The engineering construction and maintenance specialist based in Motherwell said it made progress on most projects last year, including design and build of data centres and cleanroom facilities.
Revenue at Bouygues E&S Contracting UK across the year rose 9% to £130.6m.
But two loss-making contracts where technical difficulties resulted in project delays tipped the firm £4.7m into the red last year.
The firm is understood to be still nursing fallout from two biomass projects. One of the projects was a flagship gasification facility in Hoddesdon, Hertfordshire. The £60m advanced conversion treatment plant was expected to become operational in early 2017.
This saw Bouygues E&S Contracting UK plunge £50.5m into the red in 2018. The year before that the firm lost £33.5m.
Bouygues Energies & Services division’s larger hard and soft FM business faired better with revenue up a fifth to £231m generating a 50% jump in pre-tax profit to £10.3m.