UPDATE 1-Builders FirstSource Q2 loss wider-than-expected

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July 31 (Reuters) - Builders FirstSource Inc (BLDR.O), a maker of building products for new residential construction, posted a wider-than-expected quarterly loss as sales declined amid a housing market slump and slowing U.S. economy.

The company posted a net loss of $45.9 million, or $1.29 a share, compared with a net income of $8.4 million, or 23 cents a share, a year earlier.

Excluding asset impairment charges and a tax valuation allowance, the company lost 37 cents a share.

Sales fell 34 percent to $307.3 million.

Analysts on average expected a loss of 35 cents a share, before special items, on revenue of $299.7 million, according to Reuters Estimates.

The company said it expects the difficult market conditions to hurt its results throughout the remainder of 2008 and 2009. Increased competition arising from the current operating conditions could have a negative impact on margins, Builders FirstSource said.

Shares of the Dallas-based company closed down more than 9 percent at $4.37 Thursday on Nasdaq. (Reporting by Eric Yep in Bangalore; Editing by Pratish Narayanan)