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Registry office · Federal Revenue Service

Building work clearance certificate (CND) from the Federal Revenue Service (CNO and SERO)

Registration of the work in the CNO, assessment in SERO and the Federal Revenue Service certificate, with the right classification and the supporting documents that go into the calculation of the INSS on the work.

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Wooden site table with a folder of building-material invoices, receipts held with a clip, a calculator, a hard hat and the house key, in front of a newly finished two-story house

Quick answer

Building work clearance certificate (CND) from the Federal Revenue Service (CNO and SERO) in São Paulo, in a few lines

The building work clearance certificate (CND) is the Federal Revenue Service certificate showing that the contributions on the labor for a construction, renovation or demolition have been calculated and are up to date. The work is registered in the National Works Registry (CNO), assessed in SERO, which calculates the amount from the area, intended use, category and type of work, and declared in the assessment DCTFWeb. In São Paulo, since Provision CG 17/2026, the São Paulo Inspectorate of Justice rules require the Habite-se or an equivalent City Hall document for the recording, but federal law still mentions the certificate, the debt on the work remains with the Federal Revenue Service and the registry office confirms what it requires in each case. MTC checks the registration and the classification, gathers the supporting documents that go into the calculation and follows the assessment through to the certificate.

Updated on by the MTC technical team, based on the rules cited on this page.

Work registration
CNO within 30 days of the start of the work
Source: Federal Revenue Service: National Works Registry (CNO)(opens in a new tab)
Certificate validity
180 days from issuance
Source: Normative Instruction RFB No. 2.021/2021 (construction works and SERO)(opens in a new tab)
Older work
Periods more than 5 years old are left out of the calculation
Source: Federal Revenue Service: work more than 5 years old (limitation period)(opens in a new tab)
Not regularized
Fines of 75% to 225% if a violation notice is issued
Source: Federal Revenue Service: notice to regularize building work(opens in a new tab)

What the building work clearance certificate (CND) is

The building work clearance certificate (CND) is the Federal Revenue Service certificate showing that the social security contributions on the labor for a construction, expansion, renovation or demolition have been calculated and are up to date. The work is registered in the National Works Registry (CNO) and assessed in SERO, which estimates the labor from the area and type of construction, and the amount is declared in the assessment DCTFWeb. Once the debt is paid or put in installments, the CND or the CPEND is issued; both have the same legal effect.

The Federal Revenue Service requires the CNO within 30 days of the start of the work and tracks works through the permits and Habite-se certificates reported by city halls. Anyone who does not regularize may be audited and have the contributions assessed with fines of 75% to 225%. In São Paulo, Provision CG 17/2026 removed the social security certificate from the requirements for recording, but the debt on the work remains: federal law still mentions the certificate and the Federal Revenue Service can collect within the 5-year limit.

What most often holds things up is the calculation: area classified incorrectly, garage and pool entered as main area, labor not declared in eSocial and invoices nobody kept. On older work, proof of the date is missing. MTC checks the CNO and the classification against the design and the Habite-se, gathers the supporting documents that reduce the calculation and follows the assessment, the payment and the certificate.

What MTC does

  • CNO registration

    Registration or correction of the work, with the right area, category and type.

  • Classification and calculation

    Areas, intended use and reductions checked against the approved design.

  • Supporting documents for the work

    Invoices, declared payroll and proof of dates gathered for SERO.

  • Assessment and certificate

    Assessment DCTFWeb, payment slip and building work clearance certificate.

Understand it in one image

From registering the work to the certificate in hand

  1. 1

    CNO registration

    Work registered within 30 days of the start.

  2. 2

    Habite-se

    City Hall issues the document and informs the Federal Revenue Service.

  3. 3

    Assessment in SERO

    Calculation by area, intended use, category and type.

  4. 4

    DCTFWeb and payment

    Amount declared, paid or in installments.

  5. 5

    Building work clearance certificate

    CND or CPEND, valid for 180 days.

Does the São Paulo registry office still require it? Since 2026, the Inspectorate of Justice rules require the City Hall document; the debt on the work with the Federal Revenue Service remains.

Illustrative diagram, based on Law No. 8.212/1991 (arts. 47, 49 and 50), Normative Instruction RFB No. 2.021/2021 and the Federal Revenue Service's SERO Manual.

The path from the work to the certificate

If one step fails, the certificate is not issued.
  1. 01 · CNOWork registered with the design data
  2. 02 · SEROAssessment by area, intended use and type
  3. 03 · DCTFWebAmount declared, paid or in installments
  4. 04 · CertificateCND or CPEND, valid for 180 days
Most common situations:Habite-se issued, Federal Revenue Service still pendingFederal Revenue Service notice to regularizeOlder work without a certificateProperty bought without the work regularizedRenovation or expansionINSS on the work too high

What goes into the calculation of the INSS on the work

For work by an individual, the Federal Revenue Service does not add up each bricklayer's invoice: it estimates the labor from the area, intended use, category and type of work, and then applies reductions and deductions. This is where the right classification and the supporting documents make a difference.

ItemHow the Federal Revenue Service treats it
Cost of the workArea for calculation multiplied by the VAU for the month of the assessment, a Federal Revenue Service table based on the state capital's CUB (art. 25)
Type of workLabor at 20% of the cost for masonry and 15% for wood or mixed construction; for a low-income house of up to 70 m², 12% and 7%
Complementary areasPool, sports court and ground-level garage outside the main building: 50% reduction if covered and 75% if uncovered
Renovation and demolition65% reduction for renovation and 90% for demolition (art. 26)
IndividualSocial factor from 20% (up to 100 m²) to 90% (over 400 m²), according to the area of each category
Precast elementsPrecast structure or exterior walls: 70% reduction, with invoices for at least 40% of the cost
Ready-mix concrete or mortarDeduction calculated by SERO; the purchase invoices are kept for inspection
Labor already declaredPayroll for the work in eSocial or GFIP, and services from self-employed workers and MEIs linked to the CNO, adjusted by the Selic rate (art. 32)
Work more than 5 years oldOnly the months not yet time-barred count, with proof of the start or end date (arts. 29 and 42)

The reductions apply only to the calculation: the certificate is issued with the assessed area. The classification must match the design and the invoices, which the Federal Revenue Service can request within the 5-year limit.

Source: Normative Instruction RFB No. 2.021/2021 (construction works and SERO)(opens in a new tab)

Why regularize the work with the Federal Revenue Service

From work pending with the Federal Revenue Service to the certificate in hand

Tap a problem to see how it is solved.

What happens when the work is not regularized with the Federal Revenue Service

The debt on the work does not show up day to day or in the IPTU. It appears when the Federal Revenue Service cross-checks the Habite-se, when the notice arrives or when someone asks for the certificate, and each stage weighs more than the one before.

  1. 1

    Work not registered

    The Federal Revenue Service requires the CNO within 30 days of the start of the work.

    What can be done

    Register the work with the data from the approved design.

  2. 2

    Habite-se reported

    City Hall reports permits and Habite-se certificates, and the Federal Revenue Service starts tracking the work.

    What can be done

    Do the assessment right after the Habite-se.

  3. 3

    Notice to regularize

    The Federal Revenue Service sends a notice with a deadline to regularize the work or explain the situation.

    What can be done

    Respond within the deadline, with the assessment or with documents.

  4. 4

    Enforcement

    Once the deadline passes, the contributions can be assessed with fines of 75% to 225%.

    What can be done

    Assess the defense with the client's lawyer or accountant.

Beyond the Federal Revenue Service: where work without a certificate weighs

In a sale

  • Wary buyerThe debt on the work is part of the review.
  • Last-minute rush at the deedThe certificate becomes urgent at the end.

In finances

  • High fine75% to 225% of the assessed amount.
  • Late DARF paymentLate-payment fine and Selic interest.

In the family

  • Inheritance with a pending issueHeirs receive the work still to be regularized.
  • Proof that disappearsInvoices and receipts get lost over time.

Finished the work or received a notice from the Federal Revenue Service? Contact MTC before the charge arrives.

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What regularized work brings

  • Certificate in hand

    The work's CND or CPEND for the registry office.

  • Calculation by the rules

    Amount calculated with the reductions that apply to the work.

  • Lower risk

    Work assessed before the notice turns into a violation notice.

  • CNO closed

    Registration closed once the whole work has been assessed.

  • Smooth sale

    The buyer receives the work in good standing.

  • Inheritance in order

    A property free of the pending work issue for the family.

When it is needed

  • Habite-se or Certificate of Completion issued
  • Federal Revenue Service notice to regularize the work
  • Registry office requirement for the recording
  • Sale, financing or probate of the property
  • Older work never regularized with the Federal Revenue Service
  • Property bought from a builder without the work regularized

Documents that help you get started

You do not need all of them. The team will tell you what is missing.

  • Updated property record
  • Permit, approved design and Habite-se or Certificate of Completion
  • CNO number or former CEI registration number, if any
  • Invoices for services, precast elements and ready-mix concrete
  • Receipts and payroll for the workers on the job
  • gov.br silver or gold account access, or a power of attorney in e-CAC

How we handle your case

  1. 1

    Diagnosis

    Design, Habite-se, CNO and what has already been declared.

  2. 2

    CNO registration

    Registration or correction of the area, category and type.

  3. 3

    Supporting documents

    Invoices, payroll and proof of dates gathered.

  4. 4

    Assessment in SERO

    Calculation checked and assessment DCTFWeb.

  5. Building work clearance certificate

    CND or CPEND ready for the registry office.

Important
  • The amount is calculated by the Federal Revenue Service in SERO, under the rules for building work.
  • Payment after the due date or in installments carries a late-payment fine and Selic interest.
  • In São Paulo, the registry office confirms what it requires for the recording in each case.
  • A company with regular bookkeeping does the assessment with its accountant; MTC takes care of the technical part.

Questions about the building work clearance certificate (CND) from the Federal Revenue Service (CNO and SERO)

The questions that come to the team and show up in searches most often, with the answer and the source.

See all questions

The work must be registered in the CNO and assessed in SERO, which calculates the contributions and generates the assessment DCTFWeb. With the debt paid or in installments and no pending issues, the CND or the CPEND is issued; both have the same legal effect. Only the party responsible for the work can regularize it: the property owner, the owner of the work, the developer or a builder hired under a turnkey contract.

Source: gov.br: issuing the tax clearance certificate for building work (opens in a new tab)

Law 8.212/1991 (art. 47) still mentions the building work clearance certificate for the recording. In São Paulo, Provision CG 17/2026 changed the Inspectorate of Justice rules: the construction is recorded with the Habite-se, the Certificate of Completion or an equivalent City Hall document, and the registrar does not make the registration conditional on settling social security debts. The debt on the work with the Federal Revenue Service remains, and the registry office confirms what it requires in each case.

Source: São Paulo Inspectorate of Justice rules, Chap. XX, items 117.1 and 120.3 (Provision CG 17/2026) (opens in a new tab)

There is no fixed amount per square meter. SERO multiplies the area by the VAU, a monthly Federal Revenue Service table based on the CUB, applies the labor percentage for the type of work and the reductions, and deducts what was already declared during the work. Area, intended use, category and type change the result.

Source: Federal Revenue Service: SERO Manual, version 3.0 (08/2024) (opens in a new tab)

Through the reductions set out in the rules, always with proof: correct classification of the areas, complementary areas such as a pool and a ground-level garage, the social factor for individuals, precast elements, ready-mix concrete and labor declared in eSocial during the work. Each item must match the design and the invoices, which the Federal Revenue Service may request.

Source: Normative Instruction RFB No. 2.021/2021 (construction works and SERO) (opens in a new tab)

The Federal Revenue Service has 5 years, counted from the first day of the following year, to assess the contribution. For work done partly within that period, only the months not yet time-barred go into the calculation. The start or end date may have to be proven with the Habite-se, an IPTU record showing the area, the deed or other documents from that time.

Source: Federal Revenue Service: work more than 5 years old (limitation period) (opens in a new tab)

The buyer can regularize the area of their unit in their own name, with a CNO linked to the registration of the original work, and do the assessment in SERO. The credits the builder or the developer had on the work count in proportion to the unit's area.

Source: Federal Revenue Service: regularization of acquired building work (opens in a new tab)

180 days from issuance. There is no limit on certificates for the same assessment: to extend the validity, or to replace the positive certificate with the effect of a negative one with a negative certificate, a new one is issued.

Source: Normative Instruction RFB No. 2.021/2021 (construction works and SERO) (opens in a new tab)

The Federal Revenue Service tracks works through the permits and Habite-se certificates reported by city halls. If the notice deadline passes without regularization, the work may be audited and the contributions assessed with fines of 75% to 225%. If the work has not started yet or was carried out by someone else, the notice is answered with documents.

Source: Federal Revenue Service: notice to regularize building work (opens in a new tab)

Legal basis and sources

Informational content, reviewed on November 11, 2026. The rules may change; the analysis of each case considers the rule in force on the date of the application. MTC is a private company, not affiliated with government agencies.

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