Are you planning to pour a concrete slab, but don’t know how long you should wait before you can remove the forms and start building on top of it?
Search no further, I’ve gathered some common questions that will help to answer how long does concrete takes to dry. Depending on different conditions that can happen.
How long should concrete cure before removing forms
Concrete formwork removal time depends on the thickness of the slab. Driveways, sidewalks, and building slabs are all made with different thicknesses depending on the load they have to handle.
4 inch concrete curing time is around 28 days. For the concrete to be fully dry, it will take months (around a month per inch). That doesn’t mean you have to keep the forms in place for 4 weeks.
Notice that curing and drying are 2 different things. When concrete cures, water reacts with cement and hardens over time. There can still be moisture in the concrete after that.
Now, to get to the forms. When you can remove the forms depends on what kind of forms they are. For slab forms and support pillar forms, the times will be different as it will be for different types of cement used.
The concrete needs to reach a proper strength before the forms are removed. How fast that will be achieved depends on the quality of cement and concrete and is it rapid cement or Portland cement.
Slabs might need 3-4 days before the forms can be removed. If the slab has props under them, it will depend on the slab size when those can be removed, This can take weeks.
How long to leave forms on concrete walls then? Walls are more simple as the forms can be removed in day or two. Most recommend to keep them for 2 days.
How long does concrete take to dry before rain
You can probably guess that fresh concrete that is just poured and rain are not a good combination. It will mix the water-cement ratio on the surface and ruin it. If the surface is not finished yet and the rain won’t last that long, it might be possible to finish it as the rain stops.
Now, if it rains for days you’re better off watching weather reports and pouring when it doesn’t rain. We all know that it can rain despite what the weather cast says, but generally, it’s a good idea.
How to protect concrete from rain depends on the size of it, what can be used to cover it, and the time that has passed since the pour. Fresh concrete can be protected with plastic or something else waterproof over it, if enough time has passed and you can walk on it already, other solutions can work too.
If there is water on the fresh concrete surface, you can sweep it off so it doesn’t affect the curing process.
After half a day has passed, you will be a bit more safe from the weather and little rain won’t ruin the surface. I’d still cover it thought.
How soon should I water concrete after pouring
Now you have just been warned of water on top of concrete after pouring, but what about wet curing? It is recommended to water the fresh concrete with a hose up to 10 times a day for a week so how soon should I water concrete after pouring?
The answer is between the first 6 and 24 hours. It’s hard to say exact time, but depending on weather hit between that time.
How long should fresh concrete be kept wet
After you have started wet curing, keep it moist every few hours. The first week is where most of the gains are made, but wet curing beyond that will make the concrete even harder.
So when to start water curing concrete has a good time window to start. If you can’t make it up to 10 times a day, get something to cover the concrete on hot days. Something that will stop the water evaporation.
When do you wet concrete after pouring? You can start from the morning and divide the time until evening. If you can do it every 2 hours that would be great.
How long does concrete take to dry in cold weather
If you live in colder climates, you might be thinking is it OK to pour concrete in cold weather. I have written a guide on cold weather concreting as stated at the beginning, but we can briefly go through it.
You need to keep the concrete warm so you should choose a time when the temperature isn’t extremely cold. The ice and snow need to be removed from the forms before the pour and then the concrete should be kept warm while it cures.
What temperature is too cold to pour concrete? Professionals say 40°– 60°F is the best, when the temperature dips below 40°F the chemical reactions will be affected. All I can say is that it is too cold when you can’t keep that bottom line.
If you can keep the space above 40°F, it doesn’t matter how cold it is outside. If you have bad insulation, even above freezing point can be too bad. If you have good insulation and heating, you can do it way below the freezing point.
Now you must be thinking how long does concrete need to cure before freezing? The concrete will produce some heat while it cures and it shouldn’t freeze during the first 24 hours no matter what. After that, the heating can continue up to 20 days or even more.
It really depends on the project. There is also a problem with the moisture during winter as there isn’t much in the air and the heaters will eat some of that so the whole process is rather special.
How long does concrete take to dry to walk on
How long should concrete cure before putting weight on it? I’d say at least 24 hours and you should walk carefully. If you twist your feet on it, it might break the surface finish. So if you’re not in a hurry, let it be for a little longer time.
If you’re in a hurry, you can use something on top of the concrete so it will be safer to walk on and your boots won’t make damage.
How long does concrete take to dry indoors
This is left as last, but it is still asked sometimes. Indoors, outdoors doesn’t make any difference. It will still take up to 28 days to cure inside. The traffic can be started carefully after 24 hours, but the floor might need to be protected.
You might be in hurry to get all your installing going so how long should I wait to put furniture on new concrete? Now we’re indoors so you might not be wet curing the floors.
If you are, wait until it’s done and the concrete gets to dry a little bit. Moisture escaping from the floor does no good to metal and wood.
There is also the question of what are you doing to the floor. I wouldn’t install any flooring until the floor has cured for 28 days.
For things like kitchen cabinets and other things like that, I would give the floor some time. If you intend to do flooring after 28 days, install them a little bit before that or on top of that.
A simple how long does concrete take to dry question took us quite far. It all depends on conditions, but not that much. The key points are you can walk on it after 24 hours, should protect it from rain well to that point and if wet curing, water it for a week.