Revenue in the year to March 2020 jumped 27% to £116m, generating a 22% rise in pre-tax profit to £24m.
Flannery continued to pioneer innovation investing £44m in new hire equipment as it continued its push to promote modern methods of operating within the plant sector.
This saw the book value of machinery rise to £125m from £102m in the previous year.
Net cash increased from £11.5m to £17.4m helped by a lean operational cost base.
In the accounts, chief executive Patrick Flannery said: “The board remains optimistic for the forthcoming year and current performance supports this.
“In view of the Government infrastructure spending commitments and the strength of the financial position of the company, the board is confident that they can manage and take advantage of opportunities that may arise to increase market share.”