Progress Billing Construction: Rules & Worked Guide

Progress billing construction is an invoicing method where trade contractors, general contractors, and project consultants bill clients incrementally based on the percentage of work completed to date rather than waiting until project completion. In Canada, each progress claim ties back to a detailed schedule of values, tracks cumulative completed work, withholds statutory holdback, and calculates applicable taxes like GST. This process ensures steady cash flow while protecting project owners against non-performance.

Understanding Progress Billing in Construction

Large projects take months or years to deliver. When a contractor supplies labour, equipment, and materials for an extensive fit-out or structural build, funding the entire scope out of pocket creates severe liquidity risk. Progress billing solves this issue by breaking a fixed-price contract or unit-price scope into interim billing intervals, typically submitted monthly.

Instead of invoicing arbitrarily, the contractor bases every claim on a Schedule of Values (SOV). The SOV allocates the total contract price across discrete items of work, such as site grading, rough-in plumbing, mechanical distribution, and final testing. As work advances, the contractor assesses the physical percentage complete for each line item. The resulting percentage determines the gross earned revenue for the billing period.

Canadian construction contracts—such as standard CCDC contracts or custom trade agreements—rely on this cumulative accounting structure. Every progress invoice records the total contract value, cumulative work completed to date, previous amounts billed, current gross amount claimed, statutory holdback deductions, and applicable sales taxes. Managing this lifecycle cleanly avoids cash deficits and keeps all project stakeholders aligned on site completion.

The Governing Rules: Prompt Payment, Liens, and Taxes

In Canadian jurisdictions, progress billing is governed by strict statutory rules that protect trades and ensure money moves down the contracting chain without unnecessary delay. Alberta provides one of the clearest frameworks through the Prompt Payment and Construction Lien Act (PPCLA).

1. Statutory Holdback Requirements

Under Section 18 of Alberta's PPCLA, the owner or payer must retain a statutory holdback of 10% from every payment made to the contractor. This 10% holdback applies to the value of work actually done and materials actually furnished. It forms a statutory trust fund designed to protect subcontractors and suppliers lower down the chain in the event that an upstream contractor defaults. British Columbia, Ontario, Saskatchewan, and Manitoba mandate a similar 10% holdback under their respective lien statutes, whereas New Brunswick mandates 15% or 10% depending on the contract tier.

Statutory holdback is not retained indefinitely. Under the PPCLA, holdback must be released once the statutory lien filing period expires—normally 60 days after the date a certificate of substantial performance is issued, or contract completion if no certificate is issued. For specific scopes such as concrete work, the PPCLA extends the lien period to 90 days.

2. Prompt Payment Timelines

Alberta's PPCLA mandates strict payment timelines that begin the moment a contractor submits a "proper invoice" to the owner:

• 28 calendar days: The owner must pay the contractor within 28 days of receiving a proper invoice.
• 14 calendar days: If the owner disputes any portion of the invoice, they must issue a formal Notice of Dispute within 14 days, detailing the specific reasons for withholding payment and paying the undisputed portion.
• 7 calendar days: Once the general contractor receives payment, they have 7 calendar days to pay their subcontractors. Subcontractors then have 7 calendar days to pay their sub-subcontractors.

For an invoice to qualify as a proper invoice under Section 32.1 of the PPCLA, it must be in writing and include the contractor's name and address, invoice date, period covered, a description of the work completed, the amount requested, a breakdown of holdback, and a statement that the document is intended to be a proper invoice.

3. Canadian Sales Taxes and CRA Rules

Sales tax application on progress billings requires precision. In Alberta, only the 5% federal Goods and Services Tax (GST) applies. In Ontario, the 13% Harmonized Sales Tax (HST) applies, while provinces like British Columbia charge 5% GST alongside provincial sales tax rules on specific taxable contracts.

Under Section 168(2) of the Excise Tax Act, GST or HST on statutory holdbacks is not legally payable until the day the holdback is actually paid out, or the day the holdback period expires, whichever comes first. However, many contractors invoice the full tax up front on the net progress claim or report the entire gross tax liability immediately. For detailed tax mechanics on retainage, read our technical breakdown on Holdback Invoicing for Canadian Design Practices. Furthermore, Canada Revenue Agency (CRA) mandates that businesses retain all supporting books, records, and signed schedule of values sheets for at least six years from the end of the tax year to which they relate.

Worked Progress Claim Example with Real Numbers

To see how the math operates on a live project, consider an electrical subcontractor working in Calgary, Alberta. The subcontractor holds a fixed-price contract of $100,000.00 excluding GST. The project runs over three months.

The Approved Schedule of Values

• Item 1: Rough-in and Conduit Supply = $40,000.00
• Item 2: Equipment and Panel Installation = $30,000.00
• Item 3: Cable Pulling, Devices, and Commissioning = $30,000.00
• Total Contract Value: $100,000.00

Month 1 Progress Claim

By the end of Month 1, the site inspection confirms Item 1 is 50% complete. Items 2 and 3 have not started.

• Gross work completed to date: 50% of $40,000.00 = $20,000.00
• Less 10% statutory holdback: $20,000.00 × 0.10 = $2,000.00
• Net work completed to date: $18,000.00
• Less previous claims: $0.00
• Current Net Amount Due: $18,000.00
• 5% GST on current net due: $18,000.00 × 0.05 = $900.00
• Total Payable by Owner for Month 1: $18,900.00
• Holdback retained in trust: $2,000.00

Month 2 Progress Claim

During Month 2, the trade finishes the rough-in (Item 1 is now 100% complete) and completes 40% of the equipment installation (Item 2). Item 3 remains at 0%.

• Item 1 completed to date: 100% of $40,000.00 = $40,000.00
• Item 2 completed to date: 40% of $30,000.00 = $12,000.00
• Cumulative gross work to date: $40,000.00 + $12,000.00 = $52,000.00
• Cumulative 10% statutory holdback: $52,000.00 × 0.10 = $5,200.00
• Cumulative net earned to date: $52,000.00 − $5,200.00 = $46,800.00
• Less previously billed net (Month 1): $18,000.00
• Current Net Amount Due: $46,800.00 − $18,000.00 = $28,800.00
• 5% GST on current net due: $28,800.00 × 0.05 = $1,440.00
• Total Payable by Owner for Month 2: $30,240.00
• Cumulative holdback retained to date: $5,200.00

Notice that the current net billable amount is always derived cumulatively. Never calculate current billing by multiplying monthly delta percentages against line items in isolation. Cumulative calculations self-correct rounding errors and prevent compounding billing mistakes across multi-month projects.

Where Progress Billing Goes Wrong in Practice

While the mechanics appear straightforward on paper, real job sites create friction. Several recurring errors lead to delayed payments, statutory disputes, and cash flow shortages.

Front-Loading the Schedule of Values

Contractors sometimes attempt to inflate the financial weight of initial line items, such as mobilisation or temporary power, to draw cash early in the project lifecycle. Consultants and project managers acting as payment certifiers review the SOV closely. If the certifier determines an item is artificially front-loaded, they will reject the baseline schedule, resetting the invoice review period and delaying project cash flow.

Billing Unapproved Change Orders

Work on site changes constantly due to field conditions or revised drawings. Billing for unapproved change orders on a progress claim is one of the most common causes of rejected invoices. Under standard contracts and provincial prompt payment legislation, a change directive or change order must be formally approved in writing before it can be added as a line item on a proper invoice. If unapproved amounts are claimed, the owner has grounds to issue a Notice of Dispute under PPCLA Section 32.2, withholding payment on that portion.

Miscalculating Cumulative Totals

Accounting errors occur when trades calculate invoices based on monthly incremental progress rather than cumulative progress. If an estimator claims 25% progress in Month 1 and 30% progress in Month 2, but fails to account for previously certified amounts, discrepancies develop between contractor accounting records and the owner's payment certification ledger. Using software like BoltBill Pro maintains strict cumulative tracking across all claims, ensuring numbers tie back to the original contract.

Failing to Track Holdback Release Timelines

Subcontractors frequently forget to submit a separate invoice for their accrued statutory holdback once the 60-day lien period expires. Owners do not release holdback funds automatically. To trigger the release, trades must verify that no liens are registered against the title, ensure the certificate of substantial performance has been posted according to statutory requirements, and issue a dedicated holdback claim accompanied by a statutory declaration.

Checklist for Submitting a Construction Progress Claim

Follow this standard operating sequence before sending your monthly progress claim to the payment certifier or general contractor:

1. Perform Site Measurement: Conduct a physical site walkthrough with the client's representative or consulting engineer to agree on actual installed percentages for each line item on your approved Schedule of Values.
2. Update Approved Change Orders: Confirm that all change orders included on the claim have executed documentation signed by the owner or prime consultant.
3. Calculate Cumulative Math: Multiply total contract line values by the agreed completion percentage. Deduct the mandatory 10% statutory holdback from the cumulative earned total.
4. Subtract Previously Certified Work: Deduct the cumulative net amount billed on prior invoices to establish the net billing amount for the current period.
5. Apply Taxes Correctly: Calculate GST (5% in Alberta) on the net current billing amount, or as mandated by your provincial tax jurisdiction.
6. Format as a Proper Invoice: Ensure the invoice includes your business registration number, CRA GST/HST number, physical address, detailed scope narrative, and the explicit statutory title stating it is a "Proper Invoice" under the provincial Prompt Payment Act.
7. Attach Supporting Records: Provide vendor material delivery receipts, off-site storage agreements, and a signed Statutory Declaration (such as CCDC 9A or CCDC 9B) verifying that all second-tier subtrades and suppliers have been paid to date.
8. Archive Complete Billing Files: Store copies of the proper invoice, delivery tickets, inspector sign-offs, and payment receipts in your permanent accounting records to fulfill the CRA six-year record retention requirement.