POWER OF ATTORNEY
Section 16 Filers (Directors and Officers)

Know all by these presents, that the undersigned hereby
constitutes and appoints Joseph M. Nowicki, signing singly,
the undersigned's true and lawful attorney-in-fact to:

(1)	execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer and/or director of
Beacon Roofing Supply, Inc. (the "Company"), Forms 3, 4 and
5 in accordance with Section 16(a) of the Securities
Exchange Act of 1934 and the rules thereunder;

(2)	do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to complete
and execute any such Form 3, 4, or 5, complete and execute
any amendment or amendments thereto, and timely file such
form with the United States Securities and Exchange
Commission and any stock exchange or similar authority; and

(3)	take any other action of any type whatsoever in connection
with the foregoing which, in the opinion of such attorney-
in-fact, may be of benefit to, in the best interest of, or
legally required by, the undersigned, it being understood
that the documents executed by such attorney-in-fact on
behalf of the undersigned pursuant to this Power of Attorney
shall be in such form and shall contain such terms and
conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact
full power and authority to do and perform any and every act
and thing whatsoever requisite, necessary, or proper to be
done in the exercise of any of the rights and powers herein
granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with
full power of substitution or revocation, hereby ratifying
and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully
do or cause to be done by virtue of this power of attorney
and the rights and powers herein granted. The undersigned
acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned,
are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of
the Securities Exchange Act of 1934. This Power of Attorney
shall remain in full force and effect until the undersigned
is no longer required to file Forms 3, 4, and 5 with respect
to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by
the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of
Attorney to be executed as of this 1st day of November, 2018.

/s/ Barbara G Fast