The building business fell into the red after a £13m profit in 2010 and underlined how fiercely competitive the UK building market has become.
Building accounts for half of Vinci group turnover in the UK and gained market share over the year as sales edged up.
The building division’s southern and eastern regions now have been restructured and the airport business brought under its management.
Vinci also launched a new commercial fit-out arm for an expected upturn in 2013-14.
Operating profits also fell at the Taylor Woodrow civils division leading to the slump in group pre-tax profits to £19.8m on turnover ahead 8.5% at £1.1bn.
Vinci plc divisions
Building: loss £2m (£13m: 2010); turnover £587m (£546m: 2010)
Civil engineering: profit £11.5m (£21m); turnover £206m (£179m)
Facilities: profit £6.2m (£5.1m); turnover £226m (£220m)
Other: profit £1.2m (loss £3.3m); turnover £93m (£81m)
Vinci continues to push for market share and picked up a record £1.3bn haul of orders last year and 61% of this year’s expected orderbook.
Chief executive John Stanion said the group was forecasting 2012 turnover will be up 11% and would require 400 more staff over the year.
He said that efforts to strengthen business development had lifted its building bid hit-rate to one in three tenders, up from one in five the year before.
But Stanion also warned: “The prevailing economic conditions and increased competition are also having an effect on margins.”