Markit's and the Chartered Institute of Purchasing & Supply's construction purchasing managers' index (PMI) for the U.K. increased to 55.9 in May from 54.2 in April, exceeding expectations for a rise to 55.0.
A reading above 50 indicates expansion in the construction sector.
The increase was driven by a rise in new orders, which grew for the first time in three months.
Residential building activity rose in May, commercial construction slowed to the lowest level since August 2013, while civil engineering work grew.