<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-07-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000095301</issuerCik>
        <issuerName>SEQUA CORP /DE/</issuerName>
        <issuerTradingSymbol>SQAB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001015725</rptOwnerCik>
            <rptOwnerName>ALEXANDER NORMAN E/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 PARK AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10166</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Chairman</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common</value>
            </securityTitle>
            <transactionDate>
                <value>2005-07-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>57702</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>57702</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common</value>
            </securityTitle>
            <transactionDate>
                <value>2005-07-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>57702</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class B Common</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1663721</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 3</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class B Common</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>347438</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 4</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Note 1: These shares were transferred from a trust of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries to Mr. Alexander and were, therefore, previously reported as indirectly beneficially owned.</footnote>
        <footnote id="F2">Note 2:  These shares were transferred from Mr. Alexander to a trust of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries and are, therefore, now indirectly beneficially owned.</footnote>
        <footnote id="F3">Note 3:  Indirect ownership by Fifty Broad Street, Inc. (167,878 shares), Forfed Corporation (1,379,843 shares), 42 New Street Inc. (45,000 shares), YOUANDI Corp. (30,000 shares) and Galleon Syndicate Corporation (41,000 shares), all of which are controlled by Mr. Alexander.</footnote>
        <footnote id="F4">Note 4: Shares held in two trusts of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Norman E. Alexander</signatureName>
        <signatureDate>2005-07-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2005-07-13
0
0000095301
SEQUA CORP /DE/
SQAB
0001015725
ALEXANDER NORMAN E/
200 PARK AVENUE
NEW YORK
NY
10166
1
1
1
0
Executive Chairman
Class B Common
2005-07-13
4
J
0
57702
0
A
57702
D
Class B Common
2005-07-13
4
J
0
57702
0
D
0
D
Class B Common
1663721
I
See Note 3
Class B Common
347438
I
See Note 4
Note 1: These shares were transferred from a trust of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries to Mr. Alexander and were, therefore, previously reported as indirectly beneficially owned.
Note 2:  These shares were transferred from Mr. Alexander to a trust of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries and are, therefore, now indirectly beneficially owned.
Note 3:  Indirect ownership by Fifty Broad Street, Inc. (167,878 shares), Forfed Corporation (1,379,843 shares), 42 New Street Inc. (45,000 shares), YOUANDI Corp. (30,000 shares) and Galleon Syndicate Corporation (41,000 shares), all of which are controlled by Mr. Alexander.
Note 4: Shares held in two trusts of which Mr. Alexander, his wife and his estate and/or issue are beneficiaries.
/s/ Norman E. Alexander
2005-07-15