A project consists of both retail and office space.

When selecting a LEED Interior Design and Construction rating system, the LEED AP should use the rating system that is appropriate for the majority of the project’s gross floorarea. If more than 50% of the project’s area can be appropriately rated under a particular system, then that system should be applied to the entire project.

References:

LEED v4: Interior Design + Construction Guide1

LEED rating system selection guidance2.

When determining the most applicable LEED Interior Design and Construction rating system for a mixed-use project, such as one consisting of both retail and office space, the general guideline is to choose the rating system that is appropriate for the majority of the project's gross floor area. If a specific LEED rating system covers more than 50% of the project's gross floor area, it should be selected for the entire project. This approach ensures that the chosen rating system aligns closely with the predominant use of the project, facilitating a more relevant and effective sustainability strategy that addresses the primary functions and needs of the space.References:

LEED v4 for Interior Design and Construction Reference Guide, particularly the sections outlining how to choose the appropriate rating system for mixed-use projects