Major orders helped to raise revenue by 6% to £167m generating a pre-tax profit of £3.2m.
The improved performance helped to lift margin from around 0.9% to 1.9%, still below major UK rivals.
The uplift saw the workforce grow to 624 staff.
Group CEO David Hodgkiss said: “Demand in the UK for structural steelwork products remains at an encouraging level.
“The company has a very strong order book and is confident that the level of activity will continue in the short to medium term.
“The directors consider the financial results for 2018 to be a reasonable performance considering the markets it is involved in.”
The wider group, which includes international activities and its business Cellbeam, raised revenue by 8% to £221m, generating £3.5m pre-tax profit.