Group turnover for the period rose from £933m to £959m.
Mowlem chief executive Sir John Gains said: "At the moment we're quite comfortable with our order book, and see some good opportunities in infrastructure. The board is confident that our results for the year as a whole will be in line with expectations."
Mowlem is also preferred bidder on £2.4bn of PFI projects. These include a 25-35-year joint venture with US contractor Kellogg Brown & Root to build and maintain the Allenby and Connaught barracks in Wiltshire and Hampshire.