CHICAGO, Illinois (From the Post Dispatch) -- Building supplies maker USG Corp. said it would sell its distribution unit, L&W Supply Corp., to roofing supplier ABC Supply Co. Inc. for $670 million, as the company looks to cut debt and focus on its high-return gypsum and ceiling businesses.

The all-cash deal is expected to be completed before the end of 2016, the companies said on Monday.

L&W Supply distributes gypsum wallboard and other building materials in the United States.

The distribution business accounted for about 38 percent of Chicago-based USG's total sales of $3.78 billion in 2015.

Beloit, Wis.-based ABC Supply, which also distributes siding and windows, said the acquisition would help it expand in the business of supplying building interiors.

USG had $1.68 billion of long-term debt as of June 30, according to a recent quarterly filing.