Provision, adequacy, utilization and management of educational facilities largely determine the quality and standards of education offered in a school yet there has been tremendous growth in students’ population without corresponding growth in number of facilities as a result of economic depression and corresponding rise in education cost. This has put much pressure on the existing facilities, thus it appears school facilities have been forced to depreciate faster than their normal rate of depreciation. The purpose of this study was to examine the contributions of principals on school building management. Specific objective of the study was to determine the contributions of principals on school machinery and equipment management. This study was anchored on Total Quality Management Theory. A review of literature on the contributions of the Principal on school plant management was done in line with the study objectives. The study adopted concurrent triangulation within a mixed method approach. The target population was 176 respondents; 35 principals, 35 deputy principals, 35 boarding/senior masters, 35 Parents Association Chairpersons, 35 Board of Management Chairpersons and 1 Sub County Quality Assurance and Standards Officer totaling to 176 respondents. Saturated sampling technique was used to sample 31 principals, 31 deputy principals, 31 Boarding/Senior Masters, 31 Parents Association Chairpersons, 31 Board of Management Chairpersons, and 1 Quality Assurance and Standards Officer totaling to 156. Data collection instruments were questionnaires and interview schedule. Face validity of the instruments was determined and ascertained by experts in the faculty of education, department of curriculum and education management while 4 schools from the sub-county were used for pilot study to determine reliability of the data collection instruments. Quantitative data were analyzed using descriptive statistics such as frequency counts, percentages and means. Qualitative data was transcribed, put into various categories and reported in an on-going process as themes and sub-themes emerged. The study found out that Principals contribute to school building management by ensuring proper supervision of the buildings and ensuring appropriate repairs are done; by ensuring approved physical plans are available in the schools where they work and by organizing budget which includes school maintenance. The study reported challenges in school plant management such as Poor Planning by some Principals, Principals’ Lack of technical skills in the school plant management, inadequate time for supervision by school principals, poorly trained personnel to manage school plant, Poor maintenance of school facilities by school principals, High cost of maintenance of the school plant, Careless and Destructive Students in schools and Insufficient Funds in schools. It was recommended that the Ministry of Education in Kenya should enact regular in-service courses for School Board of Management Chairpersons on the management of school plant. This would make school Board of Management to be updated on best ways of management of school plant and utilization of machinery.