TREX CO INC — Director's Dealing 2015

May 14, 2015

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TREX CO INC (TREX)
CIK: 0001069878
Period of Report: 2015-05-12

Reporting Person: Zambanini Adam Dante (Vice President, Marketing)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2015-05-12	Common Stock	M	2438	$12.685	Acquired	26665	Direct
2015-05-12	Common Stock	M	3708	$13.10	Acquired	30373	Direct
2015-05-12	Common Stock	D	1617	$49.1599	Disposed	28756	Direct
2015-05-12	Common Stock	F	1500	$49.1599	Disposed	27256	Direct
2015-05-13	Common Stock	S	3029	$48.8242	Disposed	24227	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2015-05-12	Stock Appreciation Right	$12.685	M	2438	Disposed	2017-02-21	Common Stock (2438)	Direct
2015-05-12	Stock Appreciation Right	$13.10	M	3708	Disposed	2022-02-16	Common Stock (3708)	Direct

Footnotes

F1: Stock Appreciation Rights are being exercised pursuant to a Rule 10b5-1 sales plan adopted by the reporting person on August 11, 2014.

F2: 1,500 shares are being surrendered as allowed by the Company's 2005 Stock Incentive Plan to cover the payment of taxes currently due on the exercise of SARs.

F3: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 sales plan adopted by the reporting person on August 11, 2014.

F4: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $48.39 to $49.25, inclusive. The reporting person undertakes to provide Trex Company, Inc., any security holder of Trex Company, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in Footnote (4) to this Form 4.