One in eleven people (9%) in the UK, or about five million, leave their sheds and outbuildings unprotected, even though 29% had been victims of theft, according to research from Aviva.
Two-thirds (67%) of those who had their shed or outbuilding broken into also had a break-in or attempted break-in at their home.
Claims data from Aviva showed the average claim for shed or outbuilding theft in 2024 was £4,205.
Even so, more than three in five (62%) did not check if their shed or outbuilding was secure before going on holiday or leaving home overnight, and 63% did not check before going to bed.
One in six (16%) left sheds or outbuildings unlocked when gardening or doing chores, which could increase the risk of theft and make it harder to claim on insurance.
One in six (16%) people regularly stored valuable items in their shed or outbuilding.
Bikes and electric bikes were the most commonly stolen (24%), followed by garden tools (20%) and power tools (16%).
Replacement costs for these items were £2,056 for bikes, £1,299 for garden tools, and £2,038 for power tools.
Fishing equipment was the most expensive to replace at £2,418.
The top items stolen included bicycles and electric bikes (24%), garden tools (20%), power tools (16%), electronics (12%), children’s toys (11%), food or drink (11%), gym equipment (11%), personal mementos (11%), outdoor furniture (10%), sports or hobby equipment (9%), and indoor furniture (9%).
One in eight (13%) used their outbuilding as a workshop, and 10% used it as a space for exercise.
Other uses included hobbies (8%), running a business (6%), bars (7%), games rooms (6%), offices (6%), and TV rooms (4%).
Hannah Davidson, senior underwriting manager, home and lifestyle at Aviva, said: “Our research suggests that burglars may be more inclined to target a home if they first gain access to an unsecured shed or outbuilding, so it’s worrying to see many residents failing to take any security measures.
“Although it may be tempting to leave doors and windows open, thieves only need a small window of opportunity.
“Even basic things like a sturdy lock or motion-activated lighting can be enough to deter someone from trying to break into your garage or outbuilding, such as a shed.”
Davidson added: “Most home insurance policies will also have a limit on how much cover they’ll provide for items stolen from a garage or outbuilding, so it could be worth checking your policy and considering alternative storage options for more expensive items.
“In the event you do not properly lock up your home, garage or outbuilding, you may be unable to make a claim in the unfortunate event you become a victim of theft.
“This is because most insurance policies will stipulate that you must properly secure your home.”
She said: “With the average claim being £4,205, it’s worth spending five minutes double checking before you leave your home, even for a short period of time.”
