Overall group turnover decreased from £223m to £204m, with construction accounting for most of the fall as revenues at the business dropped 28% to £81m.
Losses at the construction arm were contained to £650,000 last year, improved from losses of £2.8m in 2019 and £2.5m in 2018.
The construction business entered 2021 with clear books after negotiating away further commercial risk on two loss-making contracts.
It is now run by John Hartnett, who was promoted to managing director at the start of this year, and is back on track to return to profit this year after a strategic decision now to avoid risky single-stage design and build jobs.
Profits at the group, which now employs nearly 700 staff, were largely driven by continued growth of commercial and residential property, and a resilient performance from water and FM operations.
Group managing director, Jeremy Hartley said: “The strength of our underlying business and the commitment and determination of all our staff has enabled us to trade through the pandemic and look to the future with a cautious optimism.”