Quanex Building Products Corporation
Power of Attorney

The undersigned hereby constitutes and appoints Paul B. Cornett,
Kevin P. Delaney, Brent L. Korb
and Jairaj T. Chetnani his true and
lawful attorneys-in-fact and agents,
with full power of substitution and re-substitution,
for him and in his name,
place and stead, in any and all capacities,
to complete and sign all Form 3s,
Form 4s and Form 5s relating to equity securities of
Quanex Building Products Corporation and to file the same,
with all exhibits thereto or documents in connection therewith,
with the Securities and Exchange Commission,
the New York Stock Exchange and Quanex Building Products Corporation,
granting to said attorney-in-fact and agent,
full power and authority to do and
perform each and every act and thing requisite and
necessary to be done in and about the premises,
as fully to all intents and purposes as he might or could do in person,
hereby ratifying and confirming all that said attorney-in-fact and agent,
or substitute or substitutes, may lawfully do or
cause to be done by virtue hereof.

Executed this 15th day of November, 2011.


/s/ Robert R. Buck
Robert R. Buck