Fairfax County’s ageing schools are going years without mandated renovations, the system has run out of places to park the 1,5oo school buses in its fleet, and the custodians responsible for keeping hallways clean are significantly overworked.

That’s according to a new report from the school system’s Department of Facilities and Transportation. The annual report, presented to school board members Tuesday by Jeffrey Plantenberg, assistant superintendent for facilities and transportation, covered the 2011-2012 school year and evaluated the department on a variety of measures.

Overall, the department received good marks and included several successes. The district’s school buses, for example, generally deliver students on time, and a program to install water fountains at the county’s high schools has reduced the use of plastic and kept 102,803 water bottles out of landfills and recycling plants.

Although the report covered the 2011- 2012 school year, and fell under the leadership of the recently retired chief of facilities and transportation, many of the issues noted span several years, including crowded buildings.

Among the concerns highlighted: the school system will have to spend $6.25 million over the next few years to make all of its playgrounds compliant with federal handicap accessibility requirements.

The school system also must address the workload of its custodians. According to the report, the industry staffing benchmark is one custodian per 19,000 square feet. In Fairfax, the ratio is closer to one custodian per 22,500 square feet.

Additionally, the school system’s bus fleet is not only getting older — by the 2018-2019 school year more than 60 percent of the buses will be past the required replacement age — but the district has a hard time finding space to park them all.

The school system only has 500 permanent parking spots. The remaining buses, the report says, are stored “at the pleasure of schools and communities.”

That means school buses are kept at “ libraries, fire stations, commuter lots, HOA pool lots, drivers’ homes, and along public streets where possible.”

Much of the report attributes the school system’s problems to a lack of funding for capital improvement projects.

Under current bond limits, for example, the school system is unable to renovate buildings within the required 25-year time frame and instead completes such improvements at around 34 years after initial construction, according to the report.

“The increase in student enrollment and lack of sufficient funding are the major reasons that we are unable to achieve the desired time frame,” the report states.

The lack of funding also will lead to additional capacity issues. By 2014, the school system will be over its total capacity by 2,000 students. By 2018, that number will jump to 8,900 students.

The report attributes some of the capacity problems to the design of the buildings themselves.

For example, a new Fairfax County elementary school allots 104 square-feet per student. The average for the Washington region is 160 square feet per student, while the national average is 187 square feet. For the county’s high schools, about 150 square feet per student is allotted while the regional average is 221 square feet and the national average is 202.

The good news, however, is that the majority of Fairfax County schools are cost-efficient to build. New elementary and high schools in the county beat national and regional averages for construction costs, according to the report.