A change order is a written, signed amendment that adds, removes or alters work and adjusts the price and schedule before the extra work proceeds. Get it in writing every time. Canadian courts will enforce a contract clause that requires written change orders, and a contractor who does verbal extras and bills for them later can lose the lot. On homeowner jobs in Ontario there is a second trap: you cannot charge more than 10% above your estimate without the customer's written consent, no matter how the costs ran.
What a change order must record
Every change order should capture:
- A clear description of the changed work
- The price adjustment, plus or minus
- Any change to the completion date
- Signatures of the parties (or their authorised representatives) dated before the work starts
On CCDC jobs this lives in GC 6 of CCDC 2 and the equivalent clause of CCA 1-2021. The contract also allows a Change Directive: the consultant can direct a change even where the price is not yet agreed, with valuation to follow. The work proceeds, but the paperwork and notice still have to be done.
The notice traps
Two appellate decisions frame the risk, and they cut both ways.
On the contractor's side, missing a contractual notice deadline can be fatal even when the underlying claim is sound. In Elite Construction v. Canada (2021), the Ontario Superior Court dismissed a $4.1 million extras claim outright because the contractor blew the contractual notice period of 10 working days from when the delay first occurred. The work was real; the claim died on procedure.
On the owner's side, courts will find waiver or apparent authority when the facts support it. An owner can be ordered to pay for extras it never formally signed off where a consultant or site supervisor with delegated authority directed the work and the owner watched it proceed without objection. In one Alberta case an owner was ordered to pay close to $1.5 million for extras it had never signed, because its consultant's conduct amounted to approval. None of that is a reason to rely on a handshake: it is expensive, slow litigation you would rather avoid.
The Ontario 10% estimate cap
On a consumer renovation in Ontario, the Consumer Protection Act, 2002 caps any overrun at 10% above the estimate unless the homeowner agrees in writing to more. This is the single most common way a contractor loses money on extras with homeowners. Cost-plus jobs are especially exposed, because every "estimate" you give can anchor the cap. The fix is simple: get written approval for each increase as it arises, before the cost is incurred. Alberta runs the same 10% rule with a hard maximum extra of $100 without consent. Quebec has no fixed statutory percentage, but the Civil Code's good-faith and reasonable-estimate duties apply, so the discipline is the same.
The new Consumer Protection Act, 2023 (Bill 142) passed in December 2023 but is not yet in force, so the 10% cap under the 2002 Act remains the rule today.
What verbal change orders do to your lien
There is a cost to informal extras. Under Ontario's Construction Act, unsigned or informal change orders may be left out of the contract value when Substantial Performance is calculated, which can shrink or delay your lien claim (see Adjudication and Your Dispute Routes). Doing extras off the books does not just risk the fee; it can weaken your security for the money you are already owed.
Best-practice discipline
- Before: a signed change order before work proceeds whenever possible; an email confirmation at the absolute minimum.
- During: site instructions in writing; track the extra work under its own cost code.
- After: never bundle approved and disputed extras in one final invoice without flagging which is which.
Common mistakes
- Doing the extra first and pricing it later. That is when the dispute starts.
- Relying on a verbal "yes" from the homeowner. It does not satisfy the written-consent requirement for the Ontario 10% cap.
- Missing the contract's notice clock. Elite Construction shows a valid claim can die purely on a missed deadline.
- Assuming the consultant's instruction binds the owner. Sometimes it does, sometimes it does not; written confirmation removes the gamble.
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