Abstract: A cleaning brush apparatus that is mountable onto a platform that is suitably suspended from a building for cleaning exterior and/or interior surfaces of the building. The cleaning brush apparatus includes a cleaning brush that is rotatable relative to the platform about a rotation axis that is parallel to the longitudinal axis of the platform. The cleaning brush apparatus is mounted to the platform in a manner to define a walkway on the platform to the rear of the rotation axis that permits a human operator to walk on the platform behind the rotation axis and along at least a length of the cleaning brush apparatus. The cleaning brush apparatus may also be adjustably mounted on the platform to permit the cleaning brush apparatus to be adjusted in position on and relative to the platform in a direction parallel to the longitudinal axis.