost more than a thin, plain pour.
• Forms and finish. Curves, steps and special finishes take time.
• Season. Cold-weather protection adds materials and labor.
• Permits and public way costs. A CDOT permit for work at the curb or a dumpster in the street.
• Matching and tie-ins. Meeting an existing apron, steps or a neighbor's walk.

How do you hire a concrete contractor in Chicago?

Ask for these before you sign:

1. License and insurance, and confirm City licenses on the lookup (Department of Buildings).
2. A written contract. Illinois requires a signed written contract or work order for home repair over $1,000 on a residence of 1 to 6 units, stating total cost and materials (Illinois Home Repair and Remodeling Act). The Act lists driveways, porches and garages among its examples (Illinois General Assembly).
3. Who handles the CDOT permit, if any part touches the public way.
4. Mix and method: the strength, air content, joint plan, base prep and cure.
5. Winter plan, if the job runs from late fall to spring.
6. Photos of each stage, especially base and forms, since you can't see them after the pour.

Permits expire if the first inspection isn't passed within 540 days of when work may begin (Guide to Building Permits), so don't let a permitted job sit.

When should you call us?

Call when you see a step or stoop that moves, a sidewalk trip hazard, a slab that has sunk or heaved, scaling that is spreading, or a notice from the City. We can look at the surface, the base and the water, give you a written estimate, and tell you if it's simple enough to fix yourself. Call 312-339-9627 or request a free estimate, in English or Spanish.

If a City notice names concrete, our team handles the repair and the paperwork. Start with what a Chicago violation notice says. And if the question is really about a permit on your specific job, the Department of Buildings has the last word. Confirm before work begins.

Common questions

This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.