Construction sites are not ready for extreme heat

Hot weather is already having a negative impact on UK construction workers’ health and wellbeing and most construction sites are not set up to protect them, researchers have found.  

Construction management experts asked workers and their managers how heat affects them personally at work, and what is being done to keep them safe. They collected 307 answers from people working for medium and large construction firms between April and September 2025, made up of 106 site workers and 201 managers.  

A report published today (Thursday, 25 June) by construction management researchers at the University of Reading found that 67% of the site workers are concerned about the impact that heat has on their health, with 44% of them saying that they have experienced a heat-related illness (such as heat stroke, heat exhaustion, or dehydration), and 50% reporting knowing someone at work also being affected. They also indicated feeling more tired (87%), annoyed (58%) and less concentrated (61%) when the weather is hot.  

Dr Alba Fuertes, from the School of the Built Environment at the University of Reading, led the research. She said:   

"Heat is already a danger for workers on construction sites and other outdoor workplaces on warm days, not a problem for some distant summer. Workers are experiencing heat-related illnesses, getting more tired, and losing focus, yet there is no legally defined maximum workplace temperature to protect workers from excessive heat in the UK.   

“In the absence of clear regulatory guidelines, together with an awareness gap, our study shows that heat adaptation is done based on personal experience and responses to heat remain inconsistent and insufficient across the sector. As our summers get hotter, sites need to proactively adopt effective measures and become more resilient to increased temperatures. Without effective measures and more awareness, construction firms could be putting lives at risk by allowing work to continue in dangerous conditions to workers' health."  

The study also found:  

• Discomfort and difficulty with tasks start at 20 to 25°C for more than four in ten of those surveyed, temperatures that are now common in a UK summer.  

• Less than one in five (18%) site workers said the protective clothing they wear in summer is suitable for hot weather. Only 27% had been provided with effective personal cooling equipment such as cooling vests or packs.  

• More than half (57%) of workers said they had received no compulsory training on how to deal with heat. 

• Only 37% of workers and 57% of managers felt confident they could act correctly if someone showed signs of heat stroke.  

• Heat is having a measurable impact on project delivery and costs. Nearly half of managers (48%) reported that heat causes programme delays, while 55% indicate that it results in costs they had not planned for.  

• Most people take action to protect themselves and others from heat risks based on their own experience rather than from training or official guidelines. Personal experience was the most common source of information for both groups, named by 78% of each.  

• The report found that managers and site workers do not always agree on how prepared sites are against heat. Managers tend to report that protective measures are in place and working, while the workers themselves often say they were not available or ineffective. For shaded rest areas, 67% of managers saw them as effective, compared with 47% of workers. The gap suggests that protections do not always reach the people who need them.   

The researchers warn that as summers get hotter, the risks will grow unless the construction industry is better prepared. They call for clearer official guidance and a maximum workplace temperature, practical training, and proactive planning and budgeting so that protecting workers from heat becomes a normal practice within the operational management of a construction project.