How to repair cracks in concrete by width, and get oil stains out first

Which concrete crack filler to use: read the crack first

The filler follows from two things, the crack's width and whether it moves. Measure the width with a drill bit: a 1/8 in. bit that drops in tells you more than a guess. Then sort each crack into one of these rows. The product follows from the row.

The two injection rows are easy to confuse. Sika's epoxy kit is for static cracks only, not over 1/4 in., and not under hydrostatic pressure, meaning not actively leaking. Its polyurethane grout, SikaFix HH LV, is made for exactly that case: it reacts with water, expands up to 30 times and stays flexible in a moving crack. Epoxy in a leaking crack is money poured into a hole.

NRMCA also names two kinds of cracking that are not cosmetic: D-cracks, which start at joints in slabs with freeze-thaw-sensitive aggregate, and cracking from alkali-aggregate reaction. Both keep getting worse, and no filler fixes the concrete around them.

Materials for one driveway crack repair, with quantities

The case: the 20 × 24 ft driveway from the concrete slab cost guide, now a few winters old. It has 30 ft of random cracks about 1/4 in. wide, 44 ft of control joints with failed sealant, opened to 1/2 in., a chipped spot 1 × 1.5 ft and about 1/2 in. deep, and a 2 × 3 ft oil stain where the car parks.

The pail math: Quikrete rates 10 lb of Vinyl Concrete Patcher at 8.5 sq ft at 1/8 in., which is 0.0885 cu ft. The spall is 1.5 × 1 ft × 1/2 in., or 0.0625 cu ft, so one pail with a little left over. The joint math checks too: 44 ft × 1/2 in. × 1/4 in. is 66 cu in., and a 10 oz tube holds about 18, so 3.7 tubes. Buy 4. For a fine horizontal crack you would rather pour than gun, Quikrete Concrete Crack Seal was $14.99 a quart, rated for cracks up to 1/2 in. The concrete calculator runs the same volume math for bigger patches.

Prices are one retailer's online prices on one day, before tax. Expect some drift at your store.

Tools you need to repair concrete cracks

Must have: a wire brush, a cold chisel and hammer, a shop vacuum, a caulking gun, a putty knife or margin trowel, a small steel trowel, a stiff nylon scrub brush, a bucket, nitrile gloves and eye protection. Quikrete's epoxy sheet calls for an N95 mask during prep that makes dust.

Worth renting or borrowing: an angle grinder with a diamond blade if you are opening many feet of hairline crack or squaring the edges of a patch. A pressure washer speeds the rinse after the degreaser. A crack-chasing router is a contractor's tool; on 30 ft of crack the chisel does the job.

How to repair cracks in concrete, step by step

1. 1. Get the oil out first

   Every filler sheet here wants the surface free of oil and grease, so the stain comes before the crack. If the spill is fresh, cover it with an absorbent at once; the Canadian building digest on concrete stains names hydrated lime, fuller's earth or whiting. For a set stain, scrub with TSP solution (Savogran: 1/2 cup in 2 gallons of hot water) or Quikrete's cleaner at 1:1 or full strength for heavy soil, rinse, and let the slab dry. Then pour the poultice on the dry surface. Pour-N-Restore dries to a powder in 5 to 8 hours above 60°F; Prosoco's version says 5 to 8 hours or overnight, and not to pre-wet. Sweep, rinse, repeat if the stain wicks back.

   Check: the powder is fully dry and cracked across its surface before you sweep, and the area is dry to the touch before any filler goes near it.

2. 2. Clean and open the cracks

   Chip out loose edges with the chisel, wire-brush, and vacuum. Quikrete's Concrete Repair sheet says to open any crack narrower than 1/8 in. to at least that width, or the filler just bridges the top. Cut out the old joint sealant completely; the self-leveling sealant must not go over silicones or other sealants.

   Check: a 1/8 in. drill bit drops into every crack you plan to fill, and a fingertip run down the crack comes out clean.

3. 3. Set backer rod in the joints

   The sealant sheet wants a working depth between 1/4 and 1/2 in. and a width-to-depth ratio of 2 to 1, so a 1/2 in. joint gets 1/4 in. of sealant. Press the foam rod down with a blunt stick until it sits 1/4 in. below the surface. It also keeps the sealant from bonding to the bottom of the joint, which lets it stretch.

   Check: a 1/4 in. mark on the stick touches the surface at every point along the rod.

4. 4. Fill the random cracks

   Cut the tube tip to a 1/4 to 3/8 in. hole, push the bead deep into the crack and tool it flush. No more than 3/8 in. per application; on deep horizontal cracks, fill part way with sand first. Air and slab above 40°F, and no rain for 12 hours.

   Check: the bead sits flush or a hair proud with no voids along the edges; nothing is forecast for 12 hours.

5. 5. Seal the control joints

   Gun the self-leveling sealant with the nozzle near the bottom of the joint so no air gets trapped, and let it flow level. Apply between 40°F and 95°F, and check the slab temperature in direct sun. It is tack-free in about 100 minutes at 77°F and takes traffic after 3 days.

   Check: the sealant sits just below the slab surface, level along the joint, with no pinholes after 30 minutes.

6. 6. Patch the chipped spot

   Pry out anything loose, wire-brush, clean with the concrete cleaner and rinse. Mix about 10 fl oz of water per 5 lb of Vinyl Concrete Patcher, dampen the spot, remove standing water, and force the mix in with heavy trowel pressure. Overfill slightly and feather to the surrounding surface; it goes as thin as 1/16 in. In hot, dry or windy weather keep it covered with plastic for 24 hours.

   Check: no hollow sound when you tap the patch the next day; foot traffic after 1 day, wheels after 3.

7. 7. Keep cars off, then look again in spring

   Three days is the longest wait on this list, set by the joint sealant. Full cure is 3 to 7 days, longer when it is cool and dry. After the first winter, walk the slab: a filled crack that has reopened in the same line was moving, and belongs in the flexible-sealant row next time.

   Check: day 4 or later before the car goes back on it.

How to get oil stains out of concrete: which method, how long

Coverage decides the bill. Pour-N-Restore rates a 32 oz bottle at 6 sq ft; Prosoco rates a quart at 2 to 3 sq ft. Old stains often need two rounds because oil deeper in the slab wicks up after the first. The 1972 digest's own poultice used benzol, which is benzene; the commercial poultices above do the same job without it. On a sealed driveway, test a spot first: Pour-N-Restore warns it can leave a white or shiny residue in some sealers.

Mistakes that cost money

Should you repair concrete cracks yourself or hire a cement mason?

On a driveway like this one, do it yourself: $129.48 of material against about $466.28 hired. The BLS May 2025 mean wage for cement masons and concrete finishers is $28.87 an hour. BLS employer-cost data for construction in June 2026 put total compensation at $51.96 against $36.13 in wages, a factor of 1.4381, so a mason costs an employer $41.52 an hour. With a 30% markup for overhead and profit (my assumption), the hour bills at $53.97.

Doing it yourself saves $336.80, or $56.13 for each of the six hours. That is well above the mason's own wage, and the tools cost little, so this is a job worth doing yourself. Two exceptions change the math. A contractor may bill a minimum trip, which makes a small job cost more than the hours say. And a structural wall crack moves the job out of this table altogether, into an engineer's report and a repair contractor's bid.

If the slab is too far gone to patch, the slab cost guide prices a tear-out and a new pour, and shows one replaced driveway panel at about $1,490 to $1,970.