What does the 10 per cent estimate limit mean for an Ontario deck?

Under the Consumer Protection Act, 2002, if your agreement includes an estimate, the supplier shall not charge you more than 10 per cent above that estimate, and you may require the work at the estimated price.

The rule applies when the contract is a "direct agreement," meaning it was negotiated or concluded somewhere other than the supplier's place of business, such as at your home. The agreement must be in writing and delivered to you, and you have 10 days after receiving the written copy to cancel it without any reason.

A few things are worth understanding about how this works in practice.

• The rule is about an estimate the agreement includes, so get the estimate written into the contract itself.
• If you ask for something different, for example a larger deck, a different railing or added stairs, put that change in writing as a change to the agreement.
• We found no cap on deposits in the Act, so the deposit is whatever you and the builder agree to in writing.
• The Construction Act also applies: a deck is an "improvement," and the Act generally requires a 10 per cent holdback on each payment. Get advice for your specific situation before releasing any holdback.

The practical takeaway is that the estimate in your written contract carries real legal weight in Ontario. Before you sign, read it carefully and make sure every part of the scope you discussed is listed. If a builder says the price could change, ask them to explain under what circumstances and to put any allowances or exclusions in writing. Vague language like "materials subject to change" can create room for a bill that sits uncomfortably close to, or above, the 10 per cent ceiling.

If a final invoice comes in more than 10 per cent above the estimate, the Act says the supplier shall not charge that much. If there is a dispute, the Consumer Protection Act, 2002 is the starting point, but getting legal advice for your situation is worthwhile before taking any step.

The request form on this page sends your project details to Ottawa deck builders listed in the Ottawa Construction Network directory, so you can collect written estimates and compare them.