Peter Watson, chairman of the Lincolnshire-based contractor, said the market, particularly the developer-led sector, was sensitive to "macroeconomic sentiment".
He said: "Any general economic uncertainty leads to an almost immediate postponement of investment decisions.
"But likewise it is just as quickly reinstated once that uncertainty diminishes."
The group added that it had experienced a recovery last month.
Watson made the comments as Birse announced that it had made a profit after a year of losses. Birse posted a 拢1.2m pre-tax profit for the six months to 31 October, compared with a 拢6.7m loss for the same period last year. Turnover rose 拢52m to 拢244m.
The main improvement came in the construction division. Its civil engineering business, which recorded a 拢77,000 loss last year, turned in a 拢2.4m operating profit this year.
The group said the improvement was was because there were more opportunities in the rail, Tube, roads, flood defences and utilities markets.
The rest of the construction division (building and process engineering) posted operating losses of 拢102,000 and 拢2.2m respectively; last year the losses were 拢2m and 拢6m respectively.
The building division's results were affected by poor returns on two of larger contracts and a 拢335,000 loss because another contract was underpriced.
Overall, Birse's construction division posted an operating profit of 拢154,000 compared with a loss of 拢8.1m last year.
The group's order book on 31 October was 拢425m 鈥� up 拢63m on last year.
Watson said the results showed the company was continuing to make progress after it was faced with legal battles earlier this year in which 拢24m was at stake.
The group also announced that it was forming separate businesses in its civil engineering division, Birse Metro and Birse Rail, to target Tube and national rail clients.
