Markit's and the Chartered Institute of Purchasing & Supply's construction purchasing managers' index (PMI) for the U.K. increased to 58.1 in June from 55.9 in May, exceeding expectations for a rise to 56.5.
A reading above 50 indicates expansion in the construction sector.
The increase was driven by a rise in the house-building sector, but both commercial and civil engineering activity also increased.
"The extent of the recent rise in construction optimism is partly down to relief that pre-election uncertainty has now passed, but it also suggests that firms are infused with confidence that underlying demand will continue to recover," an economist at financial data company Markit, Tim Moore, said.