Quinn’s broadside came as the skills body faces its triennial consensus vote which it needs to win to allow it to continue collecting levy cash from contractors.
Quinn attacked the CITB for failing to train enough workers, being too big, bureaucratic and unaccountable.
He added: “Balfour Beatty is likely to vote against Consensus.”
But now it is all change following weeks of lobbying by the CITB and leading trade bodies who are keen for it to continue.
In a statement Balfour said: “Last month Balfour Beatty set out its concerns over the lack of clarity ahead of the triennial CITB consensus vote.
“Since then, Balfour Beatty has held a number of further meetings with the CITB.
“The CITB has now provided Balfour Beatty with appropriate assurances and preliminary details about the reforms.
“It has demonstrated that it understands the urgency and magnitude of change necessary to create a CITB which will better meet the needs of the UK construction industry and help create the skilled workforce necessary to deliver the enormous pipeline of planned works.
“Balfour Beatty believes that further work on the governance of the CITB is necessary. We are willing to work constructively, with the CITB and our industry partners, to ensure that the CITB has governance which is fit for purpose as soon as is practical.
“It is unsatisfactory that the vote on the consensus is taking place before full publication of the reform plans.
“This has meant that industry has had to vote without having the detail it needs to make an informed decision.
“Nonetheless, in light of the assurances received from the CITB and its management Balfour Beatty has decided to vote in favour of the consensus to enable the CITB to rapidly deliver on these commitments.”
Sarah Beale, CEO of CITB, said:“We welcome today’s announcement from Balfour Beatty and agree that CITB’s reforms must make us more accountable to industry.
“Our discussions with Balfour Beatty reflect how we want to go forward with industry, with open lines of communication and agreed outcomes.
“There is no doubt change needs to happen. All levy payers should know that we are listening to them and will adapt to support their needs now and in the future.”