Winter doesn’t need to bring things to a grinding halt, but there is more to consider when pouring concrete in cold weather than doing the same on a mild spring morning. For one, you’re not usually worried about frost in spring which can be expensive, because a slab that freezes too early often must be broken out and poured again, yet it is almost always avoidable.
At NMSB, we are a local, BSI Kitemark-accredited supplier of high-quality concrete. We supply ready mix concrete in Hampshire and Dorset from plants across both counties. Most winter failures trace back to two things: placing on frozen ground and leaving fresh concrete unprotected overnight. So, let’s discuss what can be done to ensure a successful pour, even when the temperature is down in the low single digits.
We’ll begin with the most obvious question, and that’s ‘can you pour concrete in cold weather?’. Yes, provided you understand what the cold is doing to the mix. Concrete gains strength through a chemical reaction between cement and water, and low temperatures slow that reaction right down, so a winter pour hardens more slowly than the same pour in summer.
The greater danger comes when the water in young concrete freezes, because it expands. So, will frost damage fresh concrete? It can, by breaking up the surface and weakening the structure before it has gained any real strength, which is why laying concrete in winter is about keeping the mix warm enough for long enough.
Concrete Society guidance gives two figures to remember: concrete should be at least 5°C on delivery, and it should stay above 5°C until it reaches 5 N/mm² (MPa). And meeting those numbers starts with the forecast.
With those figures in mind, pouring concrete in cold weather is planned well before the lorry leaves the plant. What is the lowest temperature to pour concrete? In practice, the mix should arrive at no less than 5°C, with ground, formwork and reinforcement at least 2°C. If you are laying a sub-base first, our construction aggregates can be compacted in good time.
Before delivery day:
With the site ready, the next conversation to have is about the mix itself.
A well-prepared site is only half of the picture, because the mix matters just as much when you are pouring concrete in cold weather. When you book a winter pour with us, tell our technical team about the application, the forecast, how long you will need to finish and when you expect to strike formwork.
Those details help us advise on specialist and custom mixes, and on the minimum temperature for pouring concrete that makes sense for your job. Our in-house team also carries out cube testing, where small cubes are cast from a batch and crushed at set ages to confirm the concrete has reached its required strength, and our cold weather concreting experience means you are never starting from scratch.
The same conversation applies whether you need ready mix concrete in Dorset or Hampshire, screed or liquid screed. If you would like to use our sustainable low carbon concrete, ask our team which mix suits a winter pour.
Once the concrete arrives, pouring concrete in cold weather becomes a race between finishing and frost. How do you protect concrete from frost? You keep the heat in, which comes down to a few habits on site:
People often ask the question, ‘how long does concrete take to cure in winter?’, and the honest answer is longer than in summer, so allow extra time before you strike formwork or load the slab. That patience is what makes concrete in winter perform as well as a summer pour.
Protection on site only works if the concrete arrives when you need it, which is why ordering deserves as much thought as placing. Start with our concrete volume calculator so you order the right quantity, then book early and confirm access, because a delay at the gate costs heat.
On larger pours, pumped concrete shortens placing time, which suits the discipline of cold weather concreting. Ready mix concrete stays workable for roughly 1.5 to 2 hours after batching, so a local plant makes sense for ready mix concrete in Bournemouth, for example. We deliver in adverse weather by arrangement, though we advise talking to us about conditions in advance, and we offer out-of-hours deliveries on request and collection from our depots.
Our ISO 9001 and ISO 14001 accreditations sit behind all of it. Before you confirm, check the forecast against the minimum temperature for pouring concrete and your plans for frost protection for concrete.
Winter pours go well when you plan, protect and talk to your supplier early. Whether you are pouring concrete in cold weather on a small base or a large slab, we can help with ready mix concrete in the New Forest and beyond.
Use our contact form or call 01425 610 566 to get in touch. You can also open a trade account or view our full concrete range, for added benefits and to explore what we offer.