FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Posey Richard E   2. Issuer Name and Ticker or Trading Symbol TREX CO INC [TREX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O TREX COMPANY, INC., 160 EXETER DRIVE 3. Date of Earliest Transaction (Month/Day/Year) 05/11/2015 (Street) WINCHESTER, VA 22603-8605 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/11/2015   M   812 A $ 10.7 10,772 D   Common Stock 05/11/2015   M   1,206 A $ 8.54 11,978 D   Common Stock 05/11/2015   M   656 A $ 6.53 12,634 D   Common Stock 05/11/2015   M   884 A $ 10.225 13,518 D   Common Stock 05/11/2015   M   990 A $ 10.12 14,508 D   Common Stock 05/11/2015   M   1,052 A $ 7.43 15,560 D   Common Stock 05/11/2015   D   988 D $ 50.86 14,572 D   Common Stock 05/12/2015   S   100 D $ 49.36 14,472 D   Common Stock 05/12/2015   S   300 D $ 49.39 14,172 D   Common Stock 05/12/2015   S   100 D $ 49.4225 14,072 D   Common Stock 05/12/2015   S   500 D $ 49.43 13,572 D   Common Stock 05/12/2015   S   300 D $ 49.44 13,272 D   Common Stock 05/12/2015   S   200 D $ 49.52 13,072 D   Common Stock 05/12/2015   S   200 D $ 49.5325 12,872 D   Common Stock 05/12/2015   S   400 D $ 49.72 12,472 D   Common Stock 05/12/2015   S   200 D $ 49.76 12,272 D   Common Stock 05/12/2015   S   100 D $ 49.88 12,172 D   Common Stock 05/12/2015   S   300 D $ 49.89 11,872 D   Common Stock 05/12/2015   S   300 D $ 49.99 11,572 D   Common Stock 05/12/2015   S   300 D $ 50.0301 11,272 D   Common Stock 05/12/2015   S   200 D $ 50.29 11,072 D   Common Stock 05/12/2015   S   300 D $ 50.3 10,772 D   Common Stock 05/12/2015   S   100 D $ 50.31 10,672 D   Common Stock 05/12/2015   S   100 D $ 50.315 10,572 D   Common Stock 05/12/2015   S   612 D $ 50.41 9,960 D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Stock Appreciation Right

$ 10.7

05/11/2015

M

812

04/01/2010

04/01/2020

Common Stock

812

$ 0

0

D

Stock Appreciation Right

$ 8.54

05/11/2015

M

1,206

10/01/2009

10/01/2019

Common Stock

1,206

$ 0

0

D

Stock Appreciation Right

$ 6.53

05/11/2015

M

656

07/01/2009

07/01/2019

Common Stock

656

$ 0

0

D

Stock Appreciation Right

$ 10.225

05/11/2015

M

884

07/01/2010

07/01/2020

Common Stock

884

$ 0

0

D

Stock Appreciation Right

$ 10.12

05/11/2015

M

990

01/04/2010

01/04/2020

Common Stock

990

$ 0

0

D

Stock Appreciation Right

$ 7.43

05/11/2015

M

1,052

07/21/2009

07/21/2019

Common Stock

1,052

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Posey Richard E C/O TREX COMPANY, INC. 160 EXETER DRIVE WINCHESTER, VA 22603-8605	X

Signatures

/s/ William R. Gupp by power of attorney		05/13/2015
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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