As long as the concrete mix has been made correctly, in most cases, concrete will be dry enough to walk on within 24 to 48 hours. However, after this short period, the concrete is still drying out and getting stronger (curing) each day but it’ll eventually reach its full strength after 25 to 28 days of drying.
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Concrete Drying vs Curing
Although similar, concrete drying and curing are different processes. This is because curing is the process of the concrete hardening whereas drying is where the water inside evaporates through the surface.
Curing is an important process and it’s mostly dictated by the moisture content of the concrete. For example, if the concrete was made correctly, it’ll continue to gain strength for as long as there is moisture/hydration in the mix. However, if the mix was made with too much or too little water, it can lead to weaker concrete.
Factors That Affect The Drying Of Concrete
As mentioned above, the moisture content of the mix plays a big role in terms of how long concrete takes to dry. Although a mix with less water will dry quickly, it would also cure quickly, which means it would be weaker. On the other hand, a concrete mix that’s too wet will take much longer to dry and it may also flake on the top layer once it has dried.
The temperature is also a major factor of the speed to which concrete dries and as you can imagine, the hotter it is, the faster concrete dries. However, this doesn’t mean that you should increase the heat too much in the room because it’ll cause the concrete to dry too quickly and eventually cause cracks to appear.
Another major factor is of course the concrete mix because certain mixtures have faster curing and drying times. You can even add an accelerant into the mix to speed things up if required.
How To Tell If Concrete Is Dry?
Without testing the concrete using a specialist moisture meter, you wouldn’t be able to confidently say if its dry by just looking at the surface. However, as stated above, as long as the concrete was mixed correctly, it should be safe to walk on within 24 to 48 hours. It will then be fully dried out and at its full strength by 25 to 28 days of it being laid.
Although the timescales are standard across the industry, you should still use your common sense. For example, if the concrete still looks wet, don’t walk on it or begin laying slabs, tiles or any other type of flooring.
Below is an example of what concrete looks like after drying for 48 hours from a recent DIY project. As you can see, the concrete is much lighter in colour due to the water evaporating through the surface. However, although it looks much dryer, the centre of the concrete will still be moist and need a few more days to fully dry out.
How To Speed Up The Drying Process of Concrete
If you need to speed up the time it takes for concrete to dry due to a time constraint, you can use some of our tips below:
- Ensure that you mix up the concrete correctly
- Use an accelerant in the mix
- Remove moisture in the air by using a dehumidifier
- Avoid covering or sealing the surface
- Use a concrete blanket (if drying in cold weather)
- Turn on the central heating to a low temperature
Although waiting for concrete to dry can delay certain DIY projects, it’s crucial that you give it enough time. By being to eager, you may weaken the concrete and also cause cracking to occur. If you are under a certain time constraint, the above tips will certainly help speed the time it takes for concrete to dry. However, if you need further information or help, feel free to get in touch and we will try to provide our assistance where possible.