It’s that time of year. The walls are stacked and braced on a self-build outside Okehampton, the ready-mix is booked for Thursday, and the forecast shows minus two overnight. Construction UK Magazine ran a piece on 11 November with Travis Perkins setting out six cold-weather checks for site teams, and the first one is simple: look at tomorrow’s programme the night before and work out what the frost could affect.
Concrete is top of that list. The article points out that young concrete can be seriously damaged if the water in it freezes, and that low temperatures slow down strength gain. Common UK guidance is to keep fresh concrete protected until it reaches about 5 N/mm². With open timber or ply shuttering the core is exposed on both faces. With Nudura, there’s 67mm of EPS either side holding in the heat the concrete gives off as it cures, which is one reason ICF pours can carry on later into the autumn than conventional formwork.
That isn’t a licence to ignore the weather, mind. The top of the wall is still open, so cover it once it’s levelled off. Check the forms are clear of ice and standing water before the pump arrives, never pour onto frozen footings, and have a word with the batching plant about the mix if it’s going to be properly cold.
Then think about the materials sitting in the yard. Bagged cement, foam adhesive, illbruck tapes and render basecoats all have their own temperature limits, and the article is right that there’s no single figure for everything. Go by the technical data sheet. And remember a wall can still be frozen at 10 o’clock even when the air feels mild.
Last one, and it matters round here. A loaded concrete wagon on a frosty single-track lane near Bratton Clovelly or Lifton needs a gritted route and room to turn before it sets off. If you’d like to talk through pour planning or bracing on a Nudura build, The Fell Partnership is on 01822 890251, or have a look at thefellpartnership.co.uk.
