Shares in building products maker James Hardie Industries (ASX:JHX) slumped to their lowest in a year after the company announced its outlook remained uncertain.

The stock shed 52 cents, or 8.44 per cent, to $5.64 by 10.47am (AEST), their weakest since August 13, 2009.

The US market, James Hardie's largest, was still weak, according to chief executive Louis Gries.

"The recovery in the US residential housing market remains disappointing and fragile," he said.

"Following the expiry of the US Government tax credit incentives at the end of April 2010, the gradual recovery of US residential construction, which had been apparent in the first four months of calendar 2010, stalled."

Mr Gries said annualised sales of new homes, at 549,000 units, in June 2010, were the weakest from April 2009, and were the second lowest since 1963.

He linked the continuing weakness in the US housing market to factors such as lower mortgage application rates and construction volume and weak builder sentiment.

James Hardie, however, bounced to a profit of $US104.9 million ($116.9 million) in the June quarter, from a loss of $US77.9 million in the first quarter of 2009/10.

Excluding the company's asbestos obligations, net operating profit was $US40.5 million, a 3 per cent decline on the previous corresponding period.

Net sales from ordinary activities climbed 12 per cent at $US318.4 million.

The upward shift came on better results in James Hardie's Asia Pacific operations.

James Hardie said growth in the Asia Pacific business "again contributed strongly this quarter.

"Corporate costs have also been reduced as the number of unresolved legacy issues diminish," Mr Gries said.

"These factors offset a downturn in US results in the quarter.

"The residential housing markets in Australia, NZ and the Philippines are expected to continue to improve through the first half of fiscal year 2011.

"However, softness in the renovation market and declines in the commercial market are expected to offset a significant portion of the stronger residential growth."