Jarvis and Amey have already changed their accounting methods.
In a trading statement, Carillion said earnings per share for this year would not be affected by the changes. This is because of a lower-than-expected tax charge and increased savings from a restructuring programme last year.
Carillion added that it had secured £1bn worth of contracts in the first half.
The contractor announced that its subsidiary Carillion Services had won a £50m, seven-year contract to supply services to hospitals in Lincolnshire, the largest of its type.
BAA has also selected Carillion's M&E arm Crown House Engineering as one of two companies for a £200m, seven-airport contract.