Concrete questions, answered

Foot traffic after 24 to 48 hours. Passenger vehicles after seven days. Heavy vehicles, delivery trucks, dumpsters and RVs after 28 days. Concrete reaches around 70 percent of its design strength in the first week and the remainder over the following three, so those windows reflect real strength gain rather than caution.

Yes, somewhere — concrete shrinks as it cures and that movement has to go somewhere. The purpose of control joints is to decide where it happens. Correctly spaced and timely-cut joints mean the cracking occurs inside the joint where it is invisible and harmless. Cracking outside the joints usually points at joints cut too late, spaced too far apart, or a base problem.

Not exactly, and anyone promising an exact match is overselling. New concrete cures lighter and weathers over one to two years toward the surrounding slab. We can match finish direction and texture so the transition reads as intentional, and colour converges over time, but a new section will be visible initially.

Replacing an existing driveway in the same footprint on private property usually does not require one. Work in the public right-of-way — typically the apron between the sidewalk and the street — often does, and requirements differ between Charlotte, the surrounding towns and NCDOT-maintained roads. We establish which applies before we start.

Load capacity. Four inches is correct for passenger vehicles on a properly compacted base. Six inches with reinforcement is the right specification for RV and trailer pads, heavy vehicle parking, and garage bays with a lift. Uniformly upgrading an entire driveway to six inches is usually spending money in the wrong place — thickening the specific area that carries the load is better value.

Sealing helps, but not immediately. New concrete needs to cure before sealing, typically around 28 days. After that, resealing every two to three years reduces water penetration, which is the mechanism behind most freeze-thaw surface damage in this climate. Keeping control joints sealed matters more than sealing the surface — open joints let water straight into the base.

Often, and we will tell you when that is the better answer. Sound slabs with localised damage — a settled panel, crumbling edges, isolated cracks — are repair candidates, and slab lifting can bring a dropped section back to grade in a day. Widespread pattern cracking or repeated movement after correction indicates base failure, and repairs on a failing base do not last.

Efflorescence — mineral salts carried to the surface by moisture moving through the slab, left behind as the water evaporates. It is cosmetic rather than structural and it typically diminishes over the first year. Persistent heavy efflorescence suggests ongoing moisture movement through the slab, which is worth investigating.

Yes, with limits. Concrete needs to stay above freezing while it gains initial strength, so we monitor the forecast across the cure window rather than just the pour day. In cold conditions we adjust the mix, use blankets, and sometimes reschedule. We will not pour if the forecast puts the slab at risk — moving a date costs you a week, and a frozen slab costs the whole job.

Spalling, usually caused by water in the surface freezing, or by de-icing salt. It is common on slabs that were over-troweled or finished while bleed water was still present, both of which weaken the top layer. Surface spalling on a structurally sound slab can be resurfaced. Spalling combined with cracking and movement usually means replacement is the more sensible spend.

Some, and we would rather tell you that upfront. Machine access leaves tracks, and the area either side of a driveway takes traffic during tear-out and pour. We protect what can be protected and restore grade where we have disturbed it. Full landscaping restoration is not included by default, but we will tell you at quoting stage what we expect to disturb.

We stand behind our workmanship. What no honest contractor can guarantee is that concrete will not crack, because it will — that is a property of the material. What we are accountable for is that the base is built as specified, the slab is the stated thickness, joints are cut correctly, and the work is done to the written scope.