Abstract: A flooring system which enables floors of enhanced sound insulation to be produced with minimal raising of floor level above that for a simple floor comprises inverted channel section floor supports mounted longitudinally on joists and having outwardly directed flanges. Sound isolating material is interposed between the floor supports and the joists, panel members are laid between the floor support flanges, and floor decking extends over the panel members and is secured to the floor supports. Where the floor supports, which may be of a standard width, are substantially wider than the joists, locating clips may be interposed between the supports of the joists. The system is advantageously used in conjunction with a resiliently supported ceiling.