Output in the UK's construction sector 3.6% in March and 1.1% over the first quarter, according to official figures which add to the increasingly concerning picture of the UK economy.
The 3.6% figure was the worst monthly fall since December 2012, and it falls below analysts expectations of a 2.5% decline.
Compared with the first quarter of 2015, output was down 1.9%.
The Office for National Statistics (ONS) said the amount of new construction work fell by 0.6% between the final quarter of 2015 and first of 2016. And repair and maintenance work also dropped 1.9%.
These figures come amid a range of surveys showing slowing growth in various parts of the UK economy. Earlier this week, the ONS reported that manufacturing factory output suffered its biggest annual fall since 2013 in March. Economic growth dropped to 0.4% in the first quarter of the year, and the UK's trade deficit rose to its highest level in six years.