That smooth, newly poured patio looks so inviting doesn’t it? You just can’t wait to get started and begin laying out all your furniture can you? But you must wait, and you must be patient – because putting things on your wet concrete too soon will undo all your hard work.
When you’re laying a new concrete patio, you have to wait at least 7 to 10 days for it to cure before putting your patio furniture on it. You can walk on a newly poured patio after 2 days and it will be fully cured at 28 days.
Let’s dive down into this subject in more detail, and discover more about when concrete is ready for your outdoor furniture, and how to work with concrete when pouring a new patio…
How Long Before You Can Put Furniture On New Concrete?
Yes, we know you are anxious to start relaxing on your brand-new concrete patio. But you’ll just have to wait – experts say you can walk on a poured patio within 24 hours but recommend 2 days. They say to wait 7 to 10 days before adding patio furniture. At 28 days, your patio will be fully cured.
A cement patio will last for years – decades even, with little to no maintenance. But when it’s first poured, a cement patio is a little needy. Curing is the action taken to maintain moisture and temperature in a newly poured patio. Here’s the American Cement Institute’s Guide on curing.
Water plus concrete causes a chemical reaction that forms crystals of hydration. The crystals grow to form rock-hard bonds between the grains of sand in the concrete mix.
To keep the chemical reaction – the hardening – going, your patio needs to be watered often. If there’s no water, then there’s no hardening. The cement also needs to be pretty warm.
The chemical reaction that hardens concrete stops below 45° F. If you have a sudden cold front come through, you may need to warm your new patio so it can keep hardening.
Newly poured cement needs a lot of water to prevent weakening and cracking. You will have to apply water no matter what climate you live in. But if you live in a warm sunny climate, you will need to water it up to 10 times a day for at least the first week, ideally for the first month. Keeping it wet during the curing period will improve its strength and durability.
Experts say that cement will cure to 70% of its strength in a week. So does cement stop hardening in 28 days? Answer – nope. Cement never stops hardening. It just does so very, very slowly.
Here’s an entertaining video from a cement nerd on concrete curing.
When Should I Start Watering My Concrete?
Experts say to begin watering in the morning hours and not in the heat of the day. Pouring water on an already hot patio can shock the concrete (aka surface crazing). Begin your watering the morning after the pour and continue 5 to 10 times a day for at least a week.
The goal is to keep your brand-new patio saturated for the first week, and some experts say for the first 28 days. SATURATED! Like 5 or 10 times a day.
Saturating newly poured concrete is called moist curing. Moist cured concrete can be up to 50% stronger than a patio poured and then left without watering.
Is it OK if it rains After Pouring Concrete?
Your best bet is to plan your pour for good weather. If the forecast is iffy, consider having some heavy plastic sheeting on hand. If it starts raining unexpectedly in the first 2 to 4 hours after pouring, you should try to protect the surface. It’s still too soft.
Drape some heavy plastic over it to protect it. If rain pools on your soft concrete, you should never mix it in. Mixing in water will skew the water/concrete balance and may weaken it.
First, set up a waterproof cover. Then, try to get rid of the rainwater with a mop or suck it up with a wet vac. If the cement is hard enough, you can pull some garden hose over the top to sweep away the water.
If your patio is over 4 hours old, then the rain should be OK.
Should You Cover Curing Concrete With Plastic?
If you can’t water down your patio 5 to 10 times a day, then covering it with plastic or burlap (aka a curing blanket) is a good Plan B. You’ll still need to water down your patio, but only once or twice daily.
Rapid moisture loss is your enemy in concrete curing. If you live in a sunny climate and can’t be home all day (for a week), then covering it will help. Covering a newly poured patio with plastic also helps reinforce the “no walking on it” ban and it keeps debris and dirt from the surface.
You can use a waterproof blanket, like heavy plastic, or a moisture-retaining blanket, like burlap (aka a wet cure).
Invest in a heavy (4mm or heavier) plastic sheeting. First soak your patio. Then, lay out the sheeting over the slab. Weight down as many of the edges as you can to make it watertight.
Every day, take off the sheeting, soak the patio, then cover it again. Do this for 7 days.
Experts say there is some downside to laying plastic on curing concrete. Sometimes concrete can become discolored where the plastic is touching it. If your ultimate plan is to stain or paint the concrete, then some discoloration won’t matter.
But if your plan is to leave the concrete as natural as possible, then try putting something tall (but lightweight) in the middle of the patio so the plastic will tent.
Or use t-posts or other fencing materials to build a framework to hold and elevate the plastic. Experts say another method is to lay straw down first, then the plastic.
What Happens if You Put Weight On Curing Concrete Too Soon?
Cracks. Weakened areas. Footprints and drag marks. You and your family’s footprints or handprints in the wet concrete may be charming, but the prints of your neighbor’s St. Bernard randomly walking around won’t be.
You should protect your newly poured patio from foot traffic – including pets – for at least 24 hours. Set out some chairs or t-posts around the outside of your new patio. Then string up some bright orange fencing, available at most big box hardware stores.
Add some CAUTION or CRIME SCENE tape around the area to make sure kids get the idea.
Most experts recommend waiting 3 days before you, your kids, and your pets walk on the patio.
Here’s our article on how to repair cracks in concrete.
What’s The Best Time of Year To Pour Concrete? (And at What temperature?)
The answer here depends on your climate. The ideal time of year in many places in late spring or early summer. Wait for the ideal curing temperature – not more than 75° F and not less than 50° F. Check for rain (or snow!) in the forecast and for windy weather. Neither of these are good.
For cement curing, the slower, the better. Cold and wind will dry out your slab too quickly and weaken it. Too hot and sunny can also be a problem. Sure, predicting the weather is tough, so plan ahead. Have plastic sheeting and blankets on hand.
If the weather unexpectedly turns cold and your patio isn’t cured yet, you may need to warm up your concrete. Concrete stops curing at 45° F. That means it will stop hardening. If your patio is only at 50% hard, that’s a big problem.
If the weather turns just a little too cold, you can try to lay out some heavy plastic sheeting. Often, this will be enough. Check the temperature with an outdoor thermometer.
If the temperature drops a lot, you can buy special concrete insulating blankets. But if you don’t want to make this investment – pile on the household ones.
Here’s a handy website with seasonal cement pouring tips, by region, throughout the US.
So remember – even though that newly laid concrete looks all smooth and enticing, you risk damaging the surface if you jump the gun.
It’s best to hang fire to let it cure for at least 2 days before walking on it, and 7-10 days before putting out your patio furniture.
And after 28 days your new concrete patio will be completely cured – so you can put what you like on it then (within reason!).