When the weather forecast calls for rain, it can be tough to decide whether to proceed with a concrete project. Even though water is a fundamental component of concrete, pouring it in the rain can be a tricky proposition and one that most people are reluctant to attempt.

Normally speaking, concrete is a mix of water, cement, and additional aggregates. Moisture in the form of water is essential for the chemical reaction that cures it. But we know that excess of everything is bad! When the concrete is freshly placed, rain can pose serious risks and challenges for its pouring and curing, including reduced bonding, slower setting, or scaling.

Once the damage is done, the rectification sometimes gets out of hand. Hence, the answer to whether it’s ok to pour concrete in the rain is not straightforward and depends on multiple factors.

Risks of Pouring Concrete in The Rain

The major risk associated with concrete pouring in the rain is that it alters the composition by diluting the mixture and weakening the foundation. This happens because rainwater has a high Oxygen content and low pH as compared to normal tap water. This can impede the hydration process and reduce the overall resilience of the concrete.

Besides that, rainwater holds impurities and chemicals that can influence the quality and appearance of the concrete surface. Moreover, rain can affect the bonding between the new and the existing concrete surfaces.

When concrete falls on freshly poured concrete, it builds a film of moisture that prevents both the new and old layers from adhering properly, resulting in scaling and cracking over time, particularly if the temperature changes or the concrete undergoes heavy loads or freeze-thaw cycles.

The Gains of Pouring Concrete in The Rain

On the other hand, pouring concrete can manifest some benefits too that can outlay the risk of certain situations. For instance, if the weather is extremely hot and arid, rain can help to keep the mixture moist for a desired time and prevents quick drying. This boosts the curing process and increases the durability of concrete.

Also, rain can be a blessing in disguise in such extreme temperatures as it cools down the concrete for god. It reduces the risk of thermal cracking, which can occur when the temperature disparity between the surface and the core is too high.

What Are The Conditions for Pouring Concrete in The Rain?

To decide whether to pour concrete in the rain or not, you need to take the following conditions into account.

• Intensity:

Drizzling rain does not usually concern the concrete in contrast with heavy rain. If the rain is pouring heavily, it can wash away the cement paste, expose the aggregates, and create a porous and fragile surface. Consequently, it is ideal to wait until the rain halts or slows down.

• Temperature:

The optimal temperature for pouring concrete is 5-35°C. If the rain is too cold or too hot, it can intrude on the natural chemical reaction and impact the curing time and stability of the concrete. Additionally, if the temperature drops below freezing point, the water molecules in the concrete can freeze as well, causing it to crack.

• Protection:

If you decide to go for concrete pouring in the rain, you need to take some protective measures to alleviate or minimize the risks. For that, you may cover the area with any plastic sheet or tarp. Some additives and accelerators can also be added to the mixture to speed up the setting time and equalize the excess water.

The Alternatives To Pouring Concrete in The Rain

In case the conditions are not promising and you are not satisfied with pouring concrete in the rain, these are some alternatives you may consider.

• Postpone The Project

If there are chances for extended rain or there is a heavy thunderstorm approaching, it is ideal to wait for a bright sunny day or at least a dry day. This will need rescheduling of the contractors, adjustment of the budget, extension of the working timeline, etc., to refrain you from future expenses.

• Use ready Mix Concrete

If you are going to pour concrete in a specific shape, you can go for ready-mix concrete. It is also known as pre-cast concrete that is cured by optimizing specific environmental conditions. It is then transported in the ready form to the site of construction, conserving time and struggle and decreasing the risks associated with on-site mixing and pouring in rainy weather.

Some Tips for Pouring Concrete Rain

• Plan Ahead: Check the weather forecast and plan accordingly.
• Adjust The Mix: Use a concrete mix that accounts for the excess water from rain. Besides, add some admixtures or accelerators.
• Cover The Surface: Use any plastic, tarp, or non-porous covering to protect the mix.
• Monitor The Temperature: Utilize a digital thermometer to check the temperature of ambient air and concrete.

Bottom Line

In a nutshell, pouring concrete in the rain is alright as long as you take the proper precautions. Prevention is better than cure. Hence you need to plan early and according to the circumstances.

If you’re in search of some good quality concrete for your next project, Pro-mix Concrete is your best choice. We specialize in providing premium quality cement with ready-mix and unique blends for any sort of project, So, Stop worrying about the quality – let us take care of it for you!