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Laying foundations in bad weather
Keeping your self-build on track in bad weather
2019/2020 is set to be one of the mildest, wettest weather in years. In fact in February, England had more than 200 per cent of its average February rainfall and some areas got a month's worth of rain in less than 24 hours, making it the wettest February since records began, according to the Met Office.
So, with all this endless bad weather, how does it affect self-builders?
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.
As well as rain, it's also important to consider how the colder temperatures overall might affect construction projects. Even though we are now in March, temperatures can still plummet to minus figures, meaning weather with frosts, even moving into the Spring, can be detrimental to the concrete pouring process, but with careful planning and guidance you can avoid pitfalls and problems, and lay perfectly strong foundations - whatever the weather - for your self-build.
Cold weather
The biggest potential problem you could face during winter and spring builds, is that the concrete could freeze, causing the surface to be cracked or uneven. This could also happen during the concrete curing process, when the temperature of the concrete needs to be maintained for around 48 hours to ensure optimal strength. So don't forget, even when temperatures are optimal during the day, they can drop at night, so the addition of a heated enclosure may be a good investment.
When it rains, can you pour? (concrete)
Many people ask whether you can safely pour ready mix concrete in the rain? The answer is yes, it is absolutely possible to pour in the rain, but ideally you should avoid. Rain presents challenges, so doesn't always mean that your schedule is out of the window, as long as you take proper action.
What if it starts raining whilst I am pouring concrete into foundations?
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:
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.
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.
Push any surface water off the edge of the slab, then cover with a large tarp
If it rains straight after the concrete is poured, act promptly to ensure the area is covered.
It can take up to 28 days to fully cure ('dry), however, it continues to cure indefinitely throughout its lifespan.
https://www.everreadymix.co.uk/news/tips-on-pouring-concrete-in-the-rain/
https://www.telegraph.co.uk/news/2020/02/29/storm-jorge-latest-news-weather-forecast-floods-travel/