Concrete Curing Time

In short: in mild weather you can usually walk on new concrete after 1 to 2 days, drive a car on it after about 7 days, and treat it as reaching its design strength at 28 days. Concrete keeps getting stronger as long as it stays damp and warm, so how you treat it in the first week matters more than the calendar.

Typical timeline (around 70°F / 21°C)

When	What is usually safe
First 24 hours	Keep off. Protect from rain, frost, kids and pets.
1 to 2 days	Light foot traffic. Remove side forms on slabs and footings.
3 days	Set deck posts on footings and do light framing (no heavy loads yet).
7 days	Cars on a driveway. Concrete is roughly 65 to 70% of its design strength.
28 days	Design strength. Heavy trucks, RVs and full loads. Concrete still gets slightly stronger after this.

Weather changes everything

• Cold: below about 50°F concrete gains strength much more slowly, and if fresh concrete freezes it can be permanently damaged. Use insulated blankets and add days to every step above.
• Hot, dry or windy: the surface dries too fast, causing cracks and a weak, dusty top layer. Keep it damp.

How to cure concrete properly

Curing means keeping the concrete moist and at a reasonable temperature so the cement keeps reacting. For about the first 7 days, do one of these:

1. Mist or sprinkle it with water several times a day and keep it damp.
2. Cover it with plastic sheeting or wet burlap, weighted at the edges.
3. Spray on a curing compound right after finishing (the easiest option for DIY).

Curing is not drying

A slab can be strong but still full of moisture. Before laying wood flooring, vinyl, carpet or epoxy on new concrete, the slab must dry enough to pass the flooring maker's moisture test. That often takes many weeks to months, much longer than the 28-day strength mark.

Engineer's note: the 28-day strength is what engineers design with, but it assumes the concrete was cured. Concrete left to dry out in the sun on day one can end up noticeably weaker at the surface for its whole life. For deck footings, pouring and then setting posts too early is rarely the problem; loading a beam full of joists before the footing has had a few days is. When in doubt, wait a week.

Common questions

How long before I can put a deck post on a new footing?

Setting the post base and post after 24 to 48 hours is common. Wait about 3 to 7 days before putting the full weight of beams, joists and decking on it.

Can I drive on concrete after 3 days?

Not recommended. Wait at least 7 days for cars, longer in cold weather, and 28 days for heavy vehicles.

Does rain ruin new concrete?

Heavy rain in the first few hours can wash out the surface finish. After the concrete has set (usually 4 to 8 hours), rain actually helps curing.

Planning a pour? Work out the amount with the concrete slab calculator or the concrete for post holes calculator.

Written and checked by: Engr. Abdul Latif, civil and structural engineer. Strength values are typical for ordinary Portland cement concrete; follow your mix supplier's guidance. For guidance only.