Washington, D.C. 20549


Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB Number: 3235-0287
Estimated average burden
hours per response: 0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person*
Rush David E

(Last) (First) (Middle)
2001 BRYAN ST., SUITE 1600


(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Builders FirstSource, Inc. [ BLDR ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
SVP - COO - East
3. Date of Earliest Transaction (Month/Day/Year)
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock, par value $0.01 per share 11/05/2019 M 12,000 A $7.67 54,886 D
Common Stock, par value $0.01 per share 11/05/2019 S 12,000 D $24.53(1) 42,886 D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (right to buy)(2) $7.67 11/05/2019 M 12,000 (3) 02/11/2024 Common Stock 12,000 $0.00 19,108 D
Explanation of Responses:
1. This transaction was executed in multiple trades at prices ranging from $24.46 to $24.62 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.
2. Award issued under the Company's 2007 Incentive Plan, as amended and restated on January 14, 2010.
3. The option was granted on February 11, 2014 and vested in 25% increments on each of February 11, 2015-2018.
/s/ Jeffrey A. Wier, by power of attorney 11/06/2019
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

KNOW ALL PERSONS BY THESE PRESENTS that the undersigned hereby authorizes,
designates, and appoints Donald McAleenan and Jeffrey A. Wier as such person's
true and lawful attorneys-in-fact and agents, with full power of substitution
and resubstitution and full power to act, for the undersigned and in the
undersigned's name, place, and stead, to execute, acknowledge, deliver, and file
any and all statements required to be filed with the United States Securities
and Exchange Commission (the "Commission") by the undersigned pursuant to 1)
Section 16 of the Securities Exchange Act of 1934, as amended (the "1934 Act")
or 2) Rule 144 promulgated under the Securities Act of 1933, as amended (the
"1933 Act"), and the rules and regulations thereunder with respect to securities
of Builders FirstSource, Inc., a Delaware corporation, including, without
limitation, statements on Form ID, Form 3, Form 4, Form 5 and Form 144 (and any
amendments thereto) and any successor forms adopted by the Commission, as
required by the 1934 Act or the 1933 Act and the rules and regulations
thereunder, and to take such other actions as such attorneys-in-fact may deem
necessary or appropriate in connection with such statements.

This power of attorney shall continue in effect until the undersigned no longer
has an obligation to file statements under Section 16 of the 1934 Act or Rule
144 under the 1933 Act, or until specifically terminated in writing by the
undersigned.  The undersigned acknowledges that the aforesaid persons are not
assuming any of the undersigned's responsibilities to comply with Section 16 of
the 1934 Act or Rule 144 under the 1933 Act.

IN WITNESS WHEREOF, the undersigned has duly executed this power of attorney on
the 26th day of November, 2018.

By:		/s/ David E. Rush
		David E. Rush