Ownership Submission
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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(Print or Type Responses)
1. Name and Address of Reporting Person *
Cline James 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
__X__ Officer (give title below) _____ Other (specify below)
President and CEO
(Last)
(First)
(Middle)
C/O TREX COMPANY, INC., 160 EXETER DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
02/13/2019
(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 02/13/2019   A(1)   16,289 A $ 77.7 79,458 D  
Common Stock 02/13/2019   F(2)   14,944 D $ 77.7 64,514 D  
Common Stock 02/13/2019   A(3)   6,757 A $ 77.7 71,271 D  
Common Stock 02/13/2019   A(4)   9,653 A $ 77.7 80,924 D  
Common Stock 02/14/2019   F(5)   968 D $ 78.34 79,956 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 $ 77.7 02/13/2019   A(6)   7,612   02/13/2019 02/13/2029 Common Stock 7,612 $ 77.7 0 D  

Reporting Owners

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

Signatures

 /s/ William R. Gupp by power of attorney   02/15/2019
**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).
(1) Represents net share difference between target performance-based shares and actual vested shares, based upon actual performance for the Company.
(2) 14,944 shares are being surrendered as allowed by the Company's 2014 Stock Incentive Plan to cover payment of taxes currently due on previously granted restricted shares.
(3) This restricted stock unit vests over a three-year period in three equal annual installments beginning on the first anniversary of the grant date.
(4) This restricted stock unit award is performance-based, and vests over a three-year period in three equal installments beginning on the first anniversary of the grant date. The number of shares set forth above is the target number of shares. The number of shares that will actually vest each year will be based upon performance against certain financial goals for the Company, and will range from 0% to 200% of the target number of shares.
(5) 968 shares are being surrendered as allowed by the Company's 2014 Stock Incentive Plan to cover payment of taxes currently due on previously granted restricted stock units.
(6) This stock appreciation right becomes exercisable in three equal annual installments beginning on the first anniversary of the grant date.
 
Remarks:
1. Represents net share difference between target performance-based shares and actual vested shares, based upon actual performance for the Company.
2. 15,363 shares are being surrendered as allowed by the Company's 2014 Stock Incentive Plan to cover payment of taxes currently due on previously granted restricted shares.
3. This restricted stock unit vests over a three-year period in three equal annual installments beginning on the first anniversary of the grant date.
4. This restricted stock unit award is performance-based, and vests over a three-year period in three equal installments beginning on the first anniversary of the grant date.  The number of shares set forth above is the target number of shares.  The number of shares that will actually vest each year will be based upon performance against certain financial goals for the Company, and will range from 0% to 200% of target number of shares.
5. This stock appreciation right becomes exercisable in three equal installments beginning on the first anniversary of the grant date.

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