Landlords and property investors are being warned that the current heatwave could trigger a wave of costly structural damage, putting rental stock, insurance premiums and maintenance budgets under serious pressure.
Property preservation specialists Timberwise say sustained high temperatures pose a significant and often undetected threat to property condition, one that can rapidly turn minor maintenance issues into major liability.
The warning carries precedent. When the UK recorded temperatures above 40°C for the first time in 2022, insurers paid out an estimated £219m in heat-related property claims. Around 18,000 additional claims were linked to subsidence and structural damage, as prolonged dry conditions caused clay-rich soils to shrink and destabilise building foundations. Experts warn a similar picture could emerge if the current hot spell extends.
"Landlords often focus on damp, mould and winter weather as their main maintenance risks, but sustained heat can be equally destructive, and the damage tends to build up quietly," said George Edwards, managing director at Timberwise.
"Small defects that appear harmless in spring can escalate quickly during a heatwave. By the time a tenant reports cracks, sticking doors or water ingress, the repair bill can already be significant."
Risks to rental stock
Subsidence ranks among the most serious threats, particularly for properties on clay-heavy ground across much of England. As moisture evaporates, soil contracts and foundations can shift unevenly, presenting as cracks around windows and door frames, rippling interior walls, or sticking doors and windows.
Roofs deteriorate rapidly under sustained UV exposure. Repeated expansion and contraction weakens seals, flashing and fixings, while asphalt shingles can blister or curl, and flat roofs may soften and become prone to water ingress. This is a particular concern for HMOs and converted properties with large flat roof sections.
External finishes, including render, masonry, uPVC frames and sealants, are also vulnerable, with warping, cracking and failed weatherproofing all common outcomes of prolonged heat exposure. In poorly ventilated properties, loft spaces can reach extreme temperatures, placing additional strain on electrical systems and stored equipment.
What landlords should do now
Timberwise recommends landlords carry out landlord property maintenance inspections before temperatures peak, focusing on:
- Roofs, guttering, flashing and masonry, identifying small defects before they worsen
- Loft ventilation, to reduce heat stress on roofing and timber structures
- Foundation moisture, by gradually watering the soil around the perimeter during prolonged dry spells to help stabilise ground conditions
- Sealants, caulking and external finishes, ensuring weatherproofing remains intact
- Driveways and paths, repairing asphalt cracks and clearing concrete expansion joints
"Early intervention is always the most cost-effective approach," Edwards added. "A straightforward inspection before summer peaks can prevent what might be a £500 issue becoming a £5,000 one, and keep properties safe, habitable and compliant."
