Application of the Black–Scholes Financial Model to Support Adaptability as a Sustainability Strategy for Buildings: A Case Study of an Adaptable Campus Parking Garage

In many construction projects, a “green premium” must be paid to implement sustainable designs that reduce environmental costs. Design for Adaptability (DfA) is a sustainable design philosophy that facilitates incremental renewal and infrastructure adaptation, thereby delaying future demolition and reconstruction. This paper focuses on the potential economic benefits of DfA. Notably, the paper contributes to answering the following question: is the green premium paid for an adaptable design justified by the potential long-term economic benefits? A modified version of the Black–Scholes financial options model is developed and demonstrated to address this question. A hypothetical case study of a parking garage is explored. This case study compares traditional and adaptable three-level parking garages and their potential expansion to a five-level garage at a future time. The “real option value” (i.e., the economic benefit of having the option to expand in the future) is calculated and compared under various assumptions and input parameters. The selection of reasonable model parameters for a given situation and the limitations of the Black–Scholes approach for valuing adaptable buildings are discussed. The model was developed for institutional (i.e., government or university) owners who consider their buildings as a cost of doing business without a direct relationship to revenue. It is concluded from the case study that the option value from the adaptable features of the parking garage exceeds the green premium given certain conditions. The payoff is most sensitive to the green premium, construction costs, and the owner’s inflation value on future additional parking. The work contributes to an economic case for DfA as a sustainability strategy for buildings.