What are the risks of cost plus in Toronto?

Cost-plus contracts carry real risks for Toronto homeowners, and understanding them before signing is critical — especially in a market where labour and material costs can shift quickly.

In a cost-plus arrangement, you pay the contractor's actual costs (labour, materials, subcontractors) plus a fee — either a fixed amount or a percentage (typically 10–20% in the GTA). The appeal is transparency, but the exposure can be significant if the contract isn't structured carefully.

The biggest risk is an uncapped budget. Without a Guaranteed Maximum Price (GMP) clause, there's no ceiling on what you can spend. A project estimated at $150,000 can drift to $200,000+ if scope isn't tightly defined, material prices spike, or productivity is slower than expected. Toronto's construction market is particularly volatile — lumber, steel, and concrete prices have swung dramatically in recent years, and labour rates in the GTA are among the highest in Canada.

Markup on subcontractors is another common issue. If your contractor is billing you cost-plus on their subs, and those subs are also marking up their own costs, you can end up paying a markup on a markup. Always clarify in writing how subcontractor invoices are handled and whether you have the right to audit them.

Slow or inefficient work becomes your problem. Under a fixed-price contract, the contractor absorbs the cost of inefficiency. Under cost-plus, you pay for every hour on site. A crew that takes 6 days instead of 4 costs you two extra days of labour at GTA rates — often $800–$1,500/day for a small crew.

Receipts and transparency vary widely. A reputable contractor will provide itemized invoices with backup receipts. Less scrupulous operators may inflate material costs or charge for time not actually worked. Always insist on an open-book policy — the right to review all invoices, receipts, and time sheets before payment.

How to Protect Yourself on a Cost-Plus Contract in Toronto

Insist on a Guaranteed Maximum Price (GMP) clause — this caps your total exposure while still allowing the contractor to bill actuals up to that ceiling. Pair this with a detailed scope of work document so there's no ambiguity about what's included. If the contractor resists a GMP, that's a red flag.

Make sure the contract specifies the markup percentage clearly — on labour, materials, and subcontractors separately. Ontario courts have upheld cost-plus contracts, but disputes over undefined markup structures are common and expensive to resolve. A construction lawyer reviewing your contract before signing is money well spent, typically $300–$600 for a review.

Cost-plus can actually be the right choice for complex renovations, heritage homes (common in The Annex, Cabbagetown, Rosedale), or projects where scope genuinely can't be defined upfront. In those cases, it's fairer to both parties than a contractor padding a fixed price to cover unknowns. The key is strong contract language, a trustworthy contractor with verifiable references, and active owner involvement throughout the project.

For Toronto homeowners, checking that your contractor carries WSIB coverage and $2M+ liability insurance is essential regardless of contract type — but especially on cost-plus where the relationship is longer and more collaborative.

You can find vetted, reputable contractors through the Toronto Construction Network directory, where professionals are reviewed by local homeowners who've been through exactly this process.