In news that may encourage brick tools specialists, the organisation said it "continued to perform well" following an "excellent" 12-month period throughout 2009.
Covering the period from January 1st 2010 to May 6th, the report noted the company remains resilient, despite challenging economic conditions.
"As a result of a number of significant new contract awards since the beginning of the year, the group has maintained its order book at the record year-end level of £2.6 billion," it remarked.
According to the firm, it is has reached more than £950 million in revenue over the last five months, while obtaining more than £600 million in preferred bidder positions.
The document stated the enterprise's board expects this year's performance to be in line with expectations, following strong ongoing development strategies.
A recent Costain project in the county borough of Rhondda Cynon Taf, South Wales, created 70 jobs - including groundworkers and land surveyor assistants.