How Long Does It Take for Concrete to Dry? (2024 Guide)

Concrete has the power to transform your property, creating the driveways, patios, and walkways you’ve always wanted. But you need to let it properly dry and cure before moving on to the next steps in your project, or the concrete will crack and crumble apart.

Whenever I pour concrete, I give it 48 hours before I consider it ready to walk on – and as long as 28 days for a full cure. However, keep in mind that many factors impact drying times, such as the water-cement ratio and the temperature outside. 

In this guide, we’ll explore all those factors together so you can get great results when working with concrete. 

How Long Does Concrete Take to Dry?

In average conditions, concrete takes 24 to 48 hours to harden enough to walk on, one week to support the weight of vehicles, and 28 days to fully cure. This assumes that the concrete has a water-cement ratio of 0.5 and it’s a nice 70°F day with 50% relative humidity. If you change any of those factors, your concrete could dry faster or slower than that. 

Wondering how that works? Let’s look at how each factor impacts drying times and how to adjust them. 

Type and Size of Concrete

Concrete is a blend of aggregate, cement, and additives, also known as admixtures. Drying times vary depending on the cement type, aggregate size, and admixtures used in your mix design. 

Quick-setting concrete has additives that speed up drying times, allowing you to walk on its surface in just two hours. Standard and high-performance concrete takes up to 48 hours to dry. 

Mixtures with large aggregate pieces can extend drying times. All ready-mix concrete at the hardware store has a fine aggregate made up of sand and crushed stone. The smaller particles have a uniform surface area that allows moisture to escape quickly for the fastest drying times. 

You must match your mix to your application to get the best results. Quick-setting mixtures offer instant gratification, but their strength may not hold up to your intended uses. 

Water-Cement Ratio

The water-cement ratio affects workability, strength, and drying times. The more water you add, the longer it’ll take to fully dry and cure. The extra moisture makes it easy to pour the mixture into forms and smooth it all out. 

Less water creates a higher-strength mixture but is much harder to work with. The concrete may not flow into all the nooks and crannies, creating gaps and weak points. The finished surface may also erode much faster. 

Much like pancakes, you can adjust the ratio by adding more water or cement. But you cannot go back after you’ve started your project, so create a trial batch before beginning. Perform a slump test to ensure it’s workable and will dry to your desired strength. 

Ambient Temperature and Humidity

Concrete dries best when it’s between 50°F and 80°F. The ideal relative humidity range is between 40% and 60%. Working when the weather is outside those ranges will only result in heartbreak, so wait it out if possible. 

If you go ahead when it’s hot outside, the concrete will rapidly dry and likely crack in the near future. When it’s too cold, you might feel like the mixture will never dry.

Relative humidity has similar effects. If it’s too high, the extra moisture in the air slows the drying process. Lower humidity levels speed up drying and greatly reduce the concrete strength. 

We’ll go over the curing methods that help with humidity in a moment. As for temperature, never pour concrete when it’s cold out. 

If it’s too warm, mitigate the heat by:

• Keeping the bags of concrete cool until you need them
• Using cold water to mix each batch of concrete 
• Lightly spraying the ground with water before you pour 

Working bright and early in the morning can help, too. Hiring a contractor is also an option if you cannot work fast enough to beat the heat. 

Curing Methods

The curing methods you use will impact the concrete’s drying times and strength. The plans typically involve adjusting the temperature and humidity to maintain the proper evaporation rates. 

This is important because of the chemical reactions that occur within the concrete as it cures. As soon as you add water to the mix, a chemical reaction called hydration begins and gradually builds its durable crystal structure. Once the water fully evaporates, the reaction stops, potentially keeping it from reaching full strength if it happens too quickly.

Curing methods used to keep the water evaporating at the correct rate include: 

• Ponding
• Sprinkling 
• Wet concrete coverings 
• Plastic sheeting 
• Curing blankets or membranes
• Curing with radiant heating systems
• High-pressure steam curing
• Sealing compounds 
• Water misting 

You can calculate the evaporation rate using the Menzel/NRMCA nomograph, but it is a highly involved process. Knowing the proper curing method to use can be tricky, too. So, if you need a high-strength finish, it’s best to work with a contractor to get the curing right. 

What is Concrete Drying Time?

Concrete drying time is how long it takes for the wet mixture to set and harden enough to walk or drive on. The curing time is how long it takes for the total amount of water in the mix to fully evaporate. Drying happens in 24 to 48 hours, while the curing process takes about a month. 

What’s the Difference Between Concrete Curing Time and Drying Time?

Drying time reflects how long the concrete takes to set up and harden. Curing occurs once all the excess water has evaporated, halting the chemical reaction. Both drying and curing affect the quality and performance of concrete. So trust me when I say that you cannot mix them up or skip the best practices for each one. 

How Do You Measure Concrete Drying Time?

Since so many variables exist, it’s hard to predict how long it will take for your concrete to dry. You can measure if it’s dry, however, by using any of the following methods. 

Moisture Meters 

A moisture meter is a handheld measurement device that makes it easy to take a reading. The device returns a moisture percentage that lets you know if the concrete has fully dried. 

For most moisture meters, you will need to follow these steps: 

1. Turn the unit on and find a shady area to take a reading.
2. Press the unit against the concrete until all the pins compress.
3. Hit the button to freeze the reading and record the percentage. 
4. Repeat in three to four more areas to get an accurate reading.

Use the lowest percentage as your baseline reading. The concrete is dry once it has a 3.5% to 4.5% moisture content. 

To get accurate readings, avoid measuring the center of the slab or within a few feet of nearby walls. Don’t take the readings in bright sunlight either because that can also throw off the meter. 

Calcium Chloride Tests

A calcium chloride test tells you the moisture vapor emission rate of the concrete. Since it provides quantifiable results, it’s the industry standard test. 

To perform this test, you will need a calcium chloride test kit, which comes with a calcium chloride disc and a plastic dome. You will also need a small postal scale and a utility knife. 

Once you have those items, follow these steps:

1. Mark off a 20” by 20” area and sweep off any debris.
2. Put the calcium chloride disc on the scale and record the dry reading, which should be around 30 grams. 
3. Remove the black tape from the disc and place it diagonally on the inside surface of the top of the dome. Remove the lid on the disc and set it to the side. 
4. Place the calcium chloride disc in the center of the area you marked off, being careful not to spill its contents.
5. Peel the protective plastic off the adhesive strips on the dome and press it firmly over the disc to seal the edges.
6. Let the dish and dome sit in place for about 72 hours.
7. With your utility knife, cut an access hole in the top of the dome to remove the disc without disturbing its contents. Don’t cut through the black tape. 
8. Remove the disc, reaffix the lid and tape, and place it on the scale. 
9. Record the new reading in grams and input the figure in the calculator provided by the test manufacturer. Or use this moisture calculator site instead. 
10. Repeat for every 1,000-square-foot area. 

The calculator will tell you how many pounds of moisture the concrete emits from 1,000 square feet every 24 hours. If your moisture levels are less than five pounds per 1,000 square feet, your concrete is dry and ready for coatings. 

Relative Humidity Tests 

Relative humidity tests allow you to measure the moisture level in the middle of the slab. You’ll need special tools and have to drill a hole in the concrete. If you’re not comfortable with that or simply don’t have the tools, leave this test to the professionals. 

Whether performed by you or a professional, the steps for this test are: 

1. Put on protective gloves, goggles, and a dust mask.
2. Drill about 40% of the way through the slab. If your concrete is 4” thick, drill down 1.5”. Vacuum up the dust.
3. Insert a plastic sleeve into the hole by gently tapping it with a rubber mallet, and then put the cap on.
4. Let the sleeve sit in place for 72 hours, allowing the concrete to cool down and return to its normal moisture levels. 
5. Remove the cap on the sleeve, insert the in situ probe in the hole, and look at the reading on the screen. Repeat the test three times to get the highest reading. 

Anything below 50% is a passing score. You must patch the hole with fast-setting mortar and let it cure before applying your coating. 

5 Tips to Speed Up Concrete Drying Time

If you want to speed up the drying time of your concrete, there are a few ways to do that, such as: 

1. Mix your concrete with warm water instead of cold. 
2. Select a quick-set concrete mix instead of standard or high-performance formulas.
3. Use a lower water-cement ratio or put a water-reducing admixture in your mix.
4. Install a vapor barrier in the work area before pouring to minimize moisture transfer.
5. Set up a fan or radiant heater to reduce humidity and speed up the evaporation rate. 

Always avoid coating, painting, or sealing the concrete before it’s fully dry. Otherwise, it’ll trap moisture and extend the drying times considerably. 

Learn More About Concrete Finishes

So, how long does concrete take to dry completely?

This can be a difficult question to answer without knowing what factors may impact your project. Everything from the type of concrete to the water-cement ratio affects drying times. 

In average conditions, your concrete will dry enough to walk on in 24 to 48 hours and drive on one week later. In about 28 days, consider the concrete slab fully cured and apply any coatings you’d like. If you want to be 100% sure it’s ready, complete a moisture test to confirm it’s cured.

If you keep the guidelines in mind and follow the best practices, you can get optimal results from your concrete project. But it’s never a bad idea to hire a concrete contractor if you’re ever feeling like you’re in over your head.