X0508 4 2023-08-14 0 0001316835 Builders FirstSource, Inc. BLDR 0001837949 Hiller Michael C/O BUILDERS FIRSTSOURCE, INC. 6031 CONNECTION DR., STE. 400 IRVING TX 75039 0 1 0 0 President - Central Division 1 Common Stock, par value $0.01 per share 2023-08-14 4 S 0 5965 147.91 D 32892 D Common Stock, par value $0.01 per share 2023-08-15 4 S 0 1397 151.96 D 31495 D This transaction was executed in multiple trades at prices ranging from $147.17 to $148.47 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. This transaction was executed in multiple trades at prices ranging from $151.61 to $152.08 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. /s/ Minator Azemi, by power of attorney 2023-08-16