0.1.III Design-Build (DB)

The Canadian Handbook of Practice (CHOP) in Chapter 2.3.2 gives a good overview of the DB method of project delivery, including advantages and disadvantages. As with Construction Management projects, or any project for that matter, clarity in roles and responsibilities is paramount to a successful project. However, with both the architect and contractor working under a single entity of ‘Design-Builder’ this may become an internal discussion about their agreement without an independent perspective and dependant on who leads (the contractor or the architect) the DB entity. 
The success of a Design Build project of course also depends on the project requirements including programmatic, technical and budget parameters, which would include performance specifications being well defined without ambiguity at the outset. These are usually prepared by an Owner with an Architect or another Consultant prior to the award of the project to a Design Build company.
It is based on the above considerations that the successful Design Build proponent (now a Contractor and another Architect) develops their design and final specifications for the construction of the project based on the specific requirements they are obliged to meet.   Ambiguities or conflicts in the parameters that may not be apparent from the outset may be exacerbated in the final execution of a project, for example where the performance specifications does not included adequate provisions to meet the intended programmatic needs yet is technically met in the final specifications of the project.
The writer recalls for example a situation that occurred on a trade school project for a mechanics teaching shop. The owner’s requirements included performance specifications for exhaust fans needed while the car engines would be running (while teaching students). The fans provided did meet the performance specifications, and came with an internal or external (roof top) mounting option. The internal option was implemented (perhaps saving the cost of some roof detailing, or in the equipment itself). This, however, resulted in a practically unusable condition in that the noise of the fans was far too loud for the professors to teach their students while working on the vehicles (one might argue, therefore not meeting the basic programmatic needs). Unfortunately, noise criteria were not included in the project requirements, perhaps based on a presumption that the exhaust fans would be roof top mounted and noise was not considered to be a significant concern. 
There are usually multiple solutions that meet the stated requirements, each with advantages and disadvantages as to cost, performance, and/or meeting programmatic needs, and it may be difficult to determine the best advice to give or the best solution to implement for a client or an owner. The architect is cautioned to uphold their professional obligations especially if under pressure from their client (the Design Builder) to reduce costs.