Sir Robert McAlpine made a pre-tax loss of £89.7m for 2013/14, citing “weaknesses” that led to project delays and cost escalations.
In its accounts for the year ended 13 October 2014, the family contractor pointed to “one project in particular” that made losses but did not name the scheme.
It said 2014 had been a “challenging year” and added that some sectors were suffering from high cost escalation and a “very stretched and limited supply chain”, particularly in London where it has a strong presence.
It added: “The significant deterioration in the performance is the result of a number of poorly performing contracts which has incurred considerable losses.
“The company has taken a prudent view of the final outcome of these contracts and has not allowed for any recoveries that may be expected in the longer term.”
The contractor said it had now “reviewed and corrected” problems within the business, including the restructure of its management framework and the introduction of “new and robust governance procedures”.
Revenue stood at £787.8m for the period, compared with £780.4m the year before.
Its pre-tax loss of £89.7m compared with a £4.4m profit in 2013.