Extreme heat added an average of around £214,000 to property development costs this summer, according to research from development finance lender Shawbrook. The Met Office's provisional figures show the UK's hottest summer on record.
More than half of developers (52%) said temporary cooling measures such as HVAC systems pushed property development costs up, and 51% reported lower productivity. Technical delays involving building materials affected 50%, while 49% had to pause work on at least one project. Only 2% said the weather had no negative impact on their projects.
With hotter summers expected to become more frequent, developers are changing their plans. Some 43% will allow more time for completion, and the same proportion plan to introduce extra health and safety protocols to protect workers during heatwaves.
More than a third (37%) will modify site designs to improve natural ventilation and shading, while 38% plan to avoid certain building phases during peak summer months.
Longer-term resilience is also on the agenda. Two in five (41%) plan to invest in climate-resilient building materials or technologies, and 36% expect to raise the budget allocated to climate-proofing.
Asked which measures they will prioritise over the next 12 months, 52% said they plan to install air conditioning or cooling systems in their developments. The other priorities were:
- sustainable drainage systems (47%)
- water management policies (46%)
- measures to make developments compatible with electric vehicles (41%)
solar power (36%)
"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," said Terry Woodley, managing director of development finance at Shawbrook.
"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."
