The UK is set to sizzle in a heatwave this week, with temperatures expected to reach 34C in some areas. But homeowners are being advised to check their garages, sheds and lofts for one common item that could be ruined by the heat10:45, 24 Jun 2026Temperatures are set to surpass 34°C on Wednesday across parts of the UK. Meanwhile, red weather warnings have been issued for areas of southern England on Wednesday and Thursday.‌The UK Health Security Agency (UKHSA) has issued its own red heat health warnings, encompassing the West Midlands, East Midlands, South East, South West, London, and East of England. However, homeowners are being advised to inspect their garages, sheds and lofts during the heatwave, as one commonly stored item could be damaged by the soaring temperatures.‌Paint tins are frequently left in garages for years following decorating a room or an outdoor area.‌But according to Ryan Gorenflo, a specialist at The Basement Doctor, leftover paint is among the first things Brits should relocate from hot garages and sheds during extreme summer conditions.He cautions that many people regard garages as secure storage areas, without recognising they can become significantly hotter than the rest of the property during a heatwave, reports the Express.‌Ryan said: "Paint is one of the most common items people leave in garages, sheds and lofts, but it does not cope well with extreme heat or big temperature changes."If paint is stored somewhere too hot, it can separate, thicken, dry out around the edges or become much harder to use later. By the time you open the tin for a simple touch-up, it may already be ruined."Why garages can pose a problem in hot weatherGarages, sheds and lofts are frequently poorly insulated and inadequately ventilated, which means they can warm up rapidly during the day and retain heat for hours on end. This can spell trouble for items that need to be kept in cooler, dry and stable environments.‌Ryan explained: "A garage can become a heat trap during a heatwave. People often think of it as an extension of the home, but it usually does not have the same temperature control, airflow or insulation as a living space."That means items sitting on shelves, floors or in cupboards can be exposed to much harsher conditions than people realise."He warns the problem becomes even more severe when items are kept near windows, in direct sunlight, against hot walls or tucked away inside metal cabinets.‌Ryan added: "If the tin feels hot to the touch, or it has been sitting in direct sun inside a shed or garage, that is a sign it should be moved. Leftover paint should be kept sealed, upright and stored somewhere cool and dry, away from direct heat."Paint is not the only item to moveWhile paint tins are the main concern homeowners should be checking, Ryan stresses they're far from the only things at risk of damage in a sweltering garage.Article continues belowAerosol cans, batteries, electronics, candles, family photographs, important documents, cleaning products, cardboard boxes and soft furnishings can all deteriorate in high-heat or humid conditions.Ryan said: "The heatwave is a good reminder to treat the garage like a storage risk zone. If you have not looked through it for months, now is the time to check what is actually being kept in there."Some items can be ruined by heat, some can be damaged by humidity, and some simply should not be kept in spaces that get extremely hot."