Mears sold its dedicated M&E arm Haydon to its management for £1 back in 2013.
The deal included a five year period for cash to be recovered by Mears.
But the company said today: “Our original expectation was that the post disposal period would experience a cash in-flow for the Group which up to December 2014 had been the case.
“However, the carrying value of amounts recoverable has been reassessed and the Group now anticipates writing off in full all unsecured amounts.
“This exceptional item is expected to be in the region of £8 million including a cash out-flow of circa £4 million.”
In a trading statement Mears confirmed a strong performance in its core social housing market while conditions in the care sector remain “challenging”.