POWER OF ATTORNEY


KNOW ALL PERSONS BY THESE PRESENTS that the undersigned hereby authorizes,
designates, and appoints Jeffrey A. Wier as such person's true and lawful
attorney-in-fact and agent, 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 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 person is 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 9th day of December, 2005.




                                         By: /s/ Donald F. McAleenan