Do I Have to Pay a Contractor for Poor Work in Canada? (2026 Guide)

Searches about paying a contractor for poor work in Canada spike whenever an owner, general contractor or subcontractor discovers defective workmanship on site and asks a deceptively simple question: do I actually have to pay? The short answer is that you often can withhold, reduce or recover money for defective work, but the lawful route depends on your contract, the applicable provincial holdback and lien rules, and, in Ontario, the prompt payment and adjudication provisions of the Construction Act.

In 2026, the maturing adjudication regime and continued refinement of Ontario’s Construction Act have made the mechanics of withholding, backcharging and disputing payment more procedural than ever, which means the difference between a defensible deduction and a repudiatory breach frequently comes down to notices, timing and evidence. This guide walks owners, GCs, subcontractors and project managers through the decision flow step by step.

Quick decision flow, can you lawfully withhold payment?

When defective work appears, resist the instinct to simply stop paying. A unilateral refusal to pay, applied without contractual or statutory basis, can convert your legitimate defect complaint into your own breach of contract. Instead, work through a structured decision flow that identifies which remedy fits the situation and preserves your position for later dispute resolution.

• Pay in full. If the work is compliant or the variance is within tolerable specification, the invoice is generally payable. Overstating a minor cosmetic issue as a “defect” is a common and costly mistake.
• Partial pay. Where most of the work is sound but a discrete element is deficient, pay the undisputed portion and address only the disputed amount through the proper notice mechanism.
• Withhold. Where the contract or statute permits a holdback or deduction, withhold a proportionate, quantified amount tied to the specific deficiency and served with the required notice.
• Backcharge. Where you have incurred (or will incur) quantifiable remedial costs and the counterparty is liable, deduct that cost against amounts owing and document the accounting.
• Start adjudication. In Ontario, where a payment dispute cannot be resolved and cash flow matters, an interim binding adjudication decision may be the fastest route.

The core principle: every step above must be documented and, where required, preceded by written notice. Whether you must pay for defective work turns less on the existence of a defect and more on whether you followed the correct process to challenge it.

Key immediate actions, serve notice, document defects, preserve evidence

Before any deduction, take three immediate steps. First, inspect and photograph the defective work in place, with date stamps and reference to drawings or specifications. Second, quantify the reasonable cost to remedy, ideally with a third-party estimate. Third, serve written notice on the contractor identifying the deficiency, the contractual or specification requirement breached, and the amount in dispute. In Ontario’s prompt payment environment, the timing and content of that notice are not optional formalities, they are what makes a withholding lawful. Preserve all correspondence, site records, inspection reports and change orders, because these become the evidentiary spine of any subsequent adjudication, lien claim or court action.

Contract vs statute, reading your contract and the applicable provincial rules

Two legal frameworks govern whether you can withhold money for poor work: your contract and the applicable provincial statute. They interact, and neither can be ignored. The contract sets out payment schedules, retainage, defect obligations and notice mechanics. The provincial construction or builders’ lien legislation imposes mandatory holdback and lien regimes, and, in Ontario, prompt payment and adjudication rules that override or supplement contractual freedom. A deduction that is valid under your contract can still be unlawful if it breaches statutory holdback or prompt payment obligations, and vice versa.

The critical limitation to understand is that you cannot simply invent a deduction. Unilateral set-offs applied without a contractual right or statutory basis expose the withholding party to interest claims, adjudication liability and, in extreme cases, a finding of repudiation. Read the payment clause, the holdback clause, the defects/warranty clause and the notice clause together before acting.

Common contract clauses that matter

• Payment and progress draw clauses. These define when payment becomes due and what certification (architect or engineer sign-off) is required. Withholding before payment is even due is usually premature.
• Holdback and retainage clauses. Contractual retention (distinct from the statutory holdback) may permit retaining a percentage pending completion or correction of deficiencies.
• Defects and rectification clauses. These typically give the contractor an opportunity to remedy before the owner engages others and backcharges the cost. Skipping the contractor’s cure right can undermine a backcharge.
• Notice clauses. Many contracts require written notice within a defined period. Failure to give timely notice can waive the right to deduct.

Provincial differences at a glance (Ontario priority)

Ontario’s regime under the Construction Act is among the most developed prompt payment and adjudication frameworks in the country, and it is the focus of this guide. Other provinces have their own construction or builders’ lien statutes with distinct holdback percentages, notice periods and, increasingly, their own prompt payment and adjudication schemes at various stages of implementation. British Columbia, Alberta, Saskatchewan and Quebec each operate under separate legislation with different mechanics and terminology. If your project is outside Ontario, treat the Ontario-specific procedural detail below as illustrative only and obtain local counsel to confirm the exact statutory requirements, holdback amounts and limitation periods in your jurisdiction. The strategic logic of documenting defects and serving notice, however, holds everywhere.

Can I withhold payment for poor work in Canada? Deficiency holdbacks and notices of non-payment

The most common way owners and contractors respond to defective work is to withhold payment, but withholding lawfully requires more than dissatisfaction. In Ontario, the prompt payment regime under the Construction Act ties payment to a chain of proper invoices and notices, and the mechanism for disputing an amount is a written notice of non-payment. Getting the substance and timing of that notice right is what separates a defensible position from an actionable breach.

Work through these steps before withholding for a decision on whether to pay for defective work:

1. Inspect and confirm the defect. Establish that the work fails to meet the contract specification, applicable code or the standard of a competent tradesperson, not merely your preference.
2. Document thoroughly. Capture photographs, video, test results and references to the relevant drawings and specifications.
3. Quantify the cost to remedy. Obtain a written estimate for the corrective work so any withholding is proportionate and defensible.
4. Serve a written notice of non-payment. Identify the invoice, the amount disputed, and the reason, within the timeframe the prompt payment regime and your contract require.
5. Preserve lien and adjudication timelines. Note the deadlines for the counterparty to respond, to lien and to commence adjudication, so you are not caught out procedurally.

Sample “Notice of Non-Payment / Deficiency”, required elements

A defensible notice of non-payment in Ontario should be in writing and should, at a minimum, contain the following elements. Note that the Construction Act and its regulation prescribe forms for certain notices of non-payment, so check the current prescribed form and content requirements. Use plain, specific language:

• Identification of the parties and project, contract reference, project address and the invoice or payment application in dispute.
• The amount being paid and the amount withheld, stated clearly and separately, so the undisputed portion is not held up.
• The reason for non-payment, a specific description of the defective work, the contractual or specification requirement breached, and the location.
• The basis of quantification, reference to the estimated cost to remedy or the contractual holdback relied upon.
• The date and signature, with service in the manner the contract and statute require.

A generic “we are not satisfied” letter is not a notice of non-payment. The document must engage with the specific deficiency and the specific amount, because an adjudicator or court will scrutinise whether the withholding was properly justified at the time it was made.

When a unilateral deduction becomes a repudiatory breach

There is a line between a lawful, proportionate deduction and conduct that repudiates the contract. Withholding an amount grossly disproportionate to the defect, refusing to pay clearly undisputed sums, or ignoring the contractor’s contractual right to cure can all support an argument that the paying party, not the contractor, is in breach. Repudiation can open the door to the contractor terminating, claiming lost profit and pursuing interest and costs. The safeguard is proportionality and process: withhold only what is genuinely referable to the defect, pay everything else, and paper the reasoning.

Backcharges, when to pursue, proof required, accounting and offsets

A backcharge is the deduction of the cost of remedying defective work (or completing incomplete work) from amounts otherwise owing to the responsible party. It differs from a simple holdback because it represents an actual quantified recovery of remedial cost rather than mere retention pending correction. Backcharges are a powerful tool in disputes over defective work, but they are also the most fact-intensive to prove, and poorly supported backcharges are routinely reversed in adjudication and litigation.

Entitlement to a backcharge generally requires three things: that the counterparty was contractually or legally liable for the defect or omission; that the counterparty was given the opportunity to remedy where the contract requires it; and that the cost claimed is reasonable and actually incurred or reliably estimated. Where the contract contains a rectification clause giving the contractor a cure period, unilaterally engaging a replacement trade and backcharging without first offering that opportunity is a frequent basis for challenge.

On the accounting side, a backcharge must be transparent. Issue a backcharge document or notice that itemises the corrective work, the labour and material costs, any supervision or overhead claimed, and the invoices or receipts supporting each line. Apply the backcharge against the correct payment application and keep the calculation auditable. Vague, lump-sum backcharges without supporting documents rarely survive scrutiny.

Evidence checklist for a successful backcharge

• Photographs and video of the defective condition before and after remediation.
• Test reports and inspection records demonstrating non-compliance with code or specification.
• Change orders and instructions showing scope and any variations relevant to the defect.
• Repair estimates and paid invoices from the remedial contractor.
• Correspondence evidencing notice to the responsible party and any offer to cure.
• Expert reports where the cause of the defect or the reasonableness of the remedy is contested.

Adjudication and prompt payment, Ontario (2026) and practical strategy

Ontario’s Construction Act introduced a prompt payment regime and a statutory adjudication process designed to keep money flowing through the construction pyramid while disputes are resolved. For anyone deciding whether to pay for defective work in Ontario, adjudication is now central: it provides a fast, interim binding decision that preserves cash flow and forces early resolution rather than allowing disputes to fester until final litigation. The statutory framework, including the prompt payment timelines and the adjudication procedure, is set out in the Construction Act, with adjudication administered under the authority designated by the Act.

In broad terms, the regime works on a chain of proper invoices: once a payer receives a proper invoice, payment obligations and the window to dispute (by delivering a notice of non-payment) are triggered and cascade down the contractual chain. If a payment dispute arises, including a dispute over withholding for defective work, a party may refer the matter to adjudication. The adjudicator issues a decision that is binding on an interim basis, meaning the parties must comply, but either party can later pursue the matter through arbitration or the courts for a final determination.

The Canadian College of Construction Lawyers publishes practitioner commentary and legal updates tracking how these provisions are developing in practice; see the Canadian College of Construction Lawyers and the Canadian Bar Association for current professional analysis.

A practical note on the interim nature of adjudication: because the decision is provisional, a party who prevails must still be prepared to defend the outcome if the loser later commences litigation. Nonetheless, in many disputes the interim decision becomes the de facto resolution, because the cost and delay of relitigating rarely justifies it. That reality makes the quality of the evidence you put before the adjudicator decisive.

Fast strategy: when to go to adjudication vs. negotiate

Adjudication is best suited to disputes where a quick, enforceable interim decision protects cash flow and where the facts and quantum are reasonably clear. It can be less attractive where the dispute turns on complex, contested expert evidence about the cause of a defect, because the compressed timetable limits the depth of expert analysis an adjudicator can absorb. Negotiation or mediation remains preferable where the commercial relationship is ongoing and worth preserving, or where the amount in dispute is modest relative to the cost of the process. A pragmatic sequence is to serve a well-drafted notice, attempt commercial resolution promptly, and use the credible option of adjudication to concentrate minds.

What evidence an adjudicator expects

Adjudicators work quickly and rely heavily on the documentary record. Expect to provide the contract and any relevant schedules, the disputed invoices and payment applications, the notice of non-payment, dated photographs of the defective work, test and inspection reports, remedial estimates and invoices, and, where causation or reasonableness is disputed, a concise expert report. Because the timetable is short, the party who arrives with a well-organised, indexed bundle that ties each defect to a contractual requirement and a quantified cost is far more persuasive than one relying on assertion. This is why disciplined documentation from the first day a defect appears pays dividends.

Withhold payment vs backcharge vs adjudication, which route?

The table below summarises the three principal routes for responding to defective work, when each fits, and the evidence each demands. Most real disputes involve a combination, for example, withholding under a notice of non-payment, then referring the dispute to adjudication if it is not resolved.

Liens, claims, limitation periods and warranty remedies

Defective work rarely lives in isolation from lien rights and limitation periods, and these frameworks shape your leverage in a dispute over paying for poor work. A construction lien is a statutory security against the improved property that secures amounts owing for work or materials. Where a contractor claims payment you have withheld for defects, that contractor may register a lien, and the existence and validity of the defects becomes a live issue in the lien proceeding. Conversely, an owner’s genuine, quantified deficiency claim can reduce or extinguish the amount properly secured by a lien.

Strict statutory deadlines govern when a lien must be preserved and perfected, and missing these deadlines can extinguish otherwise valid claims. Separate limitation periods govern claims for defective work and breach of warranty, and these are subject to the general limitations legislation of the relevant province together with any contractual warranty terms. Latent defects, those not reasonably discoverable at completion, can affect when time begins to run because a limitation period may run from discovery rather than completion, but the analysis is fact-specific and jurisdiction-specific. Do not assume a defect discovered years later is still actionable, and do not assume it is time-barred; confirm the applicable limitation period against the governing statute and contract.

Interaction between lien rights and adjudication / enforcement

Adjudication and lien rights operate in parallel, not as alternatives. A party can pursue adjudication to obtain a fast interim decision on payment while also preserving lien rights within the statutory timeframe. An adjudicator’s decision, once rendered, is binding on an interim basis and can be enforced through the court process where a party fails to comply. Because the two regimes have different deadlines and different consequences, the safest course is to calendar every lien, notice and adjudication deadline the moment a defect dispute arises, so that pursuing one remedy never inadvertently forfeits another.

When to involve lawyers, tactical triggers

Not every deficiency needs a lawyer, but several triggers should prompt you to instruct construction counsel early: the disputed amount is material to the project or your business; the contractor has threatened or registered a lien; a notice of non-payment has been served or received and a prompt payment deadline is running; the defect involves structural, safety or code issues; or adjudication or litigation is contemplated by either side. Early advice is almost always cheaper than remedial advice after a misstep, because the quality of your notices and documentation in the first days often determines the outcome.

When you meet counsel, bring the contract and all schedules, dated photographs and inspection reports, the full payment and invoicing record, all correspondence with the counterparty, any remedial estimates or invoices, and a chronology of events. For deeper reading, see the Global Law Experts Construction practice, Canada page and its practice notes on construction adjudication, prompt payment, and construction liens and holdbacks in Canada. To discuss a specific dispute, see Brendan D. Bowles, profile and contact.

Conclusion

Deciding whether to pay a contractor for poor work in Canada is rarely about the defect alone, it is about process, proportionality and evidence. You can often withhold, backcharge or refer a dispute to adjudication when work is defective, but the lawful route depends on your contract, the applicable provincial holdback and lien rules, and, in Ontario, the prompt payment and adjudication provisions of the Construction Act. Document defects from the first day, serve valid notices within the required timeframes, keep every deduction proportionate and auditable, and preserve your lien and adjudication deadlines. Where the amount is material or a dispute is escalating, get specialised construction counsel involved early, the quality of your first steps usually determines the outcome.

Sources

1. Ontario e-Laws, Construction Act
2. CanLII (Canadian Legal Information Institute)
3. Canadian College of Construction Lawyers (CCCL)
4. Law Society of Ontario
5. Canadian Bar Association