A power floor treating assembly having an improved arrangement for housing and mounting the rotary brush or other floor maintenance tool for sealing the brush or tool enclosure from ambient. The apparatus includes a main frame along with a powered output shaft for driving the rotary brush. Housing means are coupled to the frame to define a brush or rotary tool receiving enclosure, along with a solid debris receiving chamber which is in communication with the brush receiving enclosure. The rotary tool receiving enclosure is an enclosed sector having generally closed ends with transverse walls including a top wall, side walls, and with an open bottom. In addition, a solid-air separator is provided with a fluid evacuation port being formed in one of the brush enclosure walls. A baffle is provided within the rotary tool receiving enclosure, with the baffle means being disposed adjacent one of the transverse walls, and extending generally parallel to the axis of the rotary tool, with the location of the baffle being generally between the fluid evacuation port and the bottom opening in the rotary tool receiving enclosure.