Households are being warned not to store certain cleaning products in garages and sheds as temperatures continue to soar across the UK. Many homeowners keep cleaning sprays, aerosols, disinfectants, and solvents in outbuildings such as garages, sheds, utility spaces, or cupboards under the stairs, often to keep strong smells out of the house.
Garages as Heat Traps
During summer, this practice can become dangerous as experts say these storage areas can become far hotter than many people realise during periods of extreme heat. Improper storage raises the risk of heat damaging items, which can cause leaks or even lead to aerosol cans bursting.
According to basement specialist Ryan Gorenflo from The Basement Doctor, garages in particular can act as "heat traps" during warm weather, creating conditions unsuitable for a range of temperature-sensitive household products. "A garage can become a heat trap during a heatwave. In my experience, people often assume the garage is cooler because it is not part of the main living space, but that is not always true," he explained.
Dangers of Pressurised Containers
Gorenflo added that many garages lack ventilation and insulation, meaning heat can build up quickly throughout the day. "That means items stored inside can be exposed to far higher temperatures than people expect," he said. The biggest concern is pressurised containers such as cleaning sprays, air fresheners, insecticides, aerosol paints, and similar products. While most are designed to be safe when stored correctly, they can become dangerous if exposed to prolonged heat.
"Any pressurised can should be treated carefully in extreme heat. If a product label says to keep it away from heat, direct sunlight, or high temperatures, a garage or shed during a heatwave may be the wrong place for it," Gorenflo warned. In severe cases, containers can leak, rupture, or even burst if temperatures become too high. However, not every household product is at risk; the issue is mainly about where people choose to store them.
Temperature Swings and Storage Tips
Garages, sheds, and lofts tend to experience more extreme temperature swings than the living areas of a home that benefit from ventilation, shading, and regular airflow. "A garage is different. It can sit closed all day, with heat building up inside. If the door faces the sun, the temperature can rise quickly," Gorenflo explained. High shelves and metal storage units can make the problem worse, as heat rises and metal retains warmth.
Beyond cleaning products, Gorenflo advised homeowners to check other stored items, including paint tins, batteries, electronics, candles, soft furnishings, documents, and pet food, all of which can be affected by heat or humidity. "Paint is one of the most common items I would move first," he said. "Batteries and old electronics should also be kept somewhere cooler and dry, because heat can shorten their lifespan."
Simple Checks During Heatwave
The expert urged homeowners to carry out a simple check during the heatwave: "Read the label first. If it says a product should not be exposed to heat, do not leave it in a garage during a heatwave. If something looks damaged, swollen, or leaking, don't ignore it."
Gorenflo also warned about storing cardboard boxes on concrete garage floors when temperatures rise. "Cardboard absorbs moisture very easily. Heat alone is not usually the main problem with cardboard, but heat combined with humidity, poor ventilation, or damp concrete floors can make boxes soften, smell musty, or hold moisture against the items inside. That can ruin clothes, books, documents, photos, and soft furnishings before homeowners realise anything is wrong," he said. He recommends moving important items into sealed plastic containers and keeping them raised off the floor where possible.
