X0306 4 2018-03-01 0 0001316835 Builders FirstSource, Inc. BLDR 0001389137 Tolly Morris E 2001 BRYAN ST., SUITE 1600 DALLAS TX 75201 0 1 0 0 SVP - COO - East Common Stock, par value $0.01 per share 2018-03-01 4 A 0 19467 0.00 A 128344 D Common Stock, par value $0.01 per share 2018-03-01 4 F 0 4304 21.19 D 124040 D Common Stock, par value $0.01 per share 2018-03-05 4 M 0 50000 3.19 A 174040 D Common Stock, par value $0.01 per share 2018-03-05 4 S 0 50000 21.25 D 124040 D Employee Stock Option (right to buy) 3.19 2018-03-05 4 M 0 50000 0.00 D 2020-02-03 Common Stock 50000 0 D Reflects the acquisition of restricted stock units pursuant to the Corporation's 2014 Incentive Plan. The restricted stock units vest in 33.3% increments on each of March 1, 2019-2021 and entitle the reporting person to one share of common stock for each restricted stock unit that vests. Reflects shares withheld to pay tax withholding requirements on vesting of previously granted restricted stock units. This transaction was executed in multiple trades at prices ranging from $20.98 to $21.61 per share. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide full information regarding the number of shares and prices at which the transactions were effected upon request by the SEC staff, the issuer, or a security holder of the issuer. Award issued under the Company's 2007 Incentive Plan, as amended and restated on January 14, 2010. The option was granted on February 3, 2010 and vested in 33.33% increments on each of February 3, 2012-2014. /s/ Jeffrey A. Wier, by power of attorney 2018-03-05