Shares in building materials producer Boral lost almost three per cent after it made a surprise cut to its full year profit guidance because of eastern Australia’s big wet.

Heavy rain has continued to hamper home building activity through the early stages of autumn, particularly in NSW and Queensland, causing Boral’s profit in the three months to March 31 to be $22 million lower than expected.

Boral shares lost 11 cents to $3.70 as a result of the profit downgrade.

“While any downgrade is disappointing it is the magnitude of this one that particularly galls,” Morningstar analyst Peter Warnes said.

Boral had previously forecast net profit before significant items in a range of $150 million to $175 million for the year to June 30.

But the 13-15 per cent profit drop in the three months to March takes that forecast down to the range of $128 million to $153 million.

Boral made a $167.7 million profit in the 2010/11 financial year.

“This reduction relates to continued heavy rain and lower residential housing activity on the east coast of Australia, particularly in Queensland and New South Wales,” the company said in a statement.

Mr Warnes said both Boral’s building products and construction materials operations would have been affected by heavy rains.

“Bricks, tiles and pavers and rain do not mix, neither does cement, concrete and aggregate,” he said.

Weather will remain a key variable for Boral in the final months of its financial year, the company said.

Boral said its United States and Asian results were broadly in line with expectations in the first quarter of calendar 2012.