When you're planning a renovation or custom home, one early decision shapes everything that follows: do you hire a design-build firm that takes you from first sketch to final walkthrough under one contract, or do you engage your own designer/architect and then bring in a general contractor to build their drawings? Both work. They just distribute risk, cost certainty, and accountability differently. Here's how to choose.
The core difference
| Design-Build | Designer + General Contractor | |
|---|---|---|
| Contracts | One (design + construction) | Two or more (design, then build) |
| Accountability | Single team owns the whole result | Split between designer and builder |
| Cost certainty | Earlier — pricing checked during design | Later — after design is bid |
| Change orders | Fewer (buildability checked up front) | More common (design vs. site reality) |
| Best when | You want one accountable partner | You have a designer you love, or a finished design |
How design-build works
One team manages both the design and the construction. The builder is involved while the drawings are being developed, so the design is checked for buildability and budget as it's created — not after. The result is earlier cost certainty, fewer surprises, and no finger-pointing between "the architect" and "the contractor," because they're the same accountable team.
Design-build wins when you want a single point of accountability, cost certainty earlier in the process, and a smoother path from concept to completion. It's especially valuable on additions and custom homes where design decisions have big cost consequences.
How designer + general contractor works
You (or your architect) complete the design first, then the drawings go out to general contractors who price and build them. This is the traditional "design-bid-build" path.
This wins when you already have a completed design you love, or a strong relationship with a specific architect, and you want to competitively bid the construction. The trade-off: because pricing happens after design, a beautiful design can come back over budget — and reconciling the drawings with what's actually buildable (and affordable) often generates change orders once construction starts.
The cost question
Design-build is frequently more cost-predictable, not more expensive. Because pricing and buildability are pressure-tested during design, it tends to reduce the rework and change orders that inflate design-bid-build projects. In a separate model, the design and the budget can drift apart — and closing that gap costs money and time.
Under design-build, design and drawings typically run about 8–15% of the construction budget, folded into one contract you approve before the build begins.
How to decide
Ask yourself three questions:
- Do I already have a design (or a designer I'm committed to)? If yes, general contracting fits. If you're starting from scratch, design-build is usually smoother.
- How much does cost certainty matter to me, and how early? Design-build gives it to you sooner.
- Who do I want accountable when something goes wrong? Design-build gives you one throat to choke; the split model divides responsibility.
At Nexon Build we work both ways — full design-build, or as your general contractor on a design you already have. We'll recommend the structure that actually fits your project rather than the one that suits us.
FAQ
Is design-build more expensive than hiring separately? Usually not — it tends to reduce change orders and rework, which are what blow up design-bid-build budgets. It's more cost-predictable.
Can I use my own architect with design-build? Yes. We coordinate your architect or bring in design partners we've worked with, and manage the whole process either way.
When should I choose a general contractor instead? When you already have a completed design you love, or a designer you're committed to, and you want to bid the construction.
Who handles permits in each model? In design-build, we do. With a separate GC, it should be clearly assigned in the contract — always confirm who's responsible.
Deciding how to structure your project? See our design-build service and general contracting service, or read how to choose a contractor in Toronto.