Accounting Subcontractors for Construction

Introduction

A subcontractor can be slammed with work, invoicing every week, and still have no idea whether a job is actually profitable. That's the trap of treating construction accounting like ordinary small-business bookkeeping.

Construction work runs as dozens of mini-businesses, each with its own estimate, schedule, crew, and margin.

Labour, materials, equipment, other direct costs, subcontractor commitments, progress billings, retainage, change orders, and taxes all need to tie back to a specific project.

Get that wrong, and you can be busy and still run out of cash.

This guide breaks down what construction accounting actually involves for Canadian subcontractors. You'll get a practical workflow for staying on top of it, cash-flow controls that catch problems early, and clear signals for when outside accounting support makes sense.

Key Takeaways

• Every cost and invoice should connect to a specific project, phase, cost code, or contract
• Job costing, progress billing, holdback tracking, and change-order documentation drive reliable profitability numbers
• Cash-flow forecasting must account for payment timing, holdbacks, and delays elsewhere in the chain
• Worker classification, GST/HST treatment, and payroll obligations should be confirmed with a qualified Canadian professional

What Construction Accounting Means for Subcontractors

Standard small-business bookkeeping tracks revenue and expenses for one operation. Construction accounting tracks the same thing, multiplied across every active project, each with a different scope, billing schedule, crew assignment, and margin target.

Job Costing Beyond the Invoice

Job costing means assigning every dollar spent to the project that caused it. That includes:

• Direct labour (hours worked on-site, by project)
• Materials purchased for that specific job
• Equipment rental or usage allocated to the project
• Permits, project-specific insurance, and travel tied to the contract
• Subcontracted portions of the scope

Without this breakdown, you can't tell which jobs made money and which ones quietly drained it.

Direct Costs, Indirect Costs, and Overhead

Not every expense belongs in the job cost. A rough split looks like this:

Cost type	Example (electrical trade)	Where it lives
Direct cost	Wire, panels, labour hours on-site	Assigned to the project
Indirect cost	Site supervision across jobs	Allocated by formula
Overhead	Office rent, admin salaries	Company-wide, not job-specific
Pass-through	Permit fees billed to the owner	Tracked but not margin-bearing

The same logic applies whether you're doing plumbing, HVAC, roofing, concrete, or excavation — the categories don't change, only the line items do.

Canadian Tax and Payroll Essentials

Cost categories alone are not enough. These Canada-specific tax and payroll rules shape how construction work gets recorded, and they differ from US treatment:

• GST/HST timing: Construction-service payments are taxable on the earlier of payment received or the contractual due date, not when you choose to invoice. Refundable deposits differ from progress payments under CRA real property GST/HST guidance.
• Worker classification: The CRA reviews the full working relationship, not just whether someone invoices you, to decide employee vs. contractor status. Either party can request a formal ruling.
• T5018 reporting: If your business earns more than 50% of its income from construction, you generally need to report payments over C$500 (before GST/HST) to Canadian-resident subcontractors.
• Quebec businesses also need to track GST and QST registration thresholds separately, since the province applies its own rules.

If you run multiple entities, or separate crews under different numbers, keep distinct records for each. Mixing them makes job costing harder and creates extra work for your accountant.

Essential Accounting Practices and Controls for Construction Subcontractors

Good construction accounting follows a repeatable cycle, not a once-a-year scramble.

The Project File and Accounting Cycle

A complete project file should contain:

1. The subcontract agreement and scope of work
2. Schedule of values
3. Approved change orders
4. Purchase orders and delivery records
5. Timesheets and receipts
6. Invoices and payment correspondence

Run the same cycle on every job:

1. Collect contracts and purchase documents
2. Set up project and cost-code records
3. Capture labour and expenses as they happen
4. Issue compliant invoices
5. Reconcile bank and credit-card accounts
6. Review results weekly or monthly, not whenever there's time

Billing Methods That Fit the Contract

Different contracts call for different billing approaches:

• Progress billing — payments tied to set dates, percent complete, or milestones
• Lump-sum/stipulated price — a fixed contract amount, often using standard forms like CCA 1-2021
• Unit-price billing — payment based on actual measured quantities
• Time-and-materials billing — personnel and equipment rates tracked against site time

The right method depends on how well-defined the scope is before work starts. Fixed scope with a clear spec favours lump-sum; uncertain quantities favour unit pricing.

Retainage, Change Orders, and Monthly Reviews

Retainage (holdback) isn't a normal receivable. In BC, for example, the Builders Lien Act requires a 10% basic holdback with a 55-day release period tied to a completion certificate or project-completion trigger.

That holdback is a payment restriction, not a revenue-recognition rule, under the BC Builders Lien Act. Track release conditions and expected collection dates separately from your regular accounts receivable (AR).

Change orders need the same discipline:

• Document the requested change in writing
• Get approval before proceeding, where the contract requires it
• Update the budget and schedule
• Assign a new cost code
• Bill according to the contract terms

Finally, build in a recurring review comparing estimated cost, actual cost, committed cost, billings, and forecast margin. Catching a cost overrun in month two is a lot cheaper than catching it at job close.

Managing Cash Flow, Billing, and Payment Risk

A job can look profitable on your P&L and still leave you short on cash. That happens when you pay crews and suppliers before the progress payment lands, when holdback sits unpaid for months, or when an approval gets stuck.

Building a Project Cash-Flow Forecast

A basic forecast tracks:

• Expected labour and supplier payment dates
• Invoice dates and payment terms
• Holdback release timing
• Pending change-order approvals
• Any other known obligations

This isn't a one-time exercise. Update it as invoices go out and payments come in, so you can see shortfalls coming weeks ahead instead of the morning payroll is due.

Invoice Quality and the Payment Chain

Late payment is common enough that it shouldn't surprise anyone. A 2025 survey of 1,342 respondents across BC's industrial, commercial, institutional, and residential construction sectors found that 91% had been paid late at least once, and 93% had experienced delayed holdback payment, according to the BCCA 2025 Industry Survey.

That's an industry-wide signal, not a guaranteed outcome for every subcontractor. It is still a strong reason to tighten your own invoicing.

Reduce avoidable delays by making sure every invoice:

• Matches the subcontract and schedule of values
• Uses the required format or portal
• Includes supporting documents (timesheets, delivery slips, approved change orders)
• Clearly identifies the project and billing period
• Goes out promptly, not whenever there's a free afternoon

Payment-chain delays also come from:

• Missing documentation
• Disputed scope or unapproved changes
• Late payment further up the chain
• Incomplete closeout requirements

Prompt-payment and lien rules vary significantly by province. Ontario, Alberta, Saskatchewan, and BC each set different clocks for invoice response, payment timing, and lien deadlines. Review your contract remedies and talk to a construction lawyer before assuming a deadline applies the same way everywhere.

Following Up on Receivables

A documented AR process should include:

• Invoice confirmation on send
• Scheduled overdue reminders
• A clear escalation path for disputes
• Tracking of lien or prompt-payment deadlines where applicable

SolvedAF's work with Mercana on accounts payable and receivable shows the same discipline in practice: consistent invoice-approval workflows, quality checks that catch errors early, and weekly closing cycles. That cut capital tied up in payables and receivables, reduced vendor disputes and late-payment escalations, and gave purchasing clearer visibility.

Choosing Accounting Software and Deciding When to Outsource

What to Look for in Construction Accounting Software

Not every accounting platform handles job-level complexity well. Run your shortlist against this checklist:

Job and project controls:

• Project and cost-code tracking
• Estimate-versus-actual reporting
• Progress invoicing
• Retainage/holdback fields
• Change-order reporting

Operations and compliance:

• Payroll or time-tracking integration
• Document storage for contracts and approvals
• Bank feeds and audit trails
• User permissions by role
• Canadian tax support (GST/HST, T5018)

A solo trade contractor might manage fine with basic cloud bookkeeping. A subcontractor running multiple crews, or juggling several concurrent projects, usually outgrows that setup fast. The job-level visibility just isn't there anymore.

When to Bring in Outsourced or Fractional Support

Common signals it's time for outside help:

• Historical books are messy or out of date
• Month-end reporting is consistently late
• You're hiring faster than your finance process can keep up
• Multiple projects are running at once with weak job costing
• Cash-flow surprises keep happening
• There's no internal finance expertise to lean on

This is where SolvedAF fits in. We work with small and medium-sized businesses across Canada, including construction, on outsourced bookkeeping and fractional controller or CFO support.

Bookkeeping coverage includes AP, AR, payroll administration, reconciliations, and month-end close. Fractional support adds financial operations oversight, internal controls, and system optimization.

Our construction and real estate work focuses on vendor payments and project cost tracking, built around your existing tools. We support QuickBooks Online, Xero, FreshBooks, Dynamics, SAP, and other platforms.

Onboarding, including discovery, process documentation, and catch-up bookkeeping, typically takes 1 to 3 months. Outsourced bookkeeping can run up to 60% cheaper than hiring in-house, with no long-term commitment required.

If your books aren't telling you which jobs are actually making money, let's talk about what that would look like for your business.

Frequently Asked Questions

Who is considered a subcontractor?

A subcontractor is a business or individual engaged by a general contractor, prime contractor, or another subcontractor to perform a defined portion of construction work. Legal and tax classification depends on the actual contract and working relationship.

Are subcontractors the same as 1099s?

No. "1099" is a US tax reporting term and doesn't apply to Canadian worker classification. Canadian businesses should verify contractor-versus-employee status using CRA guidelines, not US rules.

Are subcontractors an expense or COGS?

It depends on the work performed, your chart of accounts, and reporting purpose. Project-specific subcontractor costs are commonly tracked as direct job costs or cost of goods sold, but confirm the final presentation with your accountant.

What are the common accounting methods used by contractors?

Contractors typically use cash-basis or accrual-basis bookkeeping, alongside construction-specific revenue recognition like percentage-of-completion under ASPE 3400. The right method depends on contract type and should be confirmed with a professional.

What is the best accounting software for subcontractors?

It depends on project volume, job-costing needs, billing method, retainage tracking, payroll, and Canadian tax requirements. Compare current platforms against those criteria before deciding.

How do you hold subcontractors accountable?

Use written scopes, milestones, approved change orders, timesheets, delivery records, and clear invoice requirements. Accounting controls support contract and site management, but they don't replace it.