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Almost every slab cracks. Concrete shrinks as it cures, the ground under it shifts, and roots and water do the rest. Most cracks are not an emergency. But a crack is an open door for water, and in a place that gets as much rain as Fort Lauderdale, water under a slab leads to bigger problems.
Concrete crack repair in Fort Lauderdale
We repair cracks in driveways, garage floors, patios, lanais, walkways, carports and steps. Before we fill anything, we work out what kind of crack it is. A crack that formed in the first year and has not moved since is handled very differently from one that opens a little wider every rainy season.
Why does concrete crack?
* Shrinkage. Concrete loses water as it cures and gets slightly smaller. Control joints are meant to guide these cracks into straight lines. When joints are missing or too far apart, the slab makes its own. * Settlement. Sandy fill can settle or wash out, leaving part of the slab unsupported. * Roots. Tree roots lift one side of a slab and snap it. * Loads. Trucks, dumpsters and boat trailers put more weight on a driveway than it was built for. * Rusting steel. Near the coast, salt reaches the reinforcing steel. Rust expands and cracks the concrete from inside. That is the start of spalling.
Which cracks should I worry about?
Use these as a guide:
- Hairline cracks that have looked the same for years are mostly cosmetic. Sealing them is cheap protection.
- Cracks wider than about a quarter inch let in a lot of water and should be repaired.
- Cracks where one side is higher than the other mean the slab has moved. They are also a trip hazard.
- Cracks that are getting longer or wider mean something is still going on underneath.
- Cracks with rust stains point to steel corroding inside the concrete.
How are concrete cracks repaired?
1. We check the crack for movement, depth and height difference. 2. We open the crack into a clean channel with a grinder. This is called routing. It gives the repair material room to grip. 3. We vacuum out dust and loose grit. 4. For cracks that move, we use a flexible sealant that stretches. For cracks that are stable, we can use a rigid repair material such as an epoxy or a polymer mortar. 5. We tool the repair flush with the surface.
Pouring a liquid filler into a dirty crack is the quick version, and it usually pops out within a season. Routing and cleaning are what make a repair hold.
Will the repaired crack still show?
Yes, by itself it will. A filled crack looks like a neat line of a slightly different color. For many people that is fine on a driveway or a side walk. If you want the cracks gone from view, the next step is concrete resurfacing or, in a garage, a garage floor coating. Both go over the repaired cracks and give one even surface.
When is a crack more than a crack?
Sometimes the crack is a symptom. If a slab has dropped, rocks under weight or has broken into several pieces, filling the cracks will not fix it. That section needs to be replaced on a properly compacted base. The same is true when large roots are under the slab. We will show you what we see and explain the choices.
Why crack repair matters more in South Florida
We get around five feet of rain a year, and much of it falls in hard summer bursts. Water that runs into a crack washes fine sand out from under the slab, a little at a time. That is how a thin crack becomes a sunken corner. Near the ocean and the Intracoastal, the same water carries salt down to the steel. Closing cracks early is cheap. Replacing a section later is not.
Cracks in garage floors and carports
Garage and carport slabs crack in a few typical places: across the middle, out from the corners of the door opening, and along the line where the slab meets the driveway. Most of these are shrinkage cracks that stopped moving long ago. We route them, fill them with a rigid repair material and grind the repair flat. If you plan to coat the floor, this is done as part of the prep, and the cracks disappear under the coating.
Can I just caulk a crack myself?
For a thin crack on a side walk, a tube of concrete crack sealant from the store is better than nothing. The usual problems are that the crack was not cleaned, the material was smeared over the top and not pushed into the crack, or the wrong product was used. On a driveway that carries cars, a store caulk rarely lasts. If the crack is wide, uneven or growing, have it looked at before spending money on it.
What about cracks along control joints?
Those are good news. A control joint is a groove cut or tooled into the slab so that when it cracks, it cracks there, in a straight line. A crack at the bottom of a joint means the joint did its job. These joints should still be sealed so water does not run down through them and wash out the base.
What does crack repair cost?
It is priced mostly by the length and width of the cracks and how much prep they need. A few cracks on a driveway is a small job. See our concrete repair cost guide for the other factors. Estimates are free and in writing.
For cracks on a driveway, also see concrete driveway repair. After the repair, concrete sealing helps keep water out of the rest of the slab.
