Shares in Boral have jumped to a four month high after the building materials maker's half year profit was bolstered by stronger construction activity in Australia and improving earnings in the US.

The company’s net profit in the six months to December 31 rose 12.3 per cent from a year earlier to $153.4 million. That was despite revenue dropping 4.6 per cent to $2.09 billion, due to the completion of several large projects and accounting matters related to its Meridian brick joint…