Sean Sullivan, 46, of Adelaide Close, Waddington, and Paul Sullivan, 41, of Sailsbury Close, Saxilby, each admitted a charge of obtaining property by deception in the sum of £155,452 from Balfour Beatty between November 2005 and October 2009.
Mark Knowles, defending Paul Sullivan, said the guilty plea was based on £64,319.
Sean Sullivan also admitted three further fraud charges on different dates between November 2009 and March 2011.
Judge Sean Morris granted bail, pending probation reports, at Lincoln Crown Court last Friday. They will be sentenced later. He warned: “These are very serious matters. On the face of it the only outcome is custody so you have some time to get your houses in order.”