In a Las Vegas June the air pulls water out of fresh concrete faster than the curing reaction can use it. Starting early is not the crew avoiding the heat. It is the only way the slab reaches its strength.
Curing is a chemical reaction between cement and water, and it needs that water to continue. In the valley in summer you have high air temperature, very low humidity and often wind — the three conditions that drive evaporation — all at once.
The surface loses its water to the air before the reaction has finished with it. That leaves a top layer that never reached full strength, sitting on concrete that did. It looks identical and it wears away under traffic.
The visible version appears within hours, while the concrete is still soft: short roughly parallel cracks across the surface. The surface contracted as it lost water, and the slab had no strength yet to resist it.
On a plain slab it is cosmetic. On decorative work — stamped, stained, coloured — it ruins the appearance of the thing you actually bought, and it cannot be polished out.
October through April is straightforward in the valley and is when decorative work should be scheduled. June through September needs pre-dawn starts, and some jobs should simply not be attempted in the middle of the day.
This is different from a temperate climate where summer is the good season. In Las Vegas the summer is the constraint, and a contractor who schedules a large stamped patio for a July afternoon is either inexperienced or does not care how it turns out.
Pre-dawn placement so the finishing happens before the worst of the day. Cooling the subgrade and the forms with water before the truck arrives, so the slab is not losing heat into hot ground. Evaporation retarder on the surface during finishing. And then curing — keeping the slab wet or sealed for days, not hours.
And what should not happen: water added at the truck to keep the mix workable in the heat. It makes placing easier and lowers the final strength directly, and the temptation is highest on exactly the days when strength matters most.
If you are planning decorative concrete, book it for the cool half of the year and you remove an entire category of risk for free. If it has to happen in summer, expect an early start and do not treat that as an inconvenience — it is the crew doing the job properly.
A texture pressed into the surface while the slab is still plastic.
Yes, with pre-dawn placement, subgrade cooling, evaporation retarder and proper curing. Without those, high heat, low humidity and wind pull water from the surface faster than curing can use it.
October through April. Decorative work in particular should be scheduled then, because the finisher needs working time before the surface sets.
Usually plastic shrinkage cracking from a hot dry pour: the surface lost water and contracted before the slab had strength to resist. It appears within hours and is permanent.
Walkable in 24 to 48 hours, vehicles at seven days. Curing continues for 28 days, and keeping the slab wet through the first week matters more than anything after it.
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Photos of recent pours, before and after shots, and the jobs we are on this week.