Under the initiative, due to start later this year, six union safety representatives will visit sites throughout the country to give advice.
Last year, a row broke out between UCATT and the Construction Confederation after the confederation refused to support a pilot roving reps scheme. However, the idea received a boost last year after the success of two trial schemes in London and the North-west.
UCATT general secretary George Brumwell said that the initiative would be UCATT-led but noted that many companies had agreed to support it.
Brumwell said: "The safety advisers will be unique. Because they are not on any employer's payroll they will be independent and able to offer sound advice.
"This is a chance to really improve safety in the industry."
Construction Confederation chief executive Stephen Ratcliffe said that the scheme would not provide a yardstick for measuring improvements in safety standards.