Concrete is one of the most commonly used and durable building materials. It’s known for its strength, but its long-term performance depends on its proper curing. Concrete hardens through a chemical reaction known as hydration. During this process, cement reacts with water to form a solid structure. 

So, while it doesn’t necessarily have to be warm for concrete to cure, too much water can dilute the mix, impact the integrity of the structure and slow down setting time. Concrete will begin to set in a few hours, but it can take several days to cure fully.

In this article, we explore if concrete will set in the rain, how excess water from rainfall can affect the curing process and what to do if it unexpectedly rains after you’ve poured concrete. 

How rain can affect concrete going off

Freshly poured concrete needs moisture to help with the curing process, but too much water from rain can lead to some problems. These issues include: 

A weak surface layer: If rainwater dilutes the mix too much, it can result in a soft, powdery or crumbly finish. 

Cracks or patches: If rain pools on your freshly poured concrete, it can pool in some spots and cause the concrete to crack or become patchy. 

Discolouration: Heavy rain can wash away cement particles, resulting in an uneven appearance with dark and light patches. 

Reduced strength: If there is too much water and the bonding is affected, then your structure’s strength can be compromised.  

Can you pour concrete in the rain? 

While it is not ideal, it is possible to pour concrete in the rain, but it’s essential that you take some precautions first. If heavy rain is forecasted, then you may want to delay the pour. Make sure you have plenty of plastic sheeting and tarps to cover the surface and protect it from rain.

If you’re expecting rain and cannot delay the pour, then you may want to consider adjusting the mix by adding less water to allow for extra moisture. Finally, if you can slope the surface, this can help the water run off instead of pooling on your freshly poured concrete. 

What to do if it rains after you’ve poured concrete

As we all know, sometimes the weather in the UK can be unpredictable. If it rains unexpectedly after you’ve poured your concrete, don’t panic. Here are some steps you can take to minimise the risk: 

Cover the surface immediately. 

Check for damage after it stops raining.

Repair any damage with a thin resurfacing layer.

Are you looking for a concrete supplier? 

If you are planning a home improvement project or a commercial build and need ready mixed concrete pumped in, please get in touch with Erris Concrete. Our experienced and friendly team are on hand to answer your questions and help you determine the type of mix you need and the quantity. No matter your requirements, we can help you find the right solution.

Contact us today on 01327 206 650 or complete our contact form.