About 70,000 construction workers employed by councils are set to strike this month in a row over pensions.
The workers, which include those represented by UCATT, Amicus and the GMB, were part of a national ballot of 1.5 million public sector workers that voted overwhelmingly in favour of strikes to take place on 28 March.
The dispute, set to be Britain's biggest industrial walkout since 1926, centres on the government's attempts to remove the so-called "85-year-rule" from October. The rule allows workers to retire at 60 on a full pension if their age and years of service total 85. The government wants to raise this age to 65.
Alan Ritchie, UCATT general secretary, said: "Our members work in a pressurised and physical part of local government, and the nature of the work they undertake impacts on their health. That is why it is important to retain the right to retire at 60 years on a full pension."