How to protect concrete from rain and frost |

April 12, 2023

It is not an easy task to do concrete work in this world where the weather changes all the time and can be quite unpredictable. Being in charge of a project where fresh concrete is placed means that you have to be prepared for whatever the weather throws at you. 

So how can you protect the concrete from different weather conditions? In this article we will explain how to protect concrete from rain and frost. These are two very common issues when it comes to concreting. Which is why we have gathered all the information you need to save your concrete work from unnecessary damage. 

Read more: Learn more about the long term effects of hot weather and cold weather on concrete.

Concrete in relation to rain and frost

Both rain and frost can have negative effects on freshly poured concrete. Rain can compromise the concrete mix ratio which will weaken the concrete. Frost during the first 24 hours since placing the concrete will also compromise the strength of concrete. 

If you wanna learn more about what happens when concrete freezes and how to place concrete in rainy weather you should check out our articles. 

How to protect concrete from rain

Protective precautions

There are some important steps to take before concreting during a particularly rainy season. These will help ensure that you are always prepared and will also minimize the risk of having to redo any work. 

  1. Always keep an eye on the weather forecast
  2. Make sure all the material needed to cover up the worksite is nearby and easy to grab
  3. Remove any rainwater from the worksite before starting to pour the concrete

Protection during concreting

There are two things you can do to protect the concrete if it were to start raining in the middle of placing the fresh concrete. 

  1. Create a shelter over the worksite by using plastic sheet and timber
  2. Keep an eye on the concrete and remove any excess water that might find its way through the protective covers.

Protective measures to take after placing concrete

If you managed to get all the work done and the fresh concrete is now in its place, the last thing you want is for a sudden downpour to ruin it all. To avoid that possibility, here are some things you can do. 

  1. Place plastic sheets and tarpaulin over the freshly poured concrete to protect the whole area
  2. Keep those covers on for at least 4-8 hours, the longer the better

Read more: Read up on underwater concreting, concreting in humid climates and how to pour concrete in freezing conditions.

Rain gathering on the ground

How to protect concrete from frost

Protective precautions

In order to give the concrete a chance to reach its full strength, and get the best possible outcome you should prepare the worksite by following these steps. 

  1. Make sure that you allow the ground on the worksite to thaw before pouring concrete
  2. Use thermal blankets or heaters to speed up the thawing process

Protection during concreting

If the temperature drops down right before or during the concreting process it is important to act quickly to minimize potential damage. 

  1. Do not take any long breaks during the pouring and try to be as effective as possible to speed up the process
  2. Install windbreaks if there are cold winds that may affect the concrete

Protective measures to take after placing concrete

There are many different methods to make sure the freshly poured concrete stays warm during the entire curing process. Choose one or many that will work for you. 

  1. Measure the temperature of the concrete at all times
  2. Insulation
  3. Hydronic heaters
  4. Heated enclosure
  5. Thermal blanket

Read more: We help you figure out what weather is best for concreting and give you our best tips for concreting in hot weather

Frequently asked questions

At what temperature should you cover fresh concrete?

Concrete should preferably be kept at a temperature above 10C. This means that if the temperature is lower than 10 it would be a good idea to cover it up. However, it is even more important to cover up if the temperature drops below freezing.

Should you cover concrete with plastic in cold weather?

Yes, it is a good idea to cover concrete with plastic in cold weather to restore the heat while the concrete continues to cure.

How long should fresh concrete be kept wet?

The goal is to keep the concrete wet for the entirety of the curing process. This process takes about 28 days during which the concrete develops its strength.

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