Do you have a thermometer in your tool box?

As we're sure you're aware, we're going through a cold patch at the moment. 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.

If you aren’t sure then a great reference source is LABC Warranty's Appendix C (Materials and Modern Methods of Construction). This provides greater guidance on minimum safe working temperatures.

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.

Further information

https://info.labcwarranty.co.uk/technical-manual-apc

How to protect your masonry from frost and rain

^{Please Note: Every care was taken to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the dutyholder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.}

^{This article was reviewed and updated on 10 August 2023}