The firm said forward orders were up 10 per cent to £3.2 billion in the first half of the year as it secured more than £700 million of new contracts and extensions.
Costain said it was ramping up its dividend by a third, as adjusted pre-tax profit climbed eight per cent to £9.1m with revenues growing 14 per cent to £529.1m.
New contracts included an appointment to Network Rail's £2bn electrification programme as well as work on a section of London's Crossrail project. It also won a further commission with energy giant Centrica for its Barrow gas terminals project in Cumbria, as well as work for National Grid.
Chairman David Allvey said a capital raise of £70.3m this year had helped take advantage of opportunities "to accelerate the group's development". Costain announced an interim dividend of 3.25p compared to 3.75p last year. It said that on the basis of the enlarged share capital it represented a 32 per cent increase in the pay-out to shareholders.
The 150-year-old business has previously worked on a series of high-profile projects including London's St Pancras station redevelopment and the Channel Tunnel rail link.
Current work includes a nuclear decommissioning project at Sellafield, maintenance at Longannet power station in Fife and the redevelopment of London Bridge station for Network Rail.