The results are a turnaround on the same period last year which saw the company make a loss of £27.2m.
Turnover was steady at £1,148m as results for the full year were predicted to come in ahead of expectations.
Chief executive John Morgan said: “The Group has delivered strong profit growth in the first half, with an improved cash position and lower average net debt across the period.
“All divisions have contributed, demonstrating the strategic and operational progress made across the Group over the last few years.”
The construction and infrastructure division saw adjusted operating profits return to £3.2m on turnover of £612m managing a margin of 0.5%.
Morgan Sindall also reached a settlement deal during the period on the second of two legacy contracts inherited from Amec which had blown holes in previous results.
An exceptional charge of £39.6m was included in the restated construction accounts.
A search for a new chairman is also underway after Adrian Martin decided to step down.
