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Construction & trades · London, Ontario

Contractor accountant in London, Ontario

New subdivisions keep pushing out on London’s north, south and west edges, and towns from St. Thomas to Strathroy are growing with them. That keeps framers, concrete crews, electricians, plumbers and renovators busy, and it keeps them dealing with holdbacks, draws and WSIB. EverStone works with London builders and trades remotely, at fixed fees.

Quick answer: A London, Ontario contractor has to track the Construction Act’s 10% holdback as a receivable until it is released, and charge 13% HST on each progress billing. It also has to report payments to subcontractors on T5018 slips six months after the reporting period, and keep WSIB coverage and clearance certificates current. EverStone handles those with the T2 and the monthly books, at a fixed fee. Published fees start at $300 a month for bookkeeping and $100 for a personal return.

The 10% holdback and when revenue turns into cash

Under Ontario’s Construction Act, the owner or the contractor above you keeps back 10% of each payment until the lien period has passed. The work is done and the invoice is issued, so the revenue has been earned, but the money arrives months later. On a big job that holdback can be the whole year’s profit sitting in someone else’s account. The books need a separate holdback receivable, by job, so you can see what is owed and chase its release. HST on a holdback generally becomes payable when the holdback is paid or becomes due, rather than on the original invoice, which is another reason to track it separately. Construction holdbacks explains the accounting.

Progress billing and work in progress

Custom home builders and larger renovation contractors bill in draws: foundation, framing, lock-up, drywall, completion. Each draw is an invoice with HST on it, whether or not the client has paid yet. At year-end, a job that has been worked on but not billed is work in progress and belongs on the balance sheet, and a job billed ahead of the work is a liability. Getting those two right is what makes one year’s profit comparable with the next. Ontario’s prompt payment rules also set timelines for paying proper invoices, which matters when you are both waiting on money and paying subcontractors.

Subcontractors and T5018 slips

A business whose main activity is construction reports payments to subcontractors for construction services on T5018 slips, due six months after the end of the reporting period. You choose a calendar-year or fiscal-year reporting period and stick with it. The simplest way to meet the deadline is to collect each subcontractor’s name, address and business number before the first cheque, not in a rush at filing time. The same review is where worker classification comes up: a helper who works only for you, on your schedule, with your tools, may be an employee in the CRA’s eyes whatever the invoice says. See the T5018 form and the T5018 subcontractor tracker.

WSIB: compulsory, and the clearance you ask for

Coverage with the Workplace Safety and Insurance Board is compulsory for most construction businesses in Ontario, including many independent operators and executive officers who do construction work. General contractors ask each subcontractor for a clearance certificate before paying them, because an uncovered subcontractor’s premiums can become the general contractor’s problem. Keeping your own clearance current, and collecting certificates from everyone you pay, is part of the monthly routine rather than something fixed when a builder refuses to pay. WSIB premiums sit on a separate account from anything the CRA sees.

HST on new homes and renovations

Construction and renovation services carry 13% HST, and the tax you pay on lumber, fixtures and equipment rental comes back as input tax credits. Builders of new homes have more to consider. The sale of a new house is taxable, and new housing rebates change what the buyer pays and how the contract is priced. A builder who rents out a unit it built can trigger self-supply rules that require HST on the unit’s value. Those are questions to settle before the first sale, not after. Your filing period depends on revenue, and many growing contractors move from annual to quarterly filing as the business passes $1.5 million.

Trucks, equipment and the vehicle log

Pickups, trailers, mini-excavators, scaffolding and tools are written off through capital cost allowance from the year they are available for use. A truck used partly for personal driving needs a vehicle log to support the business share, and the CRA asks for it in almost every review of a trades business. Timing a purchase before or after year-end changes the deduction, and trading in an old unit can bring recapture. The conversation belongs before the dealer does the paperwork.

What EverStone handles for you

One CPA and one fixed fee. A typical trades corporation bundle — bookkeeping, payroll and the year-end T2 with statements — usually runs $450–$650 a month. See what it costs.

  • Holdback receivable tracked job by job
  • Progress billing, WIP and deferred revenue at year-end
  • T5018 slips and subcontractor records
  • WSIB reporting and clearance checks
  • HST returns, including new housing questions
  • Crew payroll, remittances and T4s
  • T2 corporate return and financial statements for bonding and lenders
About this article
EverStone CPA

Prepared and reviewed by a Chartered Professional Accountant at EverStone CPA, an Abbotsford CPA firm working with small businesses and incorporated contractors across the Fraser Valley and Canada. Updated September 2026. About the firm  ·  Book a free consult

What a contractor has to get right

What a contractor has to get right The items that decide a construction year — for a business operating in London, Ontario
ItemWhy it matters
10% holdbackEarned revenue that arrives months later, tracked by job
Progress billingHST is charged on every draw, paid or not
T5018 slipsDue six months after the reporting period ends
WSIBCompulsory for most construction, with clearances for every subcontractor
Sales tax where you operate13% HST, a single registration and a single return

Source: Construction and trades accounting. General information, not advice.

Other services for London businesses: personal tax.

Common questions

London accounting for construction contractors FAQ

Is holdback income taxed before I receive it?+
The timing of income on holdbacks has its own rules, and HST on a holdback generally becomes payable when it is paid or due. Tracking holdbacks separately by job is what lets both be reported correctly. Ask about your case →
Do I need to file T5018 slips?+
If construction is your main business and you pay subcontractors for construction services, yes. They are due six months after the end of the reporting period you chose.
Do I need WSIB as a one-person company?+
In construction, often yes. Many independent operators and executive officers doing construction work need coverage, and general contractors will ask for your clearance certificate before paying you.
Should I incorporate my trade?+
Usually once profit exceeds what you need to live on, so the rest can stay in the company at the lower corporate rate. The incorporation calculator gives a first answer.
When do I have to register for HST?+
Once taxable sales pass $30,000 in four consecutive calendar quarters. Many contractors register earlier so they can claim input tax credits on tools and materials.
Our work slows down in winter. How do we plan for it?+
Exterior trades in Southwestern Ontario earn most of their year between spring and late fall. Setting aside HST, payroll remittances and the corporate tax balance as the money comes in, rather than when the bills arrive in a quiet January, is the simplest fix. A monthly view of cash against those obligations makes it visible.
A builder has not released my holdback. What can I do?+
The legal remedies belong to a construction lawyer, and the lien timelines are strict. On the accounting side, an aged holdback listing by job shows exactly what is outstanding and since when, which is what your lawyer will ask for first.
Do you work with contractors outside London?+
Yes. Trades in St. Thomas, Strathroy, Woodstock and across Middlesex and Elgin are served the same way, remotely.
What does an accountant cost for a London construction business?+
Nothing about a London address changes the fee. Monthly bookkeeping starts from $300 a month and a personal return from $100; a corporate return is quoted after a free consultation. A single question can go to a 45-minute Advice Call, a flat fee of $200 + GST. Every fee is fixed in writing first. See the published fees.
Do you work with businesses outside London itself?+
Yes. Contractors in St. Thomas, Strathroy, Woodstock and the rest of Middlesex County are served the same way as those in London, remotely and at the same fixed fees.

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Contracting in London, Ontario?

Holdbacks, progress billing, T5018s and WSIB handled by one CPA, with the T2 and HST on the same file. Fixed fee, fully online.

Remote contractor accounting from Abbotsford

EverStone is a sole practitioner CPA firm at 32615 South Fraser Way in Abbotsford, serving London, Ontario builders and trades entirely online. There is no London office and no local staff. Meetings run by video or phone at the start or end of the day, invoices and subcontractor paperwork come through a secure upload link from a phone on site, and no one has to leave a job for an appointment.

Talk to a CPA about this

One Chartered Professional Accountant, start to finish. Fixed fees, quoted in writing before any work begins, and no obligation from a first conversation.