With another spell of hot weather forecast, it’s a good time to remind ourselves that the biggest risk on site isn’t just the sun – it’s the effect heat has on our bodies, concentration and the quality of our work.
Stay Safe on Site
Working in hot weather can lead to dehydration, heat exhaustion and, in severe cases, heat stroke. Even mild dehydration affects concentration and reaction times, increasing the risk of accidents.
Some simple precautions can make a big difference:
- Start demanding tasks as early as possible before temperatures peak.
- Drink water regularly – don’t wait until you feel thirsty.
- Take more frequent breaks in shaded or cool areas.
- Wear lightweight clothing where appropriate, along with suitable PPE.
- Apply high-factor sunscreen to exposed skin and reapply during the day.
- Look out for your workmates. Early signs of heat illness include dizziness, headache, muscle cramps, excessive sweating and confusion.
If someone becomes confused, stops sweating or loses consciousness, treat it as a medical emergency and call 999 immediately.
Hot Weather and Masonry
Heat doesn’t just affect bricklayers – it also affects the materials.
High temperatures, strong sunshine and drying winds can cause mortar to lose moisture too quickly. If mortar dries before the cement has fully hydrated, the bond strength can be reduced and shrinkage cracking may occur.
To achieve the best results:
- Protect mortar from direct sunlight before use.
- Mix only what can be used within the recommended working time.
- Dampen very dry, highly absorbent bricks where appropriate (they should never be saturated).
- Avoid laying masonry during the hottest part of the afternoon whenever possible.
- Protect newly built masonry from direct sun and rapid drying using suitable coverings.
Remember that cement needs water to cure properly. Faster drying is not the same as faster curing.
Did You Know?
- There is no legal maximum working temperature for outdoor construction work in the UK. Employers must instead assess the risks and introduce suitable control measures.
- Heat stress is affected by more than just air temperature. Humidity, direct sunshine, heavy manual work and PPE all increase the risk.
- Dehydration of as little as 2% of body weight can significantly reduce concentration, decision-making and physical performance.
- Mortar performs best when it is allowed to cure naturally. Rapid drying in hot weather can reduce bond strength and increase the likelihood of cracking.
A little extra planning during hot weather helps protect both the workforce and the quality of the finished masonry.
Heat Safety Checklist
✔ Drink water little and often
✔ Work in the shade where possible
✔ Take regular breaks
✔ Watch for signs of heat exhaustion
✔ Protect fresh masonry from rapid drying
✔ Look after your mates
