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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 IjAdYS2rOoqh7qeqKpHY/byn4FpTU3qhi3k8vohFymMX7eacUihI8ZQ18N9HrZdR
 FFJ4Zkj8Jfe5INsuHzYiuA==

<SEC-DOCUMENT>0001069878-03-000021.txt : 20030703
<SEC-HEADER>0001069878-03-000021.hdr.sgml : 20030703
<ACCEPTANCE-DATETIME>20030703105048
ACCESSION NUMBER:		0001069878-03-000021
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030701
FILED AS OF DATE:		20030703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ANDREWS WILLIAM F
		CENTRAL INDEX KEY:			0001183938

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14649
		FILM NUMBER:		03774014

	BUSINESS ADDRESS:	
		STREET 1:		1409 MORAN ROAD
		CITY:			FRANKLIN
		STATE:			TX
		ZIP:			37069
		BUSINESS PHONE:		6153700098

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TREX CO INC
		CENTRAL INDEX KEY:			0001069878
		STANDARD INDUSTRIAL CLASSIFICATION:	LUMBER & WOOD PRODUCTS (NO FURNITURE) [2400]
		IRS NUMBER:				541910453
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		20 CAMERON ST
		CITY:			WINCHESTER
		STATE:			VA
		ZIP:			22801
		BUSINESS PHONE:		5406784070

	MAIL ADDRESS:	
		STREET 1:		20 CAMERON ST
		CITY:			WINCHESTER
		STATE:			VA
		ZIP:			22801
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001183938d20030703f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<ownershipDocument><schemaVersion>X0101</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-07-01</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0001069878</issuerCik><issuerName>TREX CO INC</issuerName>        <issuerTradingSymbol>TWP</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001183938</rptOwnerCik><rptOwnerName>ANDREWS WILLIAM F</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>  </rptOwnerStreet1><rptOwnerStreet2>  </rptOwnerStreet2><rptOwnerCity>  </rptOwnerCity><rptOwnerState>  </rptOwnerState><rptOwnerZipCode>  </rptOwnerZipCode></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle></officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><derivativeSecurity><securityTitle><value>Stock Options (Right to buy)</value></securityTitle><conversionOrEx
ercisePrice><value>39.25</value></conversionOrExercisePrice><transactionDate><value>2003-07-01</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>218</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-07-01</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2013-07-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>218</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>218</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>
D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">The options become exercisable in four equal annual installments beginning on the first anniversary of the transaction date.</footnote></footnotes><ownerSignature><signatureName>Lynn E. MacDonald</signatureName><signatureDate>2003-07-03</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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