Revenue rose 17% to reach £536m in the year to March 2024 due to growth in energy and water contracts, both through increased volumes on existing jobs and new wins.
The restoration of operating margin from 3.7% in the prior year helped to more than double pre-tax profit to £32m.
Headcount at the Manchester-based business also increased to 2,400 staff on the back of the growth.
Michael Porter, chief financial officer, said: “Our order book is strong following success in a number of new work tenders during the year, and also, work volumes are increasing on mature contracts.
“We are well positioned to embark on the next phase of our development through organic growth, selective bidding of new opportunities and potential acquisitions that will expand our range of services and our client base.
“Our focus wil remain on those markets where non-discretionary spending programmes exist to maintain critical infrastructure.”
At year end the business had £25m in cash.