How hotter summers are affecting property developers

Extreme heat can put pressure on development costs, productivity and project timelines. Shawbrook research conducted in summer 2026 found that property developers estimated periods of extreme heat added an average of £213,617 to their costs.

The research followed the UK’s hottest summer on record, according to provisional figures from the Met Office, and highlights the practical considerations developers may face as they plan for periods of prolonged hot weather.

The cost of extreme heat for property developers

Property developers surveyed by Shawbrook estimated that extreme heat added an average of £213,617 to costs across their development projects.

More than half (52%) said their costs had increased because of essential temporary cooling measures, including heating, ventilation and air conditioning (HVAC) systems. A similar proportion (51%) reported lower productivity during periods of extreme heat.

Developers also reported technical delays involving building materials (50%), while 49% had temporarily stopped work on one or more projects. Just 2% said the summer’s weather had no negative impact on their projects.

How extreme heat can affect development projects

The impact of hot weather can extend beyond direct costs. When productivity falls, materials are affected or site activity needs to pause, this can affect project programmes and completion dates.

In Shawbrook’s research, 43% of developers said they planned to allow more time for projects to be completed in future. The same proportion said they planned to introduce additional health and safety protocols to protect workers during heatwaves.

More than a third (37%) planned to modify site designs to improve natural ventilation and shading, while 38% said they would avoid certain building phases during peak summer months.

Building climate resilience into future developments

Developers are also considering longer-term measures to help their schemes adapt to changing weather conditions.

Two in five (41%) said they planned to invest in climate-resilient building materials or technologies, while 36% expected to allocate more budget to climate-proofing measures.

When asked about their priorities for the following 12 months, 52% said they planned to install air conditioning or cooling systems in their developments. Other priorities included sustainable drainage systems (47%), water management policies (46%), measures to make developments compatible with electric vehicles (41%) and solar power (36%).

Managing changing costs and timelines

Terry Woodley, Managing Director, Development Finance at Shawbrook, said:

“This was an exceptional summer, but an estimated average additional cost of more than £200,000 shows the practical impact prolonged hot weather can have on development projects, affecting day-to-day work, timelines and budgets.

“The bigger picture is housing supply. When projects pause and completion dates slip, that’s homes arriving later in a country that needs more of them. The developers adapting fastest are treating heat like any other project risk – pricing it into contingencies, phasing the heaviest work away from peak summer and building resilience in from the design stage. And where costs or timelines do move, the earlier that conversation happens with a lender, the more options stay on the table.”

If costs or timelines change during a development, early conversations can help developers understand the options available. Explore Shawbrook Development Finance.

About the research

Research was conducted among 500 professional property developers aged 21 and over between 14 and 25 August 2026. Professional property developers were defined as individuals who develop property as a business or occupation, rather than those undertaking occasional or personal development projects.