When choosing a project procurement method, design and build (“D&B”) remains an appealing option for employers, providing a single point of responsibility for project delivery.  The original approach to D&B involved the employer specifying an operational output in its Employer’s Requirements and the contractor providing a fixed price, lump sum for designing and building the project to meet that output.

This approach may work well on routine buildings, or projects where the employer does not want, or require, any significant input into the design process. There are also likely to be programme advantages - the contractor can, for example, start on site before the design is fully complete or place orders for any long lead items.

However, if the employer requires greater control over the design of its project, or input into how the output specification is achieved, the above approach will not be suitable.  This has led to a different approach to design and build, with employers taking the design of the project as far as RIBA Stage 3 (Developed Design) or Stage 4 (Technical Design) and involving the contractor at that much later stage. The professional team is novated to the contractor to maintain the “single-point responsibility” advantage of D&B contracting.

As well as design control, there are other advantages to  this employer-led design approach. As the Employer’s Requirements can be more detailed and developed there is a reduced risk of the contractor “interpreting” the Employer’s Requirements in a way not intended. The employer can also be more certain that the Employer’s Requirements do in fact meet its requirements, reducing the risk of costly variations on the project.

However, this approach may be more expensive as the contractor will have to price for the risk of errors in another party’s design.  The programme is also likely to be impacted as there is less scope for the contractor to get on site early and it may well have to “start from scratch” in terms of assessing the design and buildability after the design has been developed by the employer. This approach may also be considered to be less collaborative.  That said, these issues can be mitigated through early involvement of the contractor (for example, through adopting a two stage procurement process).

The choice between the two above approaches (or whether you land somewhere in between) will ultimately come down to the particular project and requirements of the employer involved, but it should be remembered that D&B is not a “one size fits all” procurement method, and can be tailored to the particular needs of any employer or project.