Homeowners considering building a home improvement such as a conservatory or garden study may be interested to hear the latest Lloyds TSB figures.
The financial institution advised its customers to avoid using unqualified tradesmen after finding more than 4.6 million botched jobs have been reported in the past year.
It discovered one in ten Brits has been forced to correct substandard work in the last 12 months – a 16 per cent rise on last years figures.
While the average price of these fixes was £460, it is possible the cost a large job such as a kitchen extension could be even more if carried out incorrectly.
"Rogue traders are on the increase and costing unsuspecting homeowners thousands," explained Lloyds TSB Insurance managing director Phil Loney.
He added the company has produced a guide to "rooting out the rogues" to help its customers choose a reputable home improvement company.
Last month, the firm reported a rise the number of homes supporting three generations of the one family – a phenomenon that may give homeowners cause to extend.