Deferred design must be clearly identified using explicit statements addressed to the constructor, indicating the design responsibilities of the supporting registered professional or other competent individual when engineering acumen is not required as a part of the design solution. This way, the costs and time associated with the elements of deferred design can be accounted for without requiring extensive review of the full document set during the bid period. Currently, design professionals indicate ‘design intent’ within various components of the document set, which has the effect of making identification of the deferred design components implicit.
It is the RPR’s responsibility to identify information for the constructor to quickly and easily address deferred design solutions—in other words, to make the information explicit. Contractors only deal with what they can see and interpret from the contract language. Poorly coordinated or overly detailed components requiring deferred design solutions from constructors, which do not contain full identification of their responsibilities to provide design solutions, are considered implicit.
Design professionals are often remiss in their understanding of their role in describing deferred design responsibility to the constructor. This lack of knowledge leads some RPRs to believe they are removing liability from their own design language through the act of deferred design. Contractors are pointing out when deferred design is not described completely, the resulting gaps in coordination between technical solutions controlled by the constructor and the aesthetic and performance attributes directed by the design professional force the constructor to take on engineering responsibility for a part, which conflicts with the requirements of professional conduct and applicable building codes.
Traditional roles for deferred design performed by the constructor
Describing the contractor’s design obligations is not a new or unique concept. Design professionals have deferred aspects of design responsibility to contractors as long as there have been architects, engineers, and contractors. Deferring design works best when final design of specific elements is resolved as a component of construction deliverables, rather than a detailed portion of the construction document set.
The constructor has traditionally been responsible for design solutions associated with constructability (means and methods). There are cost benefits to the project when deferred design components form a part of the constructor’s solution that fits within their responsibilities for means and methods through effective scheduling and elimination of potential rework. For example, the RPR may provide the engineering information associated with connections between steel members or accumulated building load paths required for design of foundation components (piles, piers, and similar structures), while the constructor provides shop drawings containing the final design solutions. These solutions are prepared by a supporting registered professional to meet building code requirements for design responsibility, but the supporting registered professional does not take responsibility for the engineering of those components (which remains with the RPR).
The increasing complexity of construction through the latter half of the 20th century means it is becoming more common for design components to be described as forming a part of the constructor’s design contribution. This includes design of building elements not strictly associated with engineered outcomes of construction methodology. These components are typically pre-engineered (i.e. not requiring site-specific engineering) or require specialist contributions RPRs do not have within their knowledge base or experience.
There is increasing responsibility for building envelope and fire-protective solutions, conveying systems, and other pre-engineered elements forming a part of the deferred or collaborative design assigned or delegated as part of the contractor’s project deliverables. These form the basis for discussion in this practice guide.
