Despite the fascination and challenge of controlling and supervising the design activities of consultants, I believe most contractors do not prefer the design-and-build approach to procurement. This is because of the large potential for discovering problems during their design development stage, a risk which they are largely required to carry.
The problem in this approach often arises from a contractor's inability to appreciate when the designs have reached a stage where they represent adequate resolution of all essential issues surrounding projects.
If the consultant's 'design' role is supplementary or incidental to constructing projects, then greater cost effectiveness should accrue if this role can be eliminated altogether and reliance instead placed on contractors' experience and judgment.
Contractors have the ultimate power to deliver projects to clients. Consultants have the ability to plan and design projects, including their long-term potentialities.
Clearly, whichever side engages consultants, they would tend to work to optimise their interest.
Arvind Kumar (F), 2 Penn Road, Beaconseld, Bucks, HP9 2PX