Markit's and the Chartered Institute of Purchasing & Supply's construction purchasing managers' index (PMI) for the U.K. declined to 54.2 in February from 55.0 in January, missing expectations for an increase to 55.5. It was the lowest level since April 2015.
A reading above 50 indicates expansion in the construction sector.
The index was driven by a softer growth in output, new orders and employment.
Housing activity showed the slowest performance since June 2013.
"UK construction firms remained in expansion mode during February, but a loss of momentum within the residential building sector meant that overall output growth was the weakest since April 2015. Aside from the pre-election slowdown last year, the latest upturn in construction output was the weakest for over-two and-a-half years," Senior Economist at Markit, Tim Moore, said.