While a common assumption that pouring concrete in wet/rainy weather presents more favourable curing conditions, see Sephaku Cements top tips and tricks to pouring concrete in rainy climates making sure your concrete pouring project is a solid success.

As one of South Africa’s provinces moves from a hot and wet summer, another one of our provinces are lined up for a cold and rainy winter which means inevitably South African concrete contractors will all be required to pour concrete in wet and rainy conditions at some time during the year. While concrete and water go together like a hand in glove, there are very specific guidelines that should be followed under wet and rainy conditions to make sure the integrity of your concrete project is not compromised by unpredictable summer thundershowers or weeklong soft soaking rains. As with so many things in the concrete construction business, success is largely put down to the timing of things, whereby with planning and a little bit of forethought, even the most disastrous conditions need not stop your progress.

Plan Around Weather Forecasts

While it’s neither a fool-proof method nor wise to place all of your faith in the weather forecast, a good place to start is by planning your concrete pouring project around expert weather predictions. With a number of resources that offer a near accurate seven to ten-day weather forecast begin by keeping a close watch on the coming weather predictions planning your project around the drier days than on the scheduled wet ones. No matter how much pressure your project may be under, it’s always a smarter choice to postpone pouring until drier conditions if the weather forecast predicts wet/rainy weather.

Unpredictable Thunderstorms

In the case of an unpredictable summer thunderstorm, hard and fast rain can negatively affect newly poured concrete, causing the surface to become over saturated and soft, compromising the overall strength and increasing the risk of cracking once cured. If your concrete project has been poured within a few hours of a fast-moving thunderstorm try to protect the surface of the concrete by erecting a temporary shelter above the worksite even if this is effective enough to deter just some of the downpour.

Sweep Away the Excess

Once a sudden downpour has come to an end, never try to blend excess rainwater into poured concrete, remember that the correct water to cement ratio must be adhered to in order to ensure the concrete cures with its required strength. Provided that doing so won’t damage or deface the desired finish, try to push or pull excess water from the surface of recently poured concrete. If the concrete was placed between four and eight hours prior the rain setting in, you need not be concerned with removing any excess water from the surface.

Pouring Concrete After the Rain

While waiting for the rain to subside before placing new wet concrete, it’s important to note that wet concrete should never be poured into a hollow filled with water or cavities and groves that are filled with remaining water or runoff. By doing so, much in the same way as rain falling and pooling onto the surface of concrete, concrete poured into a puddle of rainwater will adversely affect the water to cement ratio compromising the strength and consistent curing of your concrete project.