Do you have a thermometer in your tool box?

09.02.2021

Blog Post

If you're a builder or a tradesman, how does the cold affect your tools and materials?

It’s well worth remembering that two degrees is the minimum working temperature for most materials. It's very important to take regular temperature readings when working during cold weather periods. For consistency, thermometers shouldn’t be placed in direct sunlight, but preferably in a shaded area. Don’t forget to factor in wind chill and weather exposure as they can mean a significant drop in temperature on exposed sites.

Frozen materials should never be used in any circumstances. So cover your bricks, blocks, sand and cement to protect them. Please, please don’t try the ‘old washing up liquid trick’ - this really is a dangerous myth. It won’t improve frost resistance but it will reduce the strength of your wall.

Any newly built walls or other masonry construction will need protection against frost when temperatures drop below 2°C. This can be with polythene, but hessian is much better. If temperatures are expected to drop well below zero then insulation boards can be used against the masonry and heating may even need to be considered.

Rendering work is probably the most vulnerable and should only be done when the temperature outside is at least 2°C and rising with no frost anticipated prior to adequate curing. It shouldn’t be applied onto a frozen surface either.

No plastering or screeding should take place unless the building is free from frost. You can use internal heating to warm the building but it’s important to provide ventilation to allow moist air to escape. You should also pre-heat the building before plastering and as the plaster dries.

Thermometers might be a little too delicate to survive in the average toolbox but most phones now have an app that will let you know if the temperature is 2 degrees and above. Remember to use it when we get the next cold spell.

^Disclaimer:

^{Every care has been taken to ensure that the above content is correct at the time of publication.  Any reliance on the content should be verified by the dutyholder(s) and their professional advisers.  It is the responsibility of the dutyholder(s) and/or person carrying out the work to ensure compliance with the relevant building regulations and associated legislation.}

^{This content is given in good faith by LABC.  It is not definitive and compliance will be a matter for the relevant building control authority to decide as the enforcing body for the building regulations, and ultimately for the appropriate tribunal or court to determine.}

^{This article was updated on 15 May 2025.}