A spokesperson for Tesco said: "All 45 of the stores will be rebranded over the next year. They are quite different shapes and sizes to the Tesco Express layout."
The move is part of Tesco's strategy to increase its dominance of the UK supermarket sector. It recently raised £773m from the market, and is looking to raise nearly £1bn more from reorganising its working capital and sale-and-leasebacks of its substantial property portfolio.
Much of this cash would benefit contractors, as it would be spent on improving and building stores.
The spokesperson said: "We're talking to a few parties about the property element. We're due to make an announcement [later this year]."
A typical new-build supermarket can be worth about £4m to a contractor, and a fit-out can earn it up to £200,000.
The market is awaiting the closure of Morrisons' £3bn purchase of rival Safeway. The head of retail at one contractor said: "If the Safeway deal goes through, all the rebranding and reformatting means Morrisons will be taking a lot of work to the market."
The merger will give Morrisons a total of 552 UK stores, as well as nearly 16% of the grocery market.