EXHIBIT 10.4

JOINDER AGREEMENT
Reference is made to the Credit Agreement, dated as of August 23, 2016 (as
amended, amended and restated, supplemented, waived or otherwise modified from
time to time, the “Credit Agreement”) among Westlake Chemical Corporation, the
other Borrowers referred to therein, the Guarantors referred to therein, the
Lenders party thereto and JPMorgan Chase Bank, N.A., as Administrative Agent.
Terms defined in the Credit Agreement are used herein with the same meanings.
NOW, THEREFORE, the Administrative Agent and Westlake Compounds LLC, a Delaware
limited liability company (the “New Guarantor”), in its capacity as a Guarantor,
hereby agree as follows:
1. Joinder as Guarantor. In accordance with Section 5.10(a) of the Credit
Agreement, the New Guarantor by its signature below becomes a Guarantor under
the Credit Agreement with the same force and effect as if originally named
therein as a Guarantor, but in any event subject to the same terms, provisions
and limitations set forth in Article XI of the Credit Agreement. The New
Guarantor hereby agrees to all the terms and provisions of the Credit Agreement
applicable to it as a Guarantor. Each reference to a Guarantor in the Credit
Agreement shall be deemed to include the New Guarantor.
2. Representations and Warranties. The New Guarantor represents and warrants
that each of the representations and warranties set forth in the Credit
Agreement and applicable to the undersigned is true in all material respects on
and as of the date hereof, except to the extent any such representation and
warranty (i) expressly relates to an earlier date in which case such
representation and warranty shall be true and correct in all material respects
as of such earlier date or (ii) is qualified by materiality, in which case such
representation and warranty shall be true and correct in all respects.
3. Severability. Any provision of this Joinder Agreement which is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the
remaining provisions hereof, and any such prohibition or unenforceability in any
jurisdiction shall not invalidate or render unenforceable such provision in any
other jurisdiction.
4. Counterparts. This Joinder Agreement may be executed in counterparts, each of
which shall constitute an original. Delivery of an executed signature page to
this Joinder Agreement by facsimile or electronic transmission shall be as
effective as delivery of an original executed counterpart of this Joinder
Agreement.
5. No Waiver. Except as expressly supplemented hereby, the Credit Agreement
shall remain in full force and effect.
6. Notices. All notices, requests and demands to or upon the New Guarantor, the
Administrative Agent or any Lender shall be governed by the terms of Section
9.01 of the Credit Agreement.

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EXHIBIT 10.4

7. Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.
[Signature Pages Follow]

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EXHIBIT 10.4

IN WITNESS WHEREOF, the undersigned have caused this Joinder Agreement to be
duly executed and delivered by their duly authorized officers as of the day and
year first above written.
Guarantor:

WESTLAKE COMPOUNDS LLC

By:     Axiall Holdco, Inc.
    its Manager
By: /s/ ALBERT CHAO
Name:    Albert Chao
Title:    President

Administrative Agent:

JPMORGAN CHASE BANK, N.A.

By:     /s/ LAURIE C. TUZO
Authorized Signatory
Laurie C. Tuzo
Managing Director

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