ARLINGTON — A Denver-based building materials supplier announced Tuesday that it will acquire Oso Lumber, Inc.

According to a statement released by ProBuild Company LLC, the supplier has reached an agreement to purchased the assets of Oso Lumber, which is based in Arlington.

The transaction is expected to close on April 30. Terms of the agreement were not disclosed.

“ProBuild is the clear market leader nationally, and ProBuild’s philosophies and goals are very much in line with those of Oso Lumber,” said Oso Lumber President Adam Lingenfelter in a release. “This acquisition gives the employees of Oso Lumber opportunities that were previously not available to them.”

Oso’s stores, located in Arlington, Ferndale, Granite Falls, Sedro-Woolley and Spanaway, as well as its truss plant in Arlington, will be known as ProBuild once the deal is closed.

Oso currently offers a range of services, including truss and wall panel manufacturing, window and millwork distribution and framing optimization.

The privately held corporation was started in 1978 by Mack and Frances Cook in Darrington, and over the years expanded to several locations throughout the Puget Sound area.

The Sedro-Woolley yard was added 1988. The following year, Oso’s corporate yard moved to its present location in Arlington.

The Cooks’ son, Mike, purchased the company in 1992, and Oso Lumber expanded into Granite Falls, Ferndale and Spanaway.

ProBuild Northwest President Ed Waite said the acquisition will allow the top two building material suppliers in the area to join forces.

“We are committed to giving Oso’s customers the outstanding customer service they have come to expect,” Waite said.

ProBuild operates more than 470 distribution, manufacturing and assembly centers in 42 states, and sells a number of building materials including lumber, plywood and trusses.