What Is Design and Construct (D&C)?
Design and construct (D&C) is a project delivery method where a single contractor takes contractual responsibility for both designing and building the works, rather than the client engaging an architect separately and then a builder to construct that finished design. The main appeal for clients is a single point of accountability — one contractor responsible for the whole outcome — usually in exchange for less direct control over design decisions than a traditional delivery method offers.
Key takeaways
- In a D&C contract, one contractor is responsible for both design and construction under a single contract with the client.
- It contrasts with traditional delivery, where the client engages an architect separately from the builder, who then constructs a design they didn’t create.
- D&C often starts from a client’s design brief or concept design, which the contractor develops and completes as part of its scope.
- Consultants engaged by the client at an early stage are frequently novated to the contractor once the D&C contract is signed.
- D&C typically shifts more design risk onto the contractor and gives the client faster, more predictable overall project delivery in return.
What is design and construct?
Design and construct — almost always shortened to D&C — is a delivery method where the client contracts with a single party for both the design and the construction of a project, instead of engaging an architect and a builder under two separate contracts. That single contractor, often called the D&C contractor, carries responsibility for turning the client’s brief into a completed, functioning building.
D&C sits in contrast to traditional delivery, where an architect designs the project to full documentation on the client’s behalf, and a separate builder then constructs exactly what’s been documented, typically with limited responsibility for the adequacy of the design itself. Under D&C, the contractor is responsible for both halves, which fundamentally changes where design risk sits.
A D&C project can start from very different points depending on how the client wants to run it — sometimes from just a performance brief describing what the client wants achieved, sometimes from a concept design the client has already had prepared, and sometimes from a more developed design that the contractor is asked to complete and construct.
In plain terms
Under D&C, you tell one contractor what you want, and they’re responsible for designing it and building it. You’re not the one holding the design risk between two separate parties who can each point at the other.
How a design and construct project typically runs
A typical D&C project moves through a reasonably consistent sequence, even though the amount of design the client has already commissioned before the D&C contract is signed can vary considerably from one project to the next.
- The client prepares a brief — sometimes with an early concept design — describing what it wants delivered
- D&C contractors tender for the project, pricing both the design development and the construction
- The client selects a preferred D&C contractor and signs the head contract
- Any consultants the client engaged directly are novated to the contractor, if the contract requires it
- The contractor completes the design, obtains approvals, and constructs the works under a single overall program
Design and construct vs traditional delivery
The clearest way to understand D&C is against the traditional delivery method it’s most often compared with.
- Contracts — D&C uses one contract for design and construction; traditional delivery uses a separate consultant agreement and a separate building contract.
- Design risk — D&C shifts design adequacy risk to the contractor; under traditional delivery, the client (via its architect) generally carries that risk.
- Client control — traditional delivery gives the client more direct, ongoing control over design decisions; D&C typically hands more of that control to the contractor once the brief is set.
- Speed and cost certainty — D&C can often start construction earlier and gives the client a more predictable overall price sooner, since one party is accountable for the whole outcome.
| Feature | Design and Construct | Traditional Delivery |
|---|---|---|
| Contracts | One, with the D&C contractor | Separate consultant and builder contracts |
| Design responsibility | Contractor | Client (via architect) |
| Client design control | Lower, after the brief is set | Higher, throughout design |
| Single point of accountability | Yes | No — design and construction split |
The role of novation in D&C
It’s common for a client to engage design consultants directly and progress the design to an agreed stage before a D&C contractor is even appointed — sometimes just a concept, sometimes as far as development approval. Once the D&C contract is signed, those consultants are frequently novated across to the contractor, so they continue the design under the contractor’s instruction rather than the client’s.
This gives the client the best of both positions in theory: enough early design input to shape what gets built, followed by a single point of contractual responsibility — the contractor — for finishing the design and constructing it. The mechanics of that handover, and exactly what liability the contractor takes on for design work done before novation, is where a novation deed needs to be precise.
Who uses design and construct, and why
D&C is common across commercial, industrial, government and larger residential projects where the client values price and program certainty more highly than granular, ongoing control over design decisions. Government agencies frequently favour D&C for exactly this reason — it consolidates risk with a single contractor and reduces the client’s exposure to disputes at the design-construction interface.
D&C contractors, for their part, take on more risk than a builder working from someone else’s finished documentation, but in exchange they get to design efficiently buildable solutions from the outset, rather than pricing and constructing a design they had no input into — which can materially improve their margin and program certainty if they manage the design risk well.
Pricing and tendering a design and construct project
Pricing a D&C tender is more demanding than pricing a straightforward construction-only job, because the contractor is pricing design development and approvals alongside the actual building work, often against a brief rather than a fully resolved set of drawings.
- Early cost planning against a brief or concept design, before documentation is complete
- Allowances for design development risk — the design may still change as it’s finished off
- Coordination of the design team’s fees alongside the construction cost plan
- A structured Bill of Quantities built up as the design reaches enough detail to measure accurately
- Ongoing re-pricing as design decisions are finalised through the contract period
Common mistakes with design and construct
Most D&C disputes and cost blowouts trace back to a handful of recurring issues rather than the delivery method itself being flawed:
- A brief that’s too vague, leaving the contractor and client with different expectations of what was actually promised
- Underestimating design development risk when the contract is priced against an early concept rather than finished documentation
- Novation gaps — unclear liability for design work done before the consultants were novated to the contractor
- Client design changes after the D&C contract is signed, which can trigger variations the client didn’t expect to pay for
How My Trade Hub helps on design and construct projects
My Trade Hub’s estimation engine helps D&C contractors keep pricing current as the design develops, measuring the latest drawings straight into a structured, editable Bill of Quantities rather than requiring a full manual re-measure every time the documentation changes.
That matters on D&C projects specifically, where the design is often still evolving after the contract is signed — because the takeoff is automated, contractors can re-price design changes and finalise their cost plan 60-75% faster than manual estimation, keeping the contract sum accurate as the project moves from brief to finished documentation.
Frequently asked questions
What does design and construct mean?
Design and construct (D&C) is a delivery method where a single contractor takes contractual responsibility for both designing and building a project, rather than the client engaging an architect and builder under separate contracts.
What is the difference between design and construct and traditional delivery?
Under D&C, one contractor is responsible for both design and construction under a single contract. Under traditional delivery, the client engages an architect to design the project and a separate builder to construct it, with design risk generally sitting with the client.
Who carries the design risk in a D&C contract?
The D&C contractor generally carries the risk that the design is adequate and buildable, since it is contractually responsible for delivering a completed, functioning project rather than simply constructing someone else’s documentation.
What does D&C stand for?
"D&C" stands for design and construct, a construction delivery method where one contractor is responsible for both the design and the construction of a project.
Are design consultants novated on a D&C project?
Often, yes. If the client engaged consultants directly before appointing a D&C contractor, those consultants are frequently novated to the contractor once the D&C contract is signed, so they continue the design under the contractor’s instruction.
Is design and construct cheaper than traditional delivery?
Not necessarily cheaper, but it often gives more price and program certainty earlier, because a single contractor is accountable for the whole outcome. The trade-off is generally less ongoing client control over design decisions once the brief is set.
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