The Collaborative International Dictionary of English v.0.48:

maintenance staff \maintenance staff\ n.
   Those persons in a business responsible for maintaining the
   physical plant in good condition.

   Syn: service staff, maintenance crew.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

maintenance staff
    n 1: those in a business responsible for maintaining the
         physical plant [syn: service staff, maintenance staff]