By Grant Prior.Construction workers are reluctantly accepting an increased pay offer of 2.5 per cent.Votes were canvassed on site last week and union leaders were expected to accept the deal formally at a meeting of the National Joint Council for the Building Industry yesterday (Wednesday).Private sector building and civil engineering employers came up with the improved offer last week. The previous offer was 1.2 per cent.Minimum rates of pay for a normal 39-hour week will rise to £163.41 from £159.51 for craft operatives, and to £139.23 from £135.91 for labourers.The increases will come into effect from June 27.George Henderson, the construction secretary of transport union TGWU, said: 'Obviously we are not too happy about a settlement like this, but we have to look at these things rationally in the current market.'And general union GMB national officer Allan Black said: 'You can't say this is a good offer, but it's better than last year when there was a pay freeze.'Significant progress was also made last week on plans to overhaul the industry's wages structure.Employers are pushing for a revamp of the National Building and Civils Working Rule Agreement by the end of next month to come into force by July 1995.A source said: 'There was a much larger measure of agreement than expected last week.'We are meeting again towards the end of June and it looks like something fairly concrete will come out.'Proposals under discussion include phasing out the weekly tool allowance and replacing it with a one-off payment.The unions want higher insurance for workers' tools on site.The source said: 'Cover for tools is around the £350 mark which is unrealistic these days.'People like carpenters and joiners regularly carry around tools worth nearly £1,000.'The pay deal for Britain's 600,000 construction workers mirrors recent settlements in the heating and ventilating and plumbing sectors.