Power of Attorney for Matthew Coley O'Brien

This filing documents a Power of Attorney granted by Matthew Coley O'Brien, Chief Human Resources Officer of Builders FirstSource, Inc., to Alena Brenner and Minator Azemi. The authorization allows the attorneys-in-fact to execute and file all necessary statements and forms with the SEC, including Forms 3, 4, 5, and 144, related to Builders FirstSource, Inc. securities, under Section 16 of the Securities Exchange Act of 1934 and Rule 144 of the Securities Act of 1933. This arrangement remains in effect until O'Brien no longer has filing obligations or until explicitly terminated in writing. O'Brien acknowledges that the responsibility for compliance remains with him.