Verify Subcontractor Clearance Certificates in Canada

Before paying a construction subcontractor in Canada, a principal should verify the subcontractor's current workers' compensation clearance with the provincial board that governs the work and the payment being released. A valid clearance helps protect the principal from liability for unpaid premiums, but the name and administrative rules change by province: Ontario uses WSIB clearance certificates, Quebec uses CNESST conformity documents, and BC and Alberta use clearance letters.

That is the practical answer if you need to verify clearance certificate before paying subcontractor invoices. Treat the clearance as a payment-release control, especially for final payment. It is evidence that the subcontractor is registered and in good standing with the relevant workers' compensation board at the point you are releasing money.

The underlying risk is liability flow-through. In construction, a principal, general contractor, prime contractor, or trade contractor that hires another business can be exposed when that subcontractor has unpaid workers' compensation premiums or is not in good standing. The clearance instrument is the board's way of saying the payer has verified the status for the relevant period or payment point.

The exact workflow is provincial. An Ontario WSIB clearance has a different cadence from a WorkSafeBC letter addressed to a specific prime contractor. Quebec's CNESST process uses French terms an English-speaking AP team still has to recognize. Alberta's clearance letter guidance is explicit about payment release and final payment.

Clearance is also not the same control as construction holdback, prompt-payment timing, GST/HST registration validation, T5018 reporting, or subcontractor certificate-of-insurance tracking. Those controls may all sit in the same payment file, but they answer different questions. Workers' compensation clearance answers one narrow question: should AP release this subcontractor payment without creating premium-liability exposure for the principal?

Use this as an AP-control framework. Before holding or releasing payment in a disputed case, check the current provincial board guidance and get controller or legal review.

The liability logic is similar across Canada, but the evidence is provincial

Across Canada, workers' compensation boards use different statutes, portals, and document names, but the AP problem is consistent. A business that hires another business for construction work needs evidence that the hired business is properly covered and current with its board obligations before money is released.

"Principal" is the word many boards use for the payer or hiring party. In a construction chain, a general contractor can be the principal to a mechanical contractor, and that mechanical contractor can become the principal to a sheet-metal sub-trade it hires for part of the work. The payment relationship creates the control point: the party paying the invoice needs to know whether the party being paid is in good standing.

Good standing is not a vague comfort phrase. It usually points to the board's view that the contractor has an open account where required, has reported required information, and is current on amounts owing. If the subcontractor is not current, the risk is not just that the invoice file is incomplete. The payer can face exposure for unpaid premiums or board-assessed amounts connected with the contractor's account or the labour portion of the contract, depending on the province.

That is why a pan-Canadian AP procedure cannot rely on one generic certificate template. A mechanical contractor working on a multi-residential project in Ottawa may need a WSIB clearance for Ontario sub-trades, while the same finance team handling a Gatineau package needs to understand CNESST conformity language. A BC job may turn on whether the WorkSafeBC letter is addressed to the right prime contractor. An Alberta job may require a fresh clearance before each payment release.

The board evidence is the source of record. A subcontractor email saying "we are covered" is not the same as a clearance number, clearance letter, or CNESST status that AP can verify and store with the invoice.

Ontario WSIB clearances: 90-day cadence and construction obligations

For Ontario construction work, WSIB treats clearance as an active obligation, not a document to collect once and forget. The WSIB clearance FAQ says construction clearances must be in place before the work begins and for the duration of the work, and a contractor that hires a subcontractor becomes the principal for that subcontracted work.

The AP implication is straightforward: verify the clearance before the first payment, then refresh it whenever the validity window no longer covers the payment being released. WSIB says clearances are valid for up to 90 days from the date of issue and most expire on the 20th of February, May, August, and November. A clearance that supported a February progress draw may not support a June final release.

Ontario also differs from provinces that require a letter addressed to the payer. WSIB says it no longer includes principal information on clearances, so AP should not reject an Ontario certificate merely because the principal's name is absent. The control is to verify the clearance number or contractor status through WSIB and keep the evidence with the subcontractor invoice.

For each Ontario payment file, capture the subcontractor's legal name, WSIB account or clearance number, issue date, expiry date, project, invoice number, payment stage, and reviewer sign-off. If the contractor appears ineligible, do not treat that as an administrative typo. WSIB says contractors marked ineligible cannot be issued a clearance because their account is not up to date; the subcontractor has to cure the account status before AP can rely on a clearance.

The safest internal rule is date-based: no Ontario construction payment is released against a WSIB clearance that has expired before the payment date.

Quebec CNESST: validation, suivi, and attestation terms AP must recognize

Quebec clearance work is harder for many English-speaking AP teams because the official evidence is French and the workflow uses CNESST services de verification de conformite terminology. The payer is the donneur d'ouvrage, meaning the principal or party awarding the work. The subcontractor is the business whose CNESST conformity status has to be checked.

The key terms are worth keeping in the AP procedure because they are the terms staff will see in the portal or on the document:

• Validation de conformité: the conformity validation step before the contract.
• Suivi de l'état de conformité: the follow-up on conformity status during the contract.
• Attestation de conformité: the conformity certificate at the end of the contract.

One timing detail matters for AP: when the donneur d'ouvrage requests a Suivi de l'état de conformité during the contract or an Attestation de conformité at the end, the contractor has 14 days to approve the contract details or object. For payment control, that means the project team should not wait until the cheque run to ask for Quebec evidence. If the final invoice is due this week and the subcontractor has not started the CNESST conformity step, AP may be forced into an avoidable hold.

Keep the French evidence with the invoice file rather than translating it loosely into an email note. The payment file should show the contractor's legal name, the project or contract, the relevant CNESST document or status, the date reviewed, and the staff member who reviewed it. For teams that receive both French invoices and French CNESST evidence, a separate Quebec French supplier invoice workflow for Anglo-Canadian AP can help standardize how names, tax fields, document labels, and supporting evidence are handled.

Do not accept a stale attestation, a screenshot with no contractor identity, or a subcontractor's informal assurance as a substitute for the CNESST status the payment file is meant to preserve.

BC and Alberta clearance letters must be addressed to the right principal

BC and Alberta are where a generic clearance-file habit can break down. In both provinces, AP should pay close attention to who the letter protects, not only whether the subcontractor looks current.

WorkSafeBC's practical rule is that the clearance letter should be addressed to the prime contractor or principal that wants the protection. WorkSafeBC clearance letter guidance says the letter must be addressed to the payer and confirm the subcontractor was active and in good standing for the contract period. If the letter is not addressed to the payer relying on it, AP should treat that as an exception until WorkSafeBC guidance or the board portal confirms the payer is protected.

WCB Alberta clearance help is even more direct about payment. It describes a clearance as a letter confirming the contractor's account is in good standing and clearing a third party from liability for that contractor's premiums. It also says a clearance should be obtained before releasing payments to the company, and that a clearance authorizes final payment on a contract.

For Alberta, labour clearance is the default letter type for hiring contractors or subcontractors. The letter is not a reusable certificate for every customer in the subcontractor's folder. WCB Alberta says letters must be addressed to an individual or company because they clear that specific party from liability, and a separate letter is needed for each principal.

The operational rule is simple enough to enforce in AP: for BC and Alberta, check the subcontractor's status, the payment date, and the addressee. If the letter is stale, missing, or addressed to another company, the invoice remains on hold until the correct clearance evidence is obtained.

Smaller provinces still need a board-specific clearance check

The four largest provincial workflows cover much of the search demand, but they are not the whole Canadian payment-control problem. Saskatchewan, Manitoba, New Brunswick, Nova Scotia, Newfoundland and Labrador, Prince Edward Island, Yukon, Northwest Territories, and Nunavut each have their own workers' compensation board or commission, and each uses its own clearance terminology and portal process.

The underlying payment rule still holds. Saskatchewan WCB clearance letter guidance says principals must get a clearance before paying contractors, and that a clearance releases the principal from having to pay amounts not paid on the contractor's account. Saskatchewan's public guidance also uses practical status outcomes such as cleared, hold, demand, and pending, which are exactly the kinds of statuses AP staff need to record rather than paraphrase.

WCB Manitoba clearance guidance points in the same operational direction for construction firms: get clearance before work starts and before payment is made. For Atlantic and northern jurisdictions, the best article-level guidance is pointer-level by design: check WorkSafeNB, WCB Nova Scotia, WorkplaceNL, WCB PEI, the Yukon Workers' Safety and Compensation Board, and WSCC for Northwest Territories and Nunavut. If the board gives a portal status, a letter, and a PDF download, keep the most specific evidence that ties the subcontractor, principal, contract, and payment date together. Use the live board page or portal for the province or territory connected to the work, and keep that evidence with the invoice file.

Cross-border subcontractors need extra care. A contractor with a home office in one province may be doing covered work in another, or may need out-of-province coverage recognition. AP should not infer that a clearance from the contractor's home board automatically covers a job in another jurisdiction. When the work, payroll, and project site cross provincial borders, the payment file should show which board evidence was checked and why it matched the payment being released.

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Build the clearance check into the subcontractor invoice file

Clearance verification works best when it is part of the subcontractor invoice file, not a separate inbox chase. The file should let a controller, project manager, or auditor see why payment was released on that date.

At minimum, capture these fields:

• Subcontractor legal name
• Province or board checked
• Board account number, clearance number, letter reference, or CNESST document reference
• Project name or number
• Invoice number
• Payment stage, such as first draw, progress draw, or final payment
• Issue date and expiry date, or the board's current validity status
• Addressee or addressed-to-principal detail where required
• Reviewer name and review date
• Exception notes if the status was denied, hold, demand, ineligible, expired, or unclear

The timing should match both the province and the payment stage. Pull evidence before first payment or before work starts where the provincial rule requires it. Refresh it when a validity window expires. Check again before final payment, even if the subcontractor has been paid several times on the same project.

This sits beside, not inside, the other construction AP controls. Canadian construction holdback requirements deal with lien-act or construction-act retention. The T5018 subcontractor payment reporting workflow is the CRA reporting layer for contract payments. PO matching is another operational control, especially for trade invoices where material, labour, and project references need to line up; the HVAC supplier invoice PO matching workflow is a useful comparison for that kind of construction AP file discipline.

Invoice Data Extraction fits this workflow when AP needs structured payment-review data from invoices and supporting documents. Teams can upload subcontractor invoices and related documents, prompt for fields such as vendor legal name, invoice number, project reference, payment stage, board reference, expiry date, and reviewer notes, then download the result as Excel, CSV, or JSON. The product also keeps source file and page references with extracted rows, which helps AP cross-check the spreadsheet against the original documents. It does not validate board status or approve payment on its own; it supports the invoice extraction workflow for construction AP by keeping the invoice and evidence data organized for human review.

If clearance fails, hold the payment and make the exception visible

A failed clearance check is not a formatting problem. It is a payment exception. Common failures include no clearance, an expired clearance, the wrong subcontractor legal name, the wrong province, a letter addressed to another principal, an ineligible or denied account, a hold or demand status, or a vague email from the subcontractor with no board evidence attached.

The first response should be consistent: pause payment release, record the reason in the invoice file, and ask the subcontractor for the correct board evidence or for confirmation that the account status has been cured. If a board portal shows hold, demand, denied, or ineligible status, keep the status wording in the file rather than reducing it to "problem with clearance."

Escalate the exception when the payment is a final release, the draw is large, the board has issued a demand or hold instruction, the subcontractor is working across provinces, or the project team wants to override AP's hold. The approver should be a controller, owner, or other person with authority to weigh legal and commercial risk, not the clerk who happened to find the missing letter.

Some boards give specific guidance on holding back payment or contacting the board when clearance is denied. Follow the board instruction or get legal review before inventing a set-off amount. A principal that guesses at the amount may still end up with an incomplete payment file and an unresolved contractor dispute.

The standard should be blunt enough that staff can apply it under pressure: if the clearance evidence is generic, stale, wrongly addressed, denied, or not tied to the subcontractor being paid, it is not "close enough" for release.