Extreme heat is already affecting construction projects across the UK, with new research finding that 58% of tradespeople have had their work negatively affected by hot weather. For anyone planning a self build, increasingly frequent heatwaves could mean changes to working hours, project delays and potentially higher costs.
The UK’s increasingly hot summers could have implications for people building their own homes, as extreme temperatures are already disrupting work for tradespeople across the country.
Research by Rhino Trade Insurance found that 58% of tradespeople have had their work negatively affected by hot weather this summer, with more than a quarter of jobs either postponed or cancelled because of the heat.
The findings come after successive heatwaves between May and the end of July 2026, when temperatures reached as high as 38°C. A separate report estimated that these heatwaves had an economic cost of at least £4.4bn, partly due to reduced productivity.
Heat slows construction work
For self builders, one of the most immediate concerns is the potential impact on project timescales.
Of the 1,079 tradespeople surveyed by Rhino, 70% said they had been working at a slower pace in the heat. Almost 40% had experienced delays to project timelines, while 70% said they had clocked off early when temperatures became too high.
More than a quarter of tradespeople said they had postponed jobs because of the heat, while 38% had changed their working hours. Of those changing their hours, 77% were starting work earlier in the day to avoid the hottest part of the day.
The effects aren’t limited to outdoor work. More than half of the tradespeople surveyed mainly worked indoors, with more than a third saying they had moved jobs indoors to avoid the heat.
Heat can affect materials and working conditions
Extreme temperatures can also create challenges around the construction process itself. 16% of tradespeople surveyed said that materials had been affected by the heat, while 186 of the 1,079 people surveyed had either suffered a heat-related illness themselves or knew a colleague who had. Reported examples included dizziness and heatstroke.
Outdoor trades such as building, roofing and gardening can be particularly challenging during periods of extreme heat, with risks including dehydration and exhaustion.
For someone managing a self build, this could mean allowing more flexibility in the construction programme rather than assuming work will continue at the same pace throughout the summer.
Could extreme heat become a bigger issue for self builds?
The research suggests that this may not simply be a short-term problem.
According to official sources including the Met Office, heatwaves are expected to become more frequent, longer-lasting and more intense. Rhino’s survey found that 42% of tradespeople said extreme heat was becoming a growing concern for their ability to work.
The UK currently has no maximum working temperature, although 64% of the tradespeople surveyed believed there should be one.
For self builders, the findings highlight another factor to consider when planning a construction programme. As periods of extreme heat become more frequent, working hours, project schedules and the conditions in which tradespeople can safely work may all need to be taken into account.
With fewer workable hours potentially leading to delays and increased costs, allowing some flexibility into the build programme could become increasingly important for projects taking place during the summer months.
