Fixed-Price vs. Cost-Plus vs. Time-and-Materials: Which Contract Should You Sign?

Ask three contractors for pricing on the same renovation and you might not just get three different numbers — you might get back three completely different kinds of documents. One is a single, all-in total. Another bills hourly plus materials as the work happens. A third asks you to pay actual costs plus a fee and trust the process.

All three are legitimate. All three are common in BC renovation work. But they don't distribute risk the same way, and the one you sign quietly decides who pays if the project costs more than expected — which, in an older Lower Mainland home, is a real possibility more often than not.

Here's what fixed-price, cost-plus, and time-and-materials contracts actually mean, when each one makes sense, and the one BC-specific rule that applies no matter which you choose.

Three Contract Types, One Underlying Question

Strip away the paperwork and every renovation contract is answering the same thing: who absorbs the cost if the project runs over budget? The pricing model is the answer. Everything else — how invoices are formatted, how change orders get handled, how much oversight you'll do yourself — flows from that one decision.

Fixed-Price (Lump Sum) Contracts

A fixed-price contract sets one total number for a clearly defined scope of work, agreed before a single wall comes down. The contractor has already priced labor, materials, permits, and a reasonable contingency into that number.

If costs run higher than the contractor estimated, that's the contractor's problem to absorb — not yours. If they come in under, they keep the difference. That's the trade: the contractor takes on the pricing risk in exchange for you accepting their number as final.

The catch is that a fixed-price quote is only as good as the scope behind it. A number built on a rushed walkthrough and vague allowances isn't really fixed — it's a lowball dressed up as one, and it tends to unravel through change orders once the walls are open. We've written a full breakdown of that pattern in fixed-price vs. lowball quotes, because the difference between the two is where most budget disasters start.

Cost-Plus Contracts

A cost-plus contract works differently: you pay the contractor's actual, documented cost of labor and materials, plus a fee on top — either a flat management fee or a percentage markup, commonly in the 15–20% range for residential work.

The appeal is flexibility. You can see itemized invoices, approve upgrades as you go, and start work before every design decision is locked down. That matters on genuinely undefined projects — a heritage restoration with unknown structural conditions, for instance, or a scope that's still evolving with an architect mid-project.

The tradeoff is that you carry the risk of overruns, not the contractor. Without a firm number, "cost plus" can drift well past what a homeowner expected — and the contractor has less built-in incentive to hunt for savings, since their fee often scales with total spend. Some cost-plus agreements include a guaranteed maximum price (GMP) or "not-to-exceed" cap to blunt this risk. If you're offered cost-plus pricing, that cap is worth asking for by name.

Time-and-Materials (T&M) Contracts

Time-and-materials billing charges an hourly labor rate plus the cost of materials used, sometimes with a small markup. It's the norm for small repairs, warranty callbacks, and service work where the scope genuinely can't be known ahead of time — a plumber tracing down a leak, for example, or emergency water-damage mitigation.

T&M is a reasonable, honest way to price a two-hour repair. It's a poor way to price a kitchen or whole-home renovation, because there's no ceiling on the total and no incentive built in to work efficiently. If a contractor proposes T&M pricing for a full-scope renovation with a defined outcome, ask why a fixed price isn't on the table.

At a Glance: How the Three Compare

	Fixed-Price	Cost-Plus	Time-and-Materials
Final price known before work starts	Yes	No (unless capped with a GMP)	No
Who carries cost-overrun risk	Contractor	Homeowner	Homeowner
Best suited to	Kitchens, bathrooms, whole-home renovations with a defined scope	Heritage restorations, evolving design-build scopes	Small repairs, warranty work, emergency service calls
Homeowner's ongoing effort	Low — approve the number once	Higher — review invoices, approve draws	Moderate — track hours and material receipts
Typical residential use	Common for most defined-scope renovations	Occasional, usually with a cap in place	Common for repairs, rare for full renovations

Key Insight: The question worth asking isn't "which contract type is cheapest?" It's "who is better positioned to absorb the risk of this project going over budget — me, or the person who's done this work hundreds of times?" For almost any renovation with a knowable scope, that answer points toward fixed-price.

Which Contract Type Actually Fits Your Project

• Scope is knowable ahead of time — a kitchen remodel, a bathroom renovation, a whole-home refresh with a clear finish package. This is the vast majority of residential projects, and it's exactly where a properly built fixed-price proposal belongs.
• Scope is genuinely undefined — you're restoring a century home with unknown structural conditions, or a design is still being finalized alongside an architect. Cost-plus with a hard maximum can make sense here, but push for that cap in writing.
• The job is small, urgent, or truly can't be scoped in advance — a repair, a service call, disaster mitigation. Time-and-materials is normal, appropriate, and nothing to be wary of at this scale.

Before signing anything, it's worth working through the broader vetting process too — our guide on questions to ask a contractor before you hire covers exactly what to ask about pricing, scope, and process regardless of which contract type is on the table.

The One Rule That Applies No Matter What You Sign

Here's something that surprises a lot of BC homeowners: regardless of whether your contract is fixed-price, cost-plus, or T&M, provincial law still requires a 10% statutory holdback on every payment you make.

Under BC's Builders Lien Act, the person paying for construction work — that's you, the homeowner — must hold back 10% of the value of each payment for 55 days after the work is completed, abandoned, or terminated. It exists to protect subtrades and suppliers who might otherwise go unpaid, and it isn't something a contractor can legally waive or ask you to skip, no matter how the rest of the contract is structured.

A contractor who understands this and builds it into their payment schedule without being asked is a good sign. One who pushes back on it, or asks you to release the full amount early, is worth a second look — that's covered in more depth in our guide to choosing a renovation contractor in BC.

Why We Build Every Project on a Fixed Price

We could offer cost-plus pricing. Plenty of respected contractors do, and for the right project — a scope that's genuinely still taking shape — it's a legitimate approach.

But most renovations aren't that. Most kitchens, bathrooms, and whole-home projects have a scope that can be defined properly before anyone picks up a hammer, if the contractor is willing to do that work up front instead of rushing to a number. As a full-scope general contractor and project manager, that's the harder job we take on before you sign anything: real allowances, a documented process for the unexpected, and one complete number.

That's the whole logic behind fixed-price. What we quote is what you pay — not because cost-plus is dishonest, but because for a defined renovation, there's no good reason to hand you the risk we're better positioned to carry.

Common Questions About Contract Types

Can a fixed-price contract still change after you sign it? Yes — but only through a documented change order that you approve, usually triggered by a scope change you request or a genuine surprise behind the walls (like undisclosed knob-and-tube wiring). What it shouldn't do is drift upward on its own with no paper trail.

Is cost-plus ever actually cheaper than fixed-price? Sometimes, on paper, if absolutely nothing goes wrong and the contractor works lean. In practice it's uncommon, because a fee that scales with total project cost gives the contractor less reason to control spending — and renovations rarely go exactly to plan.

Key Takeaways

• Fixed-price sets one total number upfront and puts the risk of overruns on the contractor — the right fit for most defined-scope kitchens, bathrooms, and whole-home renovations.
• Cost-plus bills actual costs plus a fee, offering flexibility for undefined scopes, but shifts overrun risk to you unless a guaranteed maximum price is negotiated.
• Time-and-materials suits small repairs and service calls, not full renovations, since there's no built-in ceiling on the total.
• BC's Builders Lien Act requires a 10% holdback on every payment regardless of contract type — it's law, not a negotiating point.
• Before signing anything, get the scope, allowances, and exclusions in writing, whichever pricing model you're offered.

FAQ

What's the main difference between fixed-price and cost-plus contracts? A fixed-price contract sets one total before work begins, with the contractor absorbing overrun risk. A cost-plus contract bills actual costs plus a fee as the project unfolds, with the homeowner carrying that risk unless a maximum price is capped in writing.

Is time-and-materials the same as cost-plus? They're related but not identical. T&M bills a set hourly labor rate plus material costs, typically for smaller or unpredictable jobs. Cost-plus usually applies to larger projects and bills verified actual costs plus a separate fee or markup.

Which contract type protects the homeowner most? For a renovation with a definable scope — which is most residential projects — fixed-price offers the most protection, because the total is locked in before you commit and the contractor carries the risk of underestimating.

Does the BC holdback rule apply even to a fixed-price contract? Yes. The 10% statutory holdback under the Builders Lien Act applies to every construction contract in the province, regardless of how the price itself is structured.

Can a contractor raise the price after a fixed-price contract is signed? Only through a proper, documented change order tied to a scope change or a genuine unforeseen condition — never as a silent adjustment. If a "fixed" price keeps moving without paperwork, that's not really a fixed-price contract.

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If you're comparing quotes and can't tell which pricing model you're actually being offered, that's worth sorting out before you sign anything. Reach out for a fixed-price estimate and we'll walk you through exactly what's included, what it costs, and why — in plain language, before you commit to a thing.