The PMI, which indicates business growth with numbers above 50, dropped from 56.7, a 12-month high, to 55.8, but remained "comfortably above the 50.0 no-change mark," said the monthly report, which is co-produced by Markit Economics.
The overall index has now indicated growth in construction in Britain for each month since January 2011. It has remained above the break-even point despite Britain posting two quarters of negative economic growth overall, which is the standard definition of a recession.
The report for March said growth was "again led by work on commercial projects," which, in turn, contributed to a second consecutive month of increased construction employment.
The report divides construction into the three major categories of housing, commercial construction and civil engineering.
Commercial construction posted the strongest numbers for the month, followed by civil engineering.
For the second consecutive month, growth in residential construction was "only marginal," Markit said.