The calculation and the remittance schedule are already automated by any compliant payroll system. What is still manual — and what AI can actually help with — sits either side of it: getting hours in, and getting questions answered.
Key takeaways
"Automating payroll" in a construction business usually means one of two very different things. Sometimes it means getting off spreadsheets and onto a payroll system that calculates deductions and files remittances — which is not an AI question at all, and is worth doing regardless. Sometimes it means removing the week of chasing that happens before payroll can even start. The second is where the real cost sits, and where new tooling helps.
Subsection 153(1) of the Income Tax Act requires a person paying salary, wages or other remuneration to deduct or withhold the amount determined in accordance with prescribed rules and, at the prescribed time, remit it to the Receiver General on account of the payee's tax. Section 21 of the Canada Pension Plan imposes the parallel duty for Canada Pension Plan contributions, requiring the employer to deduct the employee's contribution from remuneration paid and remit it with the employer's own contribution.
When to remit is set by section 108 of the Income Tax Regulations. The default in subsection 108(1) is that amounts deducted or withheld in a month are remitted on or before the 15th day of the following month. Subsection 108(1.1) accelerates that for larger employers by reference to the average monthly withholding amount for the second preceding calendar year: at $25,000 or more but less than $100,000, amounts withheld from payments made before the 16th of a month are due by the 25th of that month and amounts from payments after the 15th by the 10th of the following month; at $100,000 or more the schedule tightens further. Subsection 108(2) requires an employer who has ceased to carry on business to remit outstanding amounts within seven days of ceasing.
Two consequences worth internalising. First, your remittance schedule can change between years as your payroll grows, and the change is driven by a figure from two years earlier — not something to discover from a penalty notice. Second, none of these duties is transferred by using a payroll provider. Our sister firm covers the sharpest edge of that in whether a director can be personally liable for unpaid payroll deductions, and what an audit examines in this note on a CRA payroll audit.
Federal deductions are only half of it. Employment standards entitlements are provincial, and they are calculated from the same hours your field system does or does not capture properly.
In Ontario, the Ministry's guides set out overtime pay, public holidays and vacation. Each depends on an accurate record of what was worked and when, and the record-keeping guide requires the dates and times worked and the hours in each day and each week to be recorded and retained for three years after the day or week of work.
Crews that cross provincial lines add a further layer, since the applicable employment standards regime and the deduction treatment do not always follow the head office — a question to settle with advice rather than assumption before the first pay run.
In Ontario the WSIB sets reporting frequency by insurable earnings. Its guidance on reporting payroll and paying premiums gives the thresholds — monthly reporting at insurable earnings of $1,000,000 or more, quarterly from $20,000 to $999,999.99, and annual below $20,000 — and notes that where actual insurable earnings become higher than the estimate, you should contact the WSIB within 10 calendar days, as failing to do so can result in penalties. How the premium itself is worked out is set out on the WSIB's page on calculating your premium and insurable earnings.
Construction also has coverage rules that catch owner-operators and small contractors who assume they are outside the system — see the WSIB on expanded compulsory coverage in the construction industry. Outside Ontario the equivalent board sets its own rules, and the deadlines do not align.
Getting hours in. This is the real bottleneck, and it is upstream of payroll entirely. Voice or mobile capture at the end of a shift, coded to a job, approved next morning by the foreman. Field time tools document this workflow directly — see Procore's project timesheets and Timecard tool, which covers weekly entry, billable hours by project, copying a previous week, and reporting filtered by date, employee, project and billable status.
Catching anomalies before the run, not after. A worker with hours on a job that closed, a shift longer than your policy allows, a pay period where someone has no hours at all, a rate that changed without a note. A flag is cheap; a corrected pay run is not.
Allocating labour across jobs. Payroll needs total hours; job costing needs them split. If the split happens at capture, both are served by one action. If it happens afterwards, someone reconstructs it, and that reconstruction is where job costs quietly go wrong.
Answering the questions. "Why is my cheque different this week" arrives at the office, not the software. A model that drafts a plain-language explanation from the actual pay data — for a person to check and send — removes a real recurring cost. Note the order: draft, check, send.
Two decisions in construction payroll are legal characterisations, and both should stay with people who can be accountable for them.
The first is employee or subcontractor. Our sister firm covers the immediate question in whether you must deduct when paying an independent contractor, and the exposure in CRA penalties for worker misclassification. A payroll system that lets a category be set by a dropdown without a record of who decided and why is storing up trouble.
The second is what counts as remuneration — allowances, use of a truck, meals on a long day, a bonus at Christmas. These are characterisation questions with deduction consequences, and the honest answer is that they are advice questions, not prompt questions.
A growing GC, twenty on the tools, illustrative
The symptom. Payroll takes a day and a half every two weeks, most of it chasing timesheets and resolving which job hours belonged to. Remittances are made on time, but only because the owner remembers.
Fix one. Daily mobile capture with job selection at the start of the shift and foreman approval the next morning. The chasing disappears because the record is made while people are still on site.
Fix two. Pre-run checks: hours on closed jobs, shifts over twelve hours, employees with zero hours, rate changes without a note. Roughly a handful of flags per run, resolved in minutes.
Fix three. The remittance schedule is put in the calendar against the section 108 rules rather than in the owner's head, and reviewed each January against the prior-prior year's average monthly withholding amount.
Fix four. A standing note of when WSIB reporting is due for the applicable earnings band, with a reminder to update the estimate within 10 days if actual insurable earnings run ahead of it.
Result. Payroll drops to a couple of hours, and job costing gets accurate labour as a by-product — which was worth more than the time saved.
Commercial arrangements vary and are worth reading closely, but the statutory duty to withhold and remit sits with the payer under subsection 153(1) of the Income Tax Act. Treat provider guarantees as a commercial remedy, not as a transfer of obligation, and see our sister firm on personal exposure for unremitted deductions.
The thresholds in subsection 108(1.1) of the Income Tax Regulations key off the average monthly withholding amount for the second preceding calendar year, so it is a predictable annual check rather than a surprise. Put it in the January calendar alongside your other year-start tasks.
Payroll data is personal information about identifiable people, so the Privacy Commissioner's summary of PIPEDA requirements is the right frame: identify the purpose, limit collection and use, and safeguard it. In practice, prefer tools that work inside your payroll system over pasting pay data into a general chat interface.
Ontario employment records: three years, per the Ministry's record-keeping guide. Tax records: six years from the end of the last taxation year concerned under paragraph 230(4)(b) of the Income Tax Act, and electronically readable for that period under subsection 230(4.1) if kept electronically.
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