The Truth About Cost-Plus Contracts

There is a video going around that says cost-plus is always over budget. We understand why it lands. A badly run cost-plus job genuinely does feel out of control, and plenty of homeowners have lived that. But what they experienced was an absence of process, and the contract took the blame for it.

We have run cost-plus projects across Vancouver, Burnaby, and the North Shore for decades, and the ones that stay predictable share the same things: a budget built in stages, invoices the client can see, and a standing meeting where the forecast gets updated whether or not there is bad news. Take those away and any contract structure drifts.

What a cost-plus contract actually is

Under a cost-plus contract you pay the actual cost of construction, labour, materials, permits, and subtrade invoices, plus an agreed fee for the builder's management and profit. That fee is either a fixed amount or a percentage of cost, and which one you agree to matters more than most homeowners realize.

The mechanism that makes it work is open-book accounting. You see the subtrade quotes, the supplier invoices, and the labour records that the billing is built from. In a fixed price contract those numbers belong to the builder and you never see them. In cost-plus they are yours to inspect, which is the whole point of the structure.

Fixed fee or percentage fee, and why it matters

A percentage fee rises with cost. That is the structural criticism people make of cost-plus, and it is a fair one to raise: if the fee grows with the total, the incentive to keep the total down is weaker.

A fixed management fee, agreed against a defined scope and adjusted only when the scope genuinely changes, removes that objection. Our view is that the fee arrangement is the first thing a homeowner should ask about, not the last. If a builder will not explain plainly how their fee behaves when the cost moves, that is the answer to your question.

Budgets built in stages, not issued once

The reason cost-plus feels uncertain to homeowners is usually that they were given a single early number and then nothing until invoices started arriving. We build the budget in four passes, each one tied to how complete the design actually is.

The first pass is a conceptual budget from early conversations about scope, site, and goals. It is meant for deciding whether the project makes sense at all, and we say so out loud so nobody treats it as a commitment.

The second comes when architectural drawings are roughly 25 to 30 percent complete. Design direction and initial finish level are visible, so the estimate narrows and the first real trade-offs surface while they are still cheap to make.

The third comes at roughly 60 to 75 percent drawings. Specific materials, mechanical and electrical systems, and construction methods are known, and the budget starts to resemble the final number rather than a range.

The fourth is prepared once drawings and specifications are complete, priced by the trades who will do the work, against current Metro Vancouver material and labour conditions. That is the number a homeowner should be making decisions against, and it exists before construction starts.

What this staging buys you is time. A cost driver identified at 30 percent drawings is a conversation. The same driver identified at framing is a change order.

Where cost-plus genuinely fits better than fixed price

Renovations of older Vancouver housing stock are the clearest case. A century-old house in Kitsilano, Mount Pleasant, or Grandview-Woodland hides its condition behind lath, plaster, and cladding. Undersized joists, knob-and-tube wiring, previous unpermitted work, and rot at the rim joist only become visible once demolition starts.

Asbestos is its own category. Anything built before 1990 may contain asbestos in flooring, drywall compound, insulation, and texture coat, and WorkSafeBC's asbestos requirements impose survey and abatement procedures before demolition. Nobody can price that accurately from the outside, and a builder who says they can is either loading the number or planning to argue about it later.

Cost-plus is also the better structure when the design is still moving. Some clients want to keep refining as the shape of the house becomes real on site, and forcing that project into a fixed price simply relocates the negotiation into a stack of change orders.

What we report, and how often

Transparency without a schedule is a promise rather than a system. What a homeowner should expect on a properly run cost-plus job is specific.

• Monthly cost-to-date against the current stage budget, by trade
• Copies of subtrade quotes and supplier invoices behind each billing
• A cost-to-complete forecast that gets revised, not just a running total of money spent
• Change orders written, priced, and approved before the work happens, never after
• A standing meeting to review the budget and forecast, held whether or not there is a problem

The cost-to-complete forecast is the item that separates real reporting from a fancy invoice. A running total tells you what you have spent. A forecast tells you where you will land, which is the only number that lets you make a decision while there is still time to make one.

Converting to a fixed price partway through

Cost-plus does not have to stay cost-plus. Once the design is finalized, the selections are made, and the trades have priced complete drawings, we can convert the remainder of the work to a fixed price.

That structure suits a lot of Metro Vancouver projects: flexibility while decisions are genuinely open, and a firm number in place before the bulk of the construction spending happens. If cost certainty is what you are ultimately after, our post on fixed price contracts walks through what a firm number needs behind it to be worth anything.

The safeguards that sit outside the contract

Two BC requirements protect you regardless of which contract type you choose, and they are worth confirming before you sign either.

The builder must be licensed. Section 14(1) of the Homeowner Protection Act states that a person must not carry on the business of a residential builder unless licensed, and section 22(1) states that a person must not build a new home unless it is registered for home warranty insurance. Check both on the BC Housing public registry, which also shows the warranty provider, past warranty claims, and any disciplinary action.

The holdback applies too. Under section 4 of the Builders Lien Act, the person primarily liable on a contract must retain 10 percent of the value of the work as it is provided. Section 20 gives subtrades 45 days after the certificate of completion to file a claim of lien, and section 8 sets the holdback period at 55 days. On a cost-plus job where you are paying invoices as they arrive, confirm how the holdback is being administered rather than assuming it is happening.

The questions that separate a good cost-plus builder from a bad one

Ask how the fee is structured and what happens to it when cost rises. Ask what you will receive each month and on what date. Ask to see a sample cost report from a real project with the client details removed. Ask whether the cost-to-complete forecast is updated monthly or only when something goes wrong.

Ask what gets marked up. Subtrade invoices, materials purchased directly, general conditions, site supervision, and rental equipment can each be handled differently, and the contract should say plainly which are billed at cost and which carry the fee.

A builder who answers all of that without hesitation is running a system. A builder who deflects to reassurance about trust and reputation is asking you to take on their risk on faith, and that is exactly the arrangement the video was complaining about.

Frequently asked