Estimating facilities maintenance cost using post-occupancy evaluation and fuzzy set theory

Purpose The purpose of this paper is to introduce a new general approach for estimating the maintenance cost of constructed facilities. The proposed approach consists of four components, including: facility work breakdown structure; historical maintenance cost and cost contingency data of actual completed projects; feedback obtained from the post-occupancy evaluation (POE); and fuzzy set theory (FST) to define the uncertainty associated with the maintenance cost and cost contingency as an alternative approach to simulation. Design/methodology/approach Literature review of the existing methods used for estimating maintenance cost of constructed facilities was conducted to highlight the limitations of the existing methods and models. The paper then introduced a new approach in which the results obtained from POE are integrated with the estimator's judgment in estimating maintenance cost of constructed facility. As a proof of concept, the developed approach is tested on a private school facility in the city of Khobar, Saudi Arabia. The application of the proposed approach in this case project demonstrates its applicability and features in comparison with the existing practice. Findings The application of the developed approach on a school case project demonstrated that the developed approach can provide a reliable facility maintenance cost estimate, narrow the uncertainties and vagueness associated with the estimated cost, and provide the estimator with the necessary information to conduct risk analysis with less effort, less computations and less complexity comparing with that provided by complex simulation. The results also showed that integrating POE in the estimating process can provide more accurate cost estimate with high level of confidence. Originality/value The paper presents a new approach for estimating facility maintenance cost. The developed approach introduced a new concept that assists maintenance contractors in preparing facility maintenance estimate with improved accuracy while satisfying the facility user's needs. The proposed approach integrates the estimator's judgment with POE to model the uncertainties associated with cost using FST as an alternative approach for complex simulation.