Tips on Pouring Concrete in the Rain
Article Updated: 18/10/2019
When you want to pour concrete and find yourself up against the pouring rain instead, what should you do? There are multiple reasons for pouring concrete in the rain, like being located in a consistently inclement climate, having a particularly wet winter or having to stick to a tight schedule.
It’s a fact that professional concrete layers are capable of pouring concrete in the rain, so what steps do they take to ensure that concrete can be poured no matter how wet the forecast? Let’s find out.
Concrete doesn’t ‘dry’ it cures
People refer to concrete ‘drying’ before standing on it but this is incorrect. Concrete doesn’t dry, it cures. Curing is a chemical reaction that takes place over the concrete’s lifetime and it’s what gives concrete the ability to cure underwater.
That’s right, concrete can cure underwater and become strong with the right conditions in place and when being poured by a professional. However, pouring concrete in the rain is different. This example simply demonstrates how versatile concrete is and how often people misunderstand concrete’s relationship with moisture. Concrete can also be affected by cold temperatures, which is worth considering when pouring concrete during winter.
Concrete setting & curing time
Concrete can take 24 to 48 hours to set and around a week to partially cure. During this time, walking on the surface is allowed. However, due to the nature of concrete consistency, it is best to avoid heavy equipment during this period. This will ensure no damage is caused to the surface. Typically, concrete can take 28 days to fully cure, however, it continues to cure indefinitely throughout its lifespan.
How concrete layers pour in the rain with great results
- Good drainage: this ensures no rainwater pools in trenches dug for footings, foundations and slabs. This is important, as rainwater can bring with it contaminants. So long as it drains away there won’t be a problem with pouring concrete in the rain.
- Taking measures to cover concrete that is aesthetic: using covers and tarps will protect small slabs. A self-levelling compound can be applied later if necessary to smoothen the surface. Tarps and covers can also be used for larger areas to good effect.
Never do these things when pouring concrete in the rain
- Never work large amounts of rainwater into the concrete mix as it cures, this will introduce contaminants into the mix.
- Never spread dry cement on the wet surface to ‘soak up’ the rainwater as this will create a poorly finished surface.
Here’s what to do if it starts raining unexpectedly while pouring concrete
Heavy rain can cause problems to freshly poured concrete as it can wash out some of the cement from the mix. This can weaken the surface of the concrete, making it a softer consistency and decreasing the strength of the concrete.
Problems such as concrete cracks and a delay in curing time can come as a result of working in the rain. However, there are precautions that can be taken to ensure rain doesn’t affect your pour:
1. Check the weather forecast before pouring the concrete and prepare accordingly if you are pouring independently. If there’s rain expected and you’re having a professional do the job, you can ask your concrete layer how they will be prepared for this.
2. Cover with tarpaulins or waterproof covers that cover the area to be poured. Keep these on standby and apply as each area is ready to leave for curing.
3. Push any surface water off the edge of the slab, then cover with a large tarp.
4. If it rains straight after the concrete is poured, act promptly to ensure the area is covered.