Chief executive Struan Robertson, who took over in January from Sir Christopher Wates, said the fit-out division had successfully taken on market leaders such as Interior and Overbury.
He said: "London is very competitive but for those who are willing to work with clients, there's still money to be made. We are able to offer a competitive service, especially in office and retail sectors."
Robertson said construction turnover was about £450m and said he also wanted to increase the Wates housebuilding business from its current 10% of group turnover. He refused to say what the new target was. Average selling price for its homes was £400,000.
He said it was increasingly difficult to secure good land and was moving the group more towards brownfield developments.
He said: "It's not easy to find the land. The planning system is slow, cumbersome and somewhat fickle.
If you have the land, you have the competitive advantage."