Comprehensive and Detailed Explanation (CSI-aligned, paraphrased)

In CSI’s project delivery guidance, constructability reviews are described as a structured way to have construction-experienced professionals—often contractors, CMs, or experienced field personnel—review the design during planning or design phases to determine:

Whether the design can be built efficiently and safely

How site conditions, constraints, and logistics will affect means and methods

Potential cost, schedule, and sequencing issues arising from unique or complex aspects of the project

Constructability reviews are especially valuable when:

The site is constrained (tight urban sites, limited access, nearby sensitive structures)

There are unusual ground, environmental, or logistical conditions

The work involves complex staging, phasing, or access issues

Option C. The site presents unusual challenges and constraints is therefore the clearest trigger for a constructability review, because it directly ties to the need to evaluate how the physical and logistical realities of the site affect construction feasibility, cost, and sequence.

Why the other options are less appropriate:

A. The client is unfamiliar with this type of project.This calls for more owner education, clearer communication, and perhaps additional planning or programming support—not specifically a constructability review. The core need is understanding, not constructability.

B. The project team consists of multiple new members.That suggests a need for team alignment, clarification of roles, and communication protocols. While new team members may benefit from constructability input, the main justification for a formal constructability review is project/site complexity, not simply team turnover.

D. The contractor is unable to commit to original schedule.This is a procurement or scheduling problem, often addressed through rescheduling, negotiation, or possibly re-bid. Constructability reviews are proactive during design; schedule commitment issues often arise later and are handled with different tools (e.g., schedule analysis, changes, resequencing).

Key CSI-Related References (titles only):

CSI Project Delivery Practice Guide – sections on constructability reviews and preconstruction services.

CSI CDT Study Materials – discussions of preconstruction evaluation, constructability, and risk identification.