The decision that shapes the entire project
The choice of delivery model determines more than the contract.
It influences:
– when the contractor becomes involved
– how cost certainty is achieved
– how program is established
– how risk is understood and managed
– how design decisions are made
Yet it is often treated as a procedural step rather than a strategic one.
The delivery model defines how the project will be developed — not just how it will be built.
The traditional (separated) model
In a traditional model, the consultant team develops the design independently before a contractor is engaged through a competitive tender.
This provides:
– a high level of design control
– a fixed scope at tender stage
– a clear separation between design and construction
However, cost and program certainty are only achieved once the design is complete and the market has priced the project.
If the tender returns above budget, the project must be redesigned or re-tendered.
In a separated model, certainty arrives at the end of the design process.
The integrated model
An integrated model brings the contractor into the project during the design phase, allowing cost, program and buildability to be developed in parallel with the design.
This can occur through:
– Early Contractor Involvement, where the client retains the consultant team
– Design & Construct, where the contractor leads and coordinates the consultants
The difference is commercial structure — not project outcome.
Whether engaged through ECI or Design & Construct, an integrated model allows the project to be shaped within real cost and program parameters.
Why integration changes the outcome
When design and delivery are aligned from the outset:
– the budget is tested as the design develops
– buildability informs key decisions
– the program is based on real constraints
– procurement is planned progressively
– risks are identified while the project still has flexibility
This allows the project to be developed within known parameters rather than adjusted after they are exceeded.
Integration moves certainty forward — to the point where it has the greatest influence.
Risk and responsibility
The most significant difference between the two approaches is how risk is understood.
In a separated model:
Risk is transferred to the contractor at tender stage, often after key decisions have already been made.
In an integrated model:
Risk is progressively identified and managed during the design phase.
This creates:
– fewer late changes
– clearer scope definition
– more predictable outcomes
Projects are most successful when risks are resolved early — not transferred late.
When a separated model is appropriate
A traditional approach can be well suited to:
– projects with a fully resolved and coordinated design
– projects where the brief is unlikely to change
– programs that allow full documentation before contractor engagement
When an integrated model is most effective
An integrated approach is particularly effective when:
– program certainty is critical
– early cost alignment is required
– the project has complex services content
– the brief is still evolving
– staging or live environment delivery is required
It is also well suited to workplace projects where lease, design and delivery must be carefully aligned.
For most workplace projects, the real choice is between a separated model and an integrated one.
A commercial decision — not a contractual one
The selection of ECI or Design & Construct is typically a matter of commercial structure, procurement preference and project governance.
The objective in both cases is the same:
To develop the project with full visibility of cost, program and risk before construction begins.
The difference is not in the outcome — it is in the commercial structure that best suits the client and the project.
The outcome
With an integrated approach:
Design decisions are made within real budget parameters
Program dates are aligned with achievable construction durations
Procurement is planned rather than reactive
Construction begins with a fully understood and coordinated scope
Most importantly, the project proceeds with clarity, certainty and a shared understanding across the entire team.
The earlier the alignment, the greater the ability to influence the outcome.
Starting the conversation
The most effective time to consider the appropriate delivery model is during feasibility or immediately following the development of the test fit.
At this stage, the project still has the flexibility to adopt the approach that best supports its commercial and program objectives.
Discuss your project
If you are planning a workplace or commercial project and would like to explore which delivery model best aligns with your objectives, an initial discussion can help establish the right strategy.
