Revenue for the year to 30 September fell to £164m from £216m previously.
But directors said the group remained resilient, underpinned by stable margins, repeat business and strong cash reserves.
EBITDA came in at £6.5m, and margins edged up to 4% from 3.5%.
Cash at bank closed the year at £12m with net assets raised to £20.5m from £17.6m.
Chairman James Coffey said: “We’re incredibly proud of the result given the challenges in the market.
“The group’s future order book and pipeline remains strong as the business focuses on continuing to work with both new and long-established clients.
“Consistent with the previous year, to ensure the business has a diversified and secure revenue generation, we have continued to prioritise the growth of our infrastructure, data centre and structural alterations, including the builders work and fire protection elements of business.”