FAQ · Concrete
Concrete Questions, Answered
Direct answers on concrete strength, curing versus drying, control joints, reinforcement, overlays and color, for driveways and patios in Greater Orlando and Sarasota-Manatee, as of October 2026. For a specific driveway, patio or pool deck project, the service pages linked throughout go further than this FAQ does.
By the Opera Concrete & Pavers estimating team · Updated October 1, 2026
Strength and reinforcement
Florida's residential code sets a floor, not a target. FBC Residential R506.1 requires any slab on the ground to be at least 3½ inches thick, and Table R402.2 ties required strength to a weathering-exposure class rather than one number for every pour (FBC Residential Ch. 5; FBC Residential Ch. 4). Most driveways and patios in Greater Orlando and Sarasota-Manatee are built heavier than either floor: our driveway page and our patio page cover the specific thickness and mix for each project type. Reinforcement, fiber, wire mesh or rebar, is a separate decision from strength, and the question below covers what each one actually does.
| Term | What it means | Typical Florida driveway or patio |
|---|---|---|
| Weathering-exposure class | Sets the strength floor under FBC Table R402.2, not one number statewide | Most residential flatwork is poured well above the floor, at 3,000-4,000 psi |
| Fiber mesh | Synthetic fibers mixed through the whole batch, not laid in sheets | Common standard reinforcement for a driveway or patio |
| Wire mesh | A welded steel grid, pulled up into the slab as the pour proceeds | Specified where a heavier load is expected |
| Rebar | Steel bar, used where a slab needs more support than mesh alone gives | Thickened edges, footings and heavier pads |
Curing, joints and cracking
A poured slab goes through two different processes that get confused for one another, and it loses strength or finish quality when either one gets rushed. NRMCA's own guidance is to keep the surface moist for at least 3 days after finishing, not the 7-day figure some older references repeat (NRMCA CIP 12; NRMCA CIP 5). Control joints are cut while that moist-curing clock is already running, within hours of finishing, not after the slab has dried out. How concrete cures in Florida heat and humidity and which cracks are normal in a new driveway go further than the two questions below.
Overlays and color
Existing concrete factors into two common questions: whether new concrete can go over it, and why a fresh pour doesn't always look uniform right away. Both come down to bond and curing conditions rather than a flaw in the mix itself. Our repair and resurfacing page covers overlay thickness and when a full tear-out is the better call instead of a bonded layer on top.
Concrete terms homeowners ask about
A handful of words get used loosely around a job site, and one mix-up comes up often enough to answer directly below. The concrete services hub lists every concrete project we build, from driveways to slabs, in plain terms rather than industry shorthand.
Concrete questions homeowners ask most
What strength (PSI) concrete is used for driveways and patios?
3,000 to 4,000 psi is standard for residential driveways and patios in both service areas, above Florida's code floor of 2,500 to 3,500 psi set by weathering-exposure class (FBC Residential Table R402.2). Some right-of-way specs set their own minimum regardless of the rest of the slab: Orlando's engineering standards manual requires the apron section specifically to be at least 3,000 psi and 6 inches thick (City of Orlando Engineering Standards Manual).
What is the difference between concrete curing and drying?
Drying is water leaving the slab; curing is the chemical reaction, hydration, that gives concrete its strength, and that reaction needs moisture to keep going rather than losing it fast. A slab that dries out too quickly, which a hot, dry, windy Florida afternoon does easily, cures unevenly and can craze or crack at the surface even though it looks dry and finished on top.
Why do contractors cut lines (joints) into concrete?
Concrete shrinks as it gains strength and will crack somewhere regardless, so a control joint gives it a planned, straight line to crack along instead of a random one across the middle of the slab. Industry spacing guidance multiplies slab thickness by 24 to 36; on a typical 4-inch driveway or patio that lands joints about every 8 to 12 feet, cut to roughly a quarter of the slab's depth within hours of finishing (NRMCA CIP 6).
Is fiber mesh as good as rebar or wire mesh?
They solve different problems, so it isn't really a fair swap. NRMCA's own guidance, and the same logic applies to rebar and fiber, is that wire mesh doesn't keep a crack from forming in the first place; it only keeps a crack from opening wider once one does. What actually decides where a slab cracks is correct, well-spaced control joints, not which reinforcement sits inside the concrete.
Can new concrete be poured over old concrete?
Sometimes, as a thin bonded overlay, but it depends on the old slab's condition more than on preference. The existing surface has to be structurally sound, profiled or roughened for bond, and free of oil, sealer or coatings; a cracked or settling slab underneath will usually telegraph the same crack through a new overlay within a season or two. Our repair and resurfacing page covers when an overlay works and when it doesn't.
Why does new concrete look blotchy or uneven in color?
Almost always from uneven curing, not a bad batch. Spots that dry or cure faster, near an edge, under direct sun, or where curing compound went on thin, lighten or darken differently than the rest of the slab while it's fresh, and most of that variation fades as the concrete finishes curing over the following weeks. A color that's still sharply blotchy past a month is worth a call.
Is concrete the same as cement?
No, though the two words get used interchangeably around a job site, including by us sometimes. Cement is the fine gray powder, a binder, mixed with water, sand and crushed stone to make concrete; concrete is the finished, poured material. A driveway, patio or slab is concrete, not cement, even though plenty of homeowners ask for a cement driveway and mean the same thing.