TREX CO INC — Director's Dealing 2012

May 15, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TREX CO INC (TREX)
CIK: 0001069878
Period of Report: 2012-05-11

Reporting Person: Gupp William R. (CAO, Gen. Counsel & Secretary)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-11	Common Stock	M	6456	$13.44	Acquired	40797	Direct
2012-05-11	Common Stock	F	1516	$30.30	Disposed	39281	Direct
2012-05-11	Common Stock	D	2864	$30.30	Disposed	36417	Direct
2012-05-15	Common Stock	S	200	$30.00	Disposed	36217	Direct
2012-05-15	Common Stock	S	300	$30.03	Disposed	35917	Direct
2012-05-15	Common Stock	S	100	$30.04	Disposed	35817	Direct
2012-05-15	Common Stock	S	100	$30.05	Disposed	35717	Direct
2012-05-15	Common Stock	S	200	$30.12	Disposed	35517	Direct
2012-05-15	Common Stock	S	500	$30.18	Disposed	35017	Direct
2012-05-15	Common Stock	S	100	$30.26	Disposed	34917	Direct
2012-05-15	Common Stock	S	300	$30.27	Disposed	34617	Direct
2012-05-15	Common Stock	S	276	$30.29	Disposed	34341	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-05-11	Stock Appreciation Right	$13.44	M	6456	Disposed	2019-02-18	Common Stock (6456)	Direct

Footnotes

F1: The stock appreciation right becomes exercisable in three equal installments beginning on the first anniversary of the grant date.

F2: 1,516 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 stock appreciation rights.