Balfour has sought to shore up cash and profitability in Britain as the infrastructure sector gets fewer contracts since the country voted to leave the European Union.
The company also increased its annual cash forecast, supported by lower costs, higher margin projects and a rare encouraging outlook in the beleaguered industry.
Construction activity in Britain shrank for a third month in a row in July as Brexit worries hit building projects, heightening concerns that the slowdown could spill over into other areas of the economy, a survey showed.
The FTSE 250 listed company increased its annual cash forecast by about 50 million pounds to between 280 million pounds and 300 million pounds and said pretax profit rose to 64 million pounds for the six months ended June 28 from 56 million pounds a year earlier.
"At UK Construction, there is plenty of disheartening data but Balfour, like Costain, is there for the survivor's photo," Liberum analysts said.
Infrastructure firm Costain expects lower full-year revenue as it had been hit by delays in contracts starts, but its order book grew, helped by new project wins.
London-based Balfour, which is working on projects that are part of expanding Heathrow Airport and the Hinkley Point C nuclear power station, said underlying profit from operations at its domestic construction business rose to 17 million pounds from 5 million pounds a year earlier.
Balfour worked on projects including a M4 Smart Motorway contract, the A14 in Cambridgeshire - UK's largest current road project, HS2 and Hinkley Point C.
Balfour's total order book rose 5% to 13.2 billion pounds.
It said decisions to proceed with the HS2 high-speed rail network and Heathrow airport expansion would significantly improve its outlook.
"Investors in embattled construction firm Kier or those unlucky enough to be shareholders in Carillion when it went bust must be looking at today's first half results from rival Balfour Beatty and turning green with envy," AJ Bell investment director Russ Mould.
Mould added that growth was pinned on the infrastructure developments projects.
Balfour shares rose 8.9% to 219.8 pence at 0921 GMT.
Balfour will stockpile housing materials to battle Brexit-driven delays and has a "Brexit clause" in contracts, Chief Executive Officer Leo Quinn told Reuters.
"Our contracts take into account the fact that the likes of Brexit could cause delays, which could have a financial impact ... we don't remain liable for any financial consequences associated with Brexit delay," he said.
The company, which operates a 50-50 joint venture based in Hong Kong, said there could be slight administrative delays in delivering contracts because of the clashes between police and pro-democracy protesters.
The company also said it would not currently change short term financial forecasts after allegations of falsified maintenance records at two U.S. air force bases.
(Reporting by Samantha Machado and Noor Zainab Hussain in Bengaluru; Editing by Bernard Orr and Alexandra Hudson)
By Samantha Machado and Noor Zainab Hussain