What is the best time of year to pour concrete?

Pouring Concrete In Cold Weather

Freshly laid concrete that freezes within the first 24 hours of pouring can lose a whopping 50% of it's strength overall. Generally, if the weather is below 5°C and there is ice or snow on the ground, then it is too cold to pour the concrete.

But... if you have to install concrete in colder weather then you need to ensure it is protected straightaway to avoid damage.

Readymixed concrete should not be less than 5°C when delivered on a cold day as there is a risk that it can be damaged. Additionally you can protect concrete by:

• Using an air entrained admixture to increase the freeze/thaw resistance - our staff will happily advise
• Using Insulated Formwork or Timber Formwork
• Using Frost Blankets, temporary covers and even space heaters

Pouring Concrete In Wet Weather

It probably goes without saying that wet weather is generally not the best weather in which to pour and lay concrete, however, in the UK the weather is not only temperamental at the best of times but also rather unpredictable so the rain can't always be avoided!

Generally if too much rain water gets into your concrete mix then it's overall strength could be put at risk. If possible we would recommend waiting for a clearer day, however, if you have to install concrete in wet weather here are a few things you can do to protect it:

• Do not pour concrete into water-filled cavities or directly on to very wet surfaces. Ensure they are cleared first.
• Cover your concrete with tarpaulin or a waterproof cover
• Ensure any surface water is pushed off the edge of the slab and make sure it's covered afterwards
• If it rains after pouring your concrete make sure it's adequately protected and covered

Pouring Concrete In Hot Weather

On the other-hand... hot and dry weather can also have an adverse affect on your concrete. Generally concrete requires water as an essential component - so the higher the temperature, the faster water will evaporate and compromise the integrity of your concrete.

Hot and dry conditions can cause your concrete to crack as a result of the speed in which concrete solidifies. This will cause problems with strength and durability. But there are things you can do to protect your concrete if you have to pour and lay it on a hot day, including:

• Avoid laying concrete at peak temperature times (typically between 11am and 3pm - but can vary).
• Ensure the concrete is covered with a plastic sheet for shade once laid. This will help to prevent water from evaporating too quickly whilst the concrete cures.
• Use concrete retarding admixtures to slow down the curing process - our professionally trained staff are happy to advise you on this.
• Make sure you have sufficient manpower to help with the pour and laying of the concrete