The invoice is higher than the estimate. The explanation is "roofs always have extras." That may describe an awkward week, but it is not an itemized account of what you agreed to buy. Start with the estimate included in the contract and any changes you approved.
Ontario's home-renovation guidance says the final price cannot exceed an estimate included in the contract by more than 10% unless the customer has agreed to new work or a new price. The important words are about the agreement and its changes, not a universal allowance added to every roof invoice.
Dave puts the original scope on the left and the changes on the right. "Let's find the extra roof before we argue about the extra money." The exercise is reconciliation, not a verdict on anyone's character.
First, find the actual agreed price basis
Put the signed contract, attached estimate and scope beside the invoice. Was the price fixed for defined work? Were specific items priced by quantity? Does the estimate appear in the agreement, or only in an earlier email? Those details matter to interpreting the file.
A fixed price is not automatically entitled to a 10% uplift because a maximum-overrun rule exists. Likewise, a rough number discussed before the roof was inspected is not automatically the same document as the estimate incorporated into the signed work. If the paperwork conflicts, seek advice on the actual agreement instead of deciding from the word quote alone.
Our quote-reading guide helps separate the defined work from allowances. A unit price without an explanation of what is included can create its own argument when the quantity changes.
Put some arithmetic beside the words
For an uncomplicated hypothetical example, take an incorporated estimate of $12,000 on a consistent tax basis. Ten percent is $1,200, so 110% is $13,200. That is arithmetic for understanding the threshold, not an automatic entitlement to charge $13,200 or a ruling on a particular invoice.
Now imagine the owner later approves a separately described change. The question becomes what the change added, how it altered the agreement and what price was accepted. You cannot assess the final invoice merely by comparing it with the first number while ignoring an actual approved amendment.
Keep tax treatment consistent. Comparing a pre-tax estimate with a tax-included invoice manufactures a disagreement before anyone reaches the roofing work. Dave checks where the tax went. It has an impressive ability to reappear on the last page.
Reconcile the invoice in order
Compare documents on the same scope and tax basis before drawing a conclusion.
Original agreement
Locate the incorporated estimate and defined work.
Approved changes
Identify what changed and the recorded price agreement.
Final calculation
Reconcile quantities, credits and tax treatment.
Unresolved difference
Request the missing evidence and get advice on disputed obligations.
Hidden wood is evidence, not a blank cheque
Damaged decking can be a real discovery after tear-off. Ask for its location, the finding, proposed repair and price basis. The written change-order guide covers that specific process.
Ontario's guide for roofing businesses directs contractors to document and communicate scope changes in writing and have both parties sign the changed contract. A photograph of dark wood supports a conversation about condition; it does not by itself record your agreement to an undefined extra.
If urgent protection is needed while a decision is made, distinguish that temporary scope from the wider repair. Keep the house protected without allowing every discussion to collapse into "we had to do something."
Ask for a reconciliation, not another total
A useful written request identifies the original estimate, each claimed change, the approval record and the final calculation. For example: "Please reconcile the invoice to the attached agreement, identify the work behind each extra and provide the corresponding approval and price calculation."
Keep the request factual. A disputed amount may come from a missing credit, a quantity calculation, duplicated tax or a genuine disagreement over authorization. They need different answers. A louder email does not make the arithmetic easier to follow. On Dave's page, the unexplained amount gets a question mark, not a theory about the contractor's motives.
Do not assume the safe response is withholding every payment or signing a new document under pressure. Contract, lien and payment obligations can require prompt Ontario legal advice. Consumer Protection Ontario can explain the consumer complaint route, while a legal adviser can assess your particular agreement.
If the invoice still does not reconcile, the dispute-record guide helps organize the file. The useful outcome is a clear account of the work and price you authorized, not an argument over whether roofing is generally unpredictable.
